Applied Surface Science (v.258, #2)

Evaluation of residual iron in carbon nanotubes purified by acid treatments by E.R. Edwards; E.F. Antunes; E.C. Botelho; M.R. Baldan; E.J. Corat (641-648).
► We produced multi-walled carbon nanotubes powder by pyrolysis of camphor mixed with ferrocene, and then used non-oxidative and oxidative acidic treatments for iron removal. ► We analyzed the elimination and/or oxidation of iron nanoparticles by X-ray photoelectron spectroscopy, monitoring Fe2p, O1s and C1s peaks. ► We carried out complementary investigation by thermogravimetric analysis, atomic absorption spectroscopy, Raman Spectroscopy and transmission electron microscopy (TEM) to evaluate the effectiveness of each treatment. ► A purity degree higher than 98% was achieved only with non-oxidative treatments using sonification process.A detailed analysis by X-ray photoelectron spectroscopy was carried out on multi-walled carbon nanotube (MWCNT) surfaces after non-oxidative and oxidative purification treatments in liquid-phase. The MWCNT were produced by pyrolysis of camphor and ferrocene, that provides a high yield but with high iron contamination (∼15% wt). The elimination and/or oxidation of iron nanoparticles were monitored by Fe2p and O1s core level. Oxygen-based functional groups attachment was also investigated by C1s fitting. The effectiveness of each treatment in iron removal was evaluated by thermogravimetric analysis (TGA) and atomic absorption spectroscopy (AAS). The integrity of the MWCNT structure was verified by Raman spectroscopy (RS) and transmission electron microscopy (TEM). A purity degree higher than 98% was achieved only with non-oxidative treatments using sonification process.
Keywords: Iron purification; XPS; MWCNT; Acid treatment; Camphor; Ferrocene;

Fabrication and characterization of indium sulfide thin films deposited on SAMs modified substrates surfaces by chemical bath deposition by Xu Meng; Yongjuan Lu; Xiaoliang Zhang; Baoping Yang; Gewen Yi; Junhong Jia (649-656).
► In2S3 thin films were successfully deposited on the APTS layers modified ITO glass substrates using the chemical bath deposition technique. ► The detailed time-dependent evolutions of surface morphology, crystal phase and composition of In2S3 thin films were characterized. ► The correlations between the optical properties, photocurrent response and the thickness of thin films were established. ► Positive and negative micropatterned In2S3 thin films were successfully fabricated on modified Si substrates by combining CBD with UV lithography process.In an effort to explore the optoelectronic properties of nanostructured indium sulfide (In2S3) thin films for a wide range of applications, the In2S3 thin films were successfully deposited on the APTS layers (–NH2-terminated) modified ITO glass substrates using the chemical bath deposition technique. The surface morphology, structure and composition of the resultant In2S3 thin films were characterized by FESEM, XRD, and XPS, respectively. Also, the correlations between the optical properties, photocurrent response and the thickness of thin films were established. According to the different deposition mechanisms on the varying SAMs terminational groups, the positive and negative micropatterned In2S3 thin films were successfully fabricated on modified Si substrates surface combining with the ultraviolet lithography process. This offers an attractive opportunity to fabricate patterned In2S3 thin films for controlling the spatial positioning of functional materials in microsystems.
Keywords: Indium sulfide; Thin films; Self-assembled monolayers; Photoelectrochemical property; Micropattern;

Dual roles of amphiphilic triblock copolymer P123 in synthesis of α-Fe nanoparticle/ordered mesoporous silica composites by Jiansheng Li; Huijun Li; Ye Zhu; Yanxia Hao; Xiuyun Sun; Lianjun Wang (657-661).
A simple method for synthesis of α-Fe nanoparticle/ordered mesoporous silica composites is reported. Amphiphilic triblock copolymer P123 plays dual roles in evaporation induced self-assembly and carbothermal reduction.Display Omitted► Well dispersed α-Fe nanoparticles in ordered mesoporous silica has been synthesized. ► Evaporation induced self-assembly is strategically combined with carbothermal reduction. ► Fe species can be in situ reduced to α-Fe nanoparticles via carbothermal reduction. ► Amphiphilic triblock copolymer P123 plays dual roles in self-assembly and carbothermal reduction.A simple and effective method for in situ synthesis of α-Fe nanoparticle/ordered mesoporous silica (OMS) composites is reported. Evaporation induced self-assembly (EISA) and carbothermal reduction (CR) are strategically combined by using amphiphilic triblock copolymer P123 as not only a template and but also a precursor of carbon material. P123 plays dual roles in assembly of mesostructure and reduction of ferric species. Thermogravimetric analysis–mass spectrometer was used to investigate the pyrolysis process of the wet gels. The synthesized composites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscope (XPS) and N2 adsorption. The results showed that the composites possess ordered hexagonal mesoporous structure and the α-Fe nanoparticles with about 16 nm were well dispersed in mesoporous matrix. The carbon material resulting from P123 can reduce ferric species to α-Fe nanoparticles at 800 °C. Moreover, the formation mechanism for Fe nanoparticles in OMS matrix is proposed.
Keywords: Synthesis; α-Fe nanoparticle; Mesoporous silica; Carbothermal reduction;

Superhydrophobic brocades modified with aligned ZnO nanorods by Gaocan Qi; Huan Zhang; Zhihao Yuan (662-667).
. The Brocade modified with aligned ZnO nanorods exhibits water-repellent function with a superhydrophobic surface.Display Omitted► Aligned ZnO nanorods modified on brocade are synthesized in tepid temperature. ► The modified brocade reveals excellent waterproof properties. ► The superhydrophobic surface is fabricated without any unsafe organic substance. ► The waterproof brocades can be used for some special and protective drygoods.A superhydrophobic ZnO oriented nanorods coating on brocade substrate was prepared by a low-temperature wet chemical route, and the corresponding waterproof properties were evaluated. From wetting measurement, the modified brocades have a water contact angle of ∼152° and roll-off angle of 9° to a 10 μL water-droplet. A direct immersion of the modified brocades in water gives a strongly water-repellent behavior. The obtained waterproof brocades offer an opportunity for fabricating some special and protective drygoods.
Keywords: Superhydrophobicity; Surface modification; ZnO nanorod; Textile;

Degradation factors of a new long life cathode by Mingchen Zhang; Honglai Zhang; Pukun Liu; Yutao Li (668-671).
► We development a new long life cathode and take an accelerated life test for them. ► We investigate the surface state of the cathode after life test with SEM and AES. ► The analyzing results show the degradation factors of the cathode.This paper analyses the degradation factors of a new long life coated impregnated cathode after accelerated life test. The surface state of the cathode is investigated with scanning electron microscope (SEM) as well as the content and variation of the various elements on the surface and the longitudinal section of the cathode are analyzed with Auger electron spectroscopy (AES) before and after the life test. The analyzing results with SEM show that the cathode coating shrinks at the life end and leads to a rise in its work function. The analyzing results with AES show that the percent of the W increases and the active materials Ba decreases on the cathode surface at the life end. Furthermore, there is less Ba underneath the cathode surface but still a lot of Ba in the tungsten matrix at the life end.
Keywords: The impregnated Ba–W cathodes; Long-life cathode; Accelerated life test;

Synthesis, characterizations, photocatalytic and sensing studies of ZnO nanocapsules by M. Faisal; Sher Bahadar Khan; Mohammed M. Rahman; Aslam Jamal; Abdullah M. Asiri; M.M. Abdullah (672-677).
► Newly synthesis of ZnO nanocapsule at low temperature by hydrothermal method. ► First report on chloroform sensing using ZnO nanocapsule utilizing reliable IV technique. ► Highly efficient photocatalyst for the removal of organic pollutantsZnO nanocapsules have been synthesized hydrothermally. The structural and morophological properties were investigated using X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), FTIR, Raman, EDS and UV–vis absorption spectroscopy. For the first time chemical sensing properties of the synthesized ZnO nanocapsules have been investigated by IV technique, where chloroform is used as a target compound. The chloroform sensors show good sensitivity (0.478 μA cm−2  mM−1), lower detection limit (6.67 μM), and large linear dynamic range (LDR, 12.0 μM–12.0 mM) with good linearity (R, 0.8523) in short response time. Additionally, photocatalytic activity of the prepared capsule shaped ZnO photocatalyst was evaluated by the degradation of acridine orange. Prepared ZnO nanocapsules posses high photocatalytic activity when compared with TiO2-UV100.
Keywords: Nanocapsules; Semiconductor; Chemical synthesis; Photocatalysis; Sensor;

Effect of various lanthanum sol–gel coatings on the 330Cb (Fe–35Ni–18Cr–1Nb–2Si) oxidation at 900 °C by H. Buscail; C. Issartel; F. Riffard; R. Rolland; S. Perrier; A. Fleurentin; C. Josse (678-686).
► We studied the influence of lanthanum sol–gel coatings on a 330Cb alloy oxidation at 900 °C, in air. ► Kinetic results show that coatings lead to a lower oxidation rates. ► Thermal cycling tests show that the oxide scale is adherent on coated specimens.The influence of a lanthanum sol–gel coating on the oxide scale adherence has been studied during the 330Cb (Fe–35Ni–18Cr–1Nb–2Si) oxidation at 900 °C, in air. The alloy oxidation is performed in order to generate a protective chromia scale acting as a good barrier against carburization. Argon annealing of lanthanum sol–gel coatings have been performed at various temperatures in order to find the best conditions to insure the scale adherence. Kinetic results show that lanthanum sol–gel coatings lead to a lower oxidation rate compared to blank specimens. Thermal cycling tests on lanthanum the sol–gel coated specimen show that the oxide scale formed at 900 °C, in air, is adherent.
Keywords: Oxidation; Lanthanum; Sol–gel coating; In situ XRD; Alloy 330Cb; Fe–35Ni–18Cr–1Nb–2Si;

► We studied the effect of ZnO under layers on crystal structure of TiN thin films. ► Double-layered coatings consisting of ZnO/TiN were deposited by magnetron sputtering. ► The ZnO/TiN coatings exhibited TiN{1 0 0} preferred orientation. ► This TiN crystal growth should be caused by ZnO{0 0 1} crystal lattice planes.The effect of ZnO under layers on crystal growth of TiN thin films was investigated. TiN single layers and double-layered ZnO/TiN thin films were deposited on soda-lime-silicate glass substrates by magnetron sputtering. XRD analysis indicated that TiN single layers exhibited {1 1 1} preferred orientation on glass substrates; on the other hand, the TiN thin films with {1 0 0} preferred orientation were obtained using ZnO under layers and crystallized better than the TiN single layers. This crystal orientation change of TiN thin films should come from heteroepitaxial-like growth because the TiN{1 0 0} and ZnO{0 0 1} crystal lattice planes have similar atomic arrangements. Besides, the possible mismatch between TiN and ZnO atomic arrangements was estimated to be 7.8%. Furthermore, the resistivity and optical absorbance of TiN thin films decreased when they were deposited on ZnO under layers. It can be considered that electrical and optical properties should be improved due to the well-crystallization of TiN thin films using ZnO under layers.
Keywords: Sputtering; Thin film; TiN; X-ray diffraction; ZnO;

Study on oxygen source and its effect on film properties of ZnO deposited by radio frequency magnetron sputtering by Yudai Kamada; Mamoru Furuta; Takahiro Hiramatsu; Toshiyuki Kawaharamura; Dapeng Wang; Shin-ichi Shimakawa; Chaoyang Li; Shizuo Fujita; Takashi Hirao (695-699).
► Sputtered ZnO films are mainly formed by a chemical reaction of Zn with oxygen. ► ZnO changed O-rich to Zn-rich with decreasing rf-power and oxygen partial pressure. ► Broad PL emission was observed when the ZnO changed from O-rich to Zn-rich. ► Origin of broad PL emission thought to be an increase of oxygen vacancies. ► Chemical stoichiometry will help us to understand formation of intrinsic defects in ZnO.The structural and optical properties of ZnO thin films deposited at various oxygen partial pressure and rf-power of rf magnetron sputtering were investigated. The sputtered ZnO films are mainly formed with the oxygen which was supplied from a sputtering gas; therefore the film stoichiometry can be controlled by the oxygen partial pressure and rf-power. From photoluminescence study, it was found that the wide emission band above 550 nm was observed due to an increase of oxygen vacancies when the ZnO film changed from O-rich to Zn-rich. The chemical stoichiometry of the film will help us to understand the formation mechanism of intrinsic defects in ZnO films.
Keywords: Zinc oxide; Sputtering; Oxygen partial pressure; rf-power; Thermal desorption spectroscopy (TDS); Photoluminescence (PL); Atomic force microscope (AFM);

► We studied influence of annealing treatment on microstructure and mechanical property of cold sprayed 304SS coatings. ► Annealing treatment changes the anisotropy microstructure of the as-sprayed coating to a uniform equiaxed grain microstructure. ► Annealing treatment changes the weakly mechanical bonded interfaces to metallurgical bonding. ► Annealing treatment significantly increased the tensile strength of the coatings from 67 MPa to 357 MPa. ► Annealing treatment changes the coatings mechanical performance from brittle type to plastic type.In this study, 304 stainless steel coatings were deposited on interstitial-free steel substrate by cold spraying method. The effect of annealing treatment on microstructure, microhardness, ultimate tensile strength and fracture performance of the coatings were studied. The results showed that annealing treatment had made a dominant contribution to heal up the incomplete interfaces between the deposited particles. Both of the microstructure and the mechanical properties have been obviously optimized by annealing treatment. In addition, the coating microhardness decreased from 345 HV0.2 for the as-sprayed coating to 201 HV0.2 for the annealed coating. The coating ultimate tensile strength increased from 65 MPa for the as-sprayed coating to 357 MPa for the annealed coating, which resulted from the increase of the metallurgically bonded areas in the coating induced by annealing treatment. Fracture morphology of the coatings also revealed that annealing treatment changed the fracture character of the cold sprayed 304 stainless steel coating from brittle type to plastic type.
Keywords: Cold spraying; Mechanical property; 304 stainless steel coatings; Microstructure; Annealing treatment;

Density functional study of TaSi n (n  = 1–3, 12) clusters adsorbed to graphene surface by Ping Guo; Lin Zheng; Ji Ming Zheng; Ruizhi Zhang; Luna Yang; Zhaoyu Ren (705-710).
► TaSi n clusters on graphene surface keep its free ground-state structures. ► Graphene is helpful to a linear TaSi2 and a planar TaSi3 form their ground-state structures. ► The configurations of TaSi n cluster on graphene are dominated by the interaction between Ta and graphene. ► For TaSi n /graphene (n  = 1and 2) system, charge transfers mainly from cluster to graphene surface, then from graphene to cluster as n  ≧ 3. ► Chemisorption is dominant for TaSi and TaSi2 on graphene surface, while physisorption for TaSi n (n  ≧ 3) clusters.A plane-wave density functional theory (DFT) calculations have been performed to investigate structural and electronic properties of TaSi n (n  = 1–3, 12) clusters supported by graphene surface. The resulting adsorption structures are described and discussed in terms of stability, bonding, and electron transfer between the cluster and the graphene. The TaSi n clusters on graphene surface favor their free-standing ground-state structures. Especially in the cases of the linear TaSi2 and the planar TaSi3, the graphene surface may catalyze the transition of the TaSi n clusters from an isomer of lower dimensionality into the ground-state structure. The adsorption site and configuration of TaSi n on graphene surface are dominated by the interaction between Ta atom and graphene. Ta atom prefers to adsorb on the hollow site of graphene, and Si atoms tend to locate on the bridge site. Further, the electron transfer is found to proceed from the cluster to the surface for n  = 1 and 2, while its direction reverses as n  > 2. For the case of TaSi, chemisorption is shown to prevail over physisorption as the dominant mode of surface–adsorbate interaction by charge density analysis.
Keywords: Adsorption; Density functional calculations; TaSi n clusters; Graphene;

Shuttle-like ZnO nano/microrods: Facile synthesis, optical characterization and high formaldehyde sensing properties by Lexi Zhang; Jianghong Zhao; Jianfeng Zheng; Li Li; Zhenping Zhu (711-718).
► Shuttle-like ZnO nano/microrod sensors show good formaldehyde sensing performance. ► Formaldehyde can be distinguished from acetaldehyde with a selectivity of about 3. ► The high sensitivity is attributed to donor defects and chemisorbed O2− species.Shuttle-like ZnO nano/microrods were successfully synthesized via a low temperature (80 °C), “green” (without any organic solvent or surfactant) and simple hydrothermal process in the solution of zinc chloride and ammonia water. X-ray diffraction and Raman spectroscopy indicated that the ZnO nano/microrods are a well-crystallized hexagonal wurtzite structure. Yet photoluminescence analysis showed that abundant intrinsic defects (52.97% electron donor defects and 45.49% electron acceptor defects) exist on the surface of ZnO crystals. Gas sensors based on the shuttle-like ZnO nano/microrods exhibited high sensitivity, rapid response–recovery and good selectivity to formaldehyde in the range of 10–1000 ppm at an optimum operating temperature of 400 °C. Through applying linear fitting to the plot of sensitivity versus formaldehyde concentration in logarithmic forms, the chemisorbed oxygen species on the ZnO surface were found to be O2− (highly active among O2, O2 and O species). Notably, formaldehyde can be easily distinguished from acetaldehyde with a selectivity of about 3. The high formaldehyde sensitivity is mainly attributed to the synergistic effect of abundant electron donor defects (52.97%) and highly active oxidants (surface adsorbed O2− species) co-existed on the surfaces of ZnO.
Keywords: ZnO nano/microrods; Photoluminescence; Formaldehyde sensor; Defects; Oxygen species;

Thermal behavior and catalytic activity in naphthalene destruction of Ce-, Zr- and Mn-containing oxide layers on titanium by Marina S. Vasilyeva; Vladimir S. Rudnev; Florian Wiedenmann; Svetlana Wybornov; Tatyana P. Yarovaya; Xin Jiang (719-726).
► Mn-, Ce- and Zr-containing coatings on titanium as catalyst obtained by plasma electrolytic oxidation. ► Catalysts show activity in naphthalene degradation. ► Ce- and Zr-containing coatings have sufficiently high thermal stability until 850 °C.The present paper is devoted to studies of the composition and surface structure, including those after annealing at high temperatures, and catalytic activity in the reaction of naphthalene destruction of Ce-, Zr- and Mn-containing oxide layers on titanium obtained by means of the plasma electrolytic oxidation (PEO) method. The composition and structure of the obtained systems were investigated using the methods of X-ray phase and energy dispersive analysis and scanning electron microscopy (SEM). It was demonstrated that Ce- and Zr- containing structures had relatively high thermal stability: their element and phase compositions and surface structure underwent virtually no changes after annealing in the temperature range 600–800 °C. Annealing of Ce- and Zr-containing coatings in the temperature range 850–900 °C resulted in substantial changes of their surface composition and structure: a relatively homogeneous and porous surface becomes coated by large pole-like crystals. The catalytic studies showed rather high activity of Ce- and Zr-containing coatings in the reaction of naphthalene destruction at temperatures up to 850 °C. Mn-containing structures of the type MnO x  + SiO2  + TiO2/Ti have a well-developed surface coated by “nano-whiskers”. The phase composition and surface structure of manganese-containing layers changes dramatically in the course of thermal treatment. After annealing above 600 °C nano-whiskers vanish with formation of molten structures on the surface. The Mn-containing oxide systems demonstrated lower conversion degrees than the Ce- and Zr-containing coatings, which can be attributed to substantial surface modification and formation of molten manganese silicates at high temperatures.
Keywords: Plasma electrolytic oxidation; Titanium; Coating; Cerium–zirconium oxides; Manganese oxides; Surface structure; Naphthalene destruction;

► Co-deposition of RF-sputtering and RF-PECVD was reported for growing Cu–Ni nanoparticles in a-C:H from acetylene and Cu and Ni targets at room temperature with any harmful chemical reaction. ► The variation of LSPR peak and conductivity of samples were correlated and assigned to surface electron delocalization of Cu NPs. ► The surface morphology of the samples was described by a two dimensional Gaussian self-affine fractal, except the sample with 10 nm thickness of Ni over layer, which is in the nonmetal–metal transition region.We report optical and electrical properties of Cu–Ni nanoparticles in hydrogenated amorphous carbon (Cu–Ni NPs @ a-C:H) with different surface morphology. Ni NPs with layer thicknesses of 5, 10 and 15 nm over Cu NPs @ a-C:H were prepared by co-deposition of RF-sputtering and RF-Plasma Enhanced Chemical Vapor Deposition (RF-PECVD) from acetylene gas and Cu and Ni targets. A nonmetal–metal transition was observed as the thickness of Ni over layer increases. The surface morphology of the sample was described by a two dimensional (2D) Gaussian self-affine fractal, except the sample with 10 nm thickness of Ni over layer, which is in the nonmetal–metal transition region. X-ray diffraction profile indicates that Cu NPs and Ni NPs with fcc crystalline structure are formed in these films. Localized Surface Plasmon Resonance (LSPR) peak of Cu NPs is observed around 600 nm in visible spectra, which is widen and shifted to lower wavelengths as the thickness of Ni over layer increases. The variation of LSPR peak width correlates with conductivity variation of these bilayers. We assign both effects to surface electron delocalization of Cu NPs.
Keywords: Nanostructures; Vacuum deposition; Atomic Force Microscopy (AFM); Grazing incidence X-ray diffraction; Electrical properties; Optical properties;

Nickel plating graphite nanosheets (Ni/GNs) were prepared by electroless plating method using graphite nanosheets (GNs). Then a novel polymer magnetic composites based on acrylate pressure-sensitive adhesive (acrylate PSA) filled with Ni/GNs were fabricated by solution blend method. The Ni/GNs and acrylate PSA/Ni/GNs composites were characterized by scanning electron microscope (SEM)/energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and transmission electron microscope (TEM). All results showed that relatively uniform and compact Ni layer is successfully coated onto GNs under the given conditions, furthermore, Ni/GNs are homogeneously dispersed in acrylate PSA. The VSM results showed that the saturation magnetization of acrylate PSA/Ni/GNs composites increases with an increasing content of Ni/GNs while the coercivity decreases with an increasing content of Ni/GNs. When the content of GNs is 20 wt%, acrylate PSA/Ni/GNs composites exhibites good mechanical properties.
Keywords: Nickel plating graphite nanosheets; Acrylate pressure-sensitive adhesive; Magnetic properties; Mechanical properties;

Display Omitted► CNTs cathode array was screen-printed by independent slurry. ► RIE etching was carried to expose and align more CNTs on cathode surface. ► Hydrogen plasma treatment was introduced to form nanoparticles on CNT wall. ► RIE etching treatment can effectively decrease operating voltage of CNTs cathode. ► Hydrogen plasma treatment can improve uniformity field emission of CNTs cathode.Selective plasma etching and hydrogen plasma treatment were introduced in turn to improve field emission characteristics of screen-printed carbon nanotubes (CNTs) cold cathode, which was prepared by using slurry of mixture of multi-wall CNTs, organic vehicles and inorganic binder, i.e. silicon dioxide sol. The results show that selective plasma etching process could effectively remove parts of surface inorganic vehicle (SiO2) layer and expose more smooth and clean CNTs on cathode surface, which could significantly decrease the operating field of CNTs cathode. There are some nanoparticles emerging on the out of CNTs wall after hydrogen plasma treatment, which are equivalent to increase field emission point of cathode. At the same time, these nanoparticles can increase the local electric field of CNTs, which can decrease operating voltage of CNTs cathode and improve uniformity field emission.
Keywords: Field emission; Carbon nanotubes (CNTs); Post treatment;

Hydrogen species within the metals: Role of molecular hydrogen ion H2 + by Kȩstutis Juodkazis; Jurga Juodkazytė; Asta Grigucevičienė; Saulius Juodkazis (743-747).
Hydrogen storage inside metals is explained based on the first principles.Display Omitted► Novel mechanism of H2 interaction with outer and inner surface of transition metals. ► The inner surface concept is presented for the adsorption of permeable hydrogen species. ► Adsorbed hydrogen molecular ion H2 + as intermediate in H2 molecule dissociative ionization. ► Inner surface of metal phase is available only for H2 + and H+ ions. ► Hydrogen species within metals–ionic pair type hydrogen metallides H2 +  · Me and H+  · Me adsorbed on the inner surface.Novel mechanism of hydrogen interaction with transition metals via stepwise reversible dissociative ionization of H2 molecule is proposed instead of a commonly accepted dissociative adsorption. It involves ionization of H2 to molecular ion ( H 2 + ) ad on the outer surface of metal phase, its subsequent absorption and dissociation within the metal phase into ( H + ) ab ions, i.e., absorbed protons, as described by: H 2 ⇄ ( H 2 + ) ad + e − and ( H 2 + ) ad ⇄ ( H 2 + ) ab ⇄ 2 ( H + ) ab + e − . Absorption here is treated as adsorption on the inner surface of the tetrahedral and octahedral voids within metal lattice. The mechanism is based on the first principles and explains consistently the dependence of mechanical properties of metals on the amount of absorbed hydrogen as well as the mechanism of hydrogenation and hydrogen transport through the metals. The proposed dissociative ionization mechanism is well supported by thermodynamic and steric arguments. In the case of noble metals the presented mechanism carries versatile character as it is valid for both gaseous phase and aqueous solutions.
Keywords: Hydrogen; Molecular ion; Adsorption; Absorption; Transition metals; Inner surface; Proton;

We report a simple technique of selective gold nano-patterning on non-planar polycarbonate substrate by combining nanoimprinting and gold nanotransfer printing techniques in a single concurrent nano-patterning process: thermal nanoimprinting directly patterns a MPTMS (3-mercaptopropyl trimethoxysilane)-coated polycarbonate sheet to form the non-planar nanostructures using a gold-film deposited mold. Simultaneously, the gold-film from the mold is selectively transfer-printed either onto the protrusion or the base of the imprinted non-planar structures. This high nano-patterning selectivity is achieved due to a combined effect of a thiol-terminated MPTMS–gold surface chemistry, more importantly, aided by a surface area dependent differential work of adhesion. We show the high delineation of the patterned gold on the non-planar polycarbonate substrate of various geometries such as pillars, dimples, and gratings, down to nano-scale resolution (130 nm) as well as over micro-scale resolution (10 μm), thus demonstrating that this can be a generic metal patterning technique. Using this technique, we fabricate a metal nanowire grid polarizer to demonstrate a potential device application. The main advantage of this technique lies in its inherent self-aligned process that simplifies selective Au nano-patterning on non-planar polymer surfaces, which is otherwise difficult to be obtained using conventional patterning techniques.
Keywords: Nanoimprinting; Nano-transferprinting; Gold nano-pattern; Self-assembled monolayer; Work of adhesion; Non-planar polymer; Flexible substrate; Self-aligned;

Chemically induced graft copolymerization of 2-hydroxyethyl methacrylate onto polyurethane surface for improving blood compatibility by Chunli He; Miao Wang; Xianmei Cai; Xiaobo Huang; Li Li; Haomiao Zhu; Jian Shen; Jiang Yuan (755-760).
.Display Omitted► A facile and highly efficient approach for surface modification of polyurethane was introduced. ► The films grafted with HEMA monomers might have a potential usage for biomedical applications.To improve hydrophilicity and blood compatibility properties of polyurethane (PU) film, we chemically induced graft copolymerization of 2-hydroxyethyl methacrylate (HEMA) onto the surface of polyurethane film using benzoyl peroxide as an initiator. The effects of grafting temperature, grafting time, monomer and initiator concentrations on the grafting yields were studied. The maximum grafting yield value was obtained 0.0275 g/cm2 for HEMA. Characterization of the films was carried out by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), water contact angle measurements. ATR-FTIR data showed that HEMA was successfully grafted onto the PU films surface. Water contact angle measurement demonstrated the grafted films possessed a relatively hydrophilic surface. The blood compatibility of the grafted films was preliminarily evaluated by a platelet-rich plasma adhesion test and hemolysis test. The results of platelet adhesion experiment showed that polyurethane grafted polymerization with monomer of 2-hydroxyethyl methacrylate had good blood compatibility featured by the low platelet adhesion. Hemolysis rate of the PU-g-PHEMA films was dramatically decreased than the ungrafted PU films. This kind of new biomaterials grafted with HEMA monomers might have a potential usage for biomedical applications.
Keywords: Polyurethane; Surface modification; Graft polymerization; Blood compatibility; 2-Hydroxyethyl methacrylate;

Fabrication of superhydrophobic wood surfaces via a solution-immersion process by Changyu Liu; Shuliang Wang; Junyou Shi; Chengyu Wang (761-765).
The polymethylsilsesquioxane thereby became covalently bound to the surface of the wood through a polycondensation reaction under heat condition.Display Omitted► Potassium methyl siliconate was utilized to fabricate superhydrophobic wood surface. ► The method involves a hydrogen bond assembly and a polycondensation process. ► The wood surface was superhydrophobic with water contact angle larger than 150°.Superhydrophobic wood surfaces were fabricated from potassium methyl siliconate (PMS) through a convenient solution-immersion method. The reaction involves a hydrogen bond assembly and a polycondensation process. The silanol was formed by reacting PMS aqueous solution with CO2, which was assembled on the wood surface via hydrogen bonds with the wood surface –OH groups. The polymethylsilsesquioxane coating was obtained through the polycondensation reaction of the hydroxyl between wood and silanol. The morphology of products were characterized using a scanning electron microscope (SEM), the surface chemical composition was determined using energy dispersive X-ray analysis (EDXA), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry (TGA) and contact angle measurement. Analytical results revealed that rough protuberances uniformly covered the wood surface, thus transforming the wood surface from hydrophilic to superhydrophobic. The water contact angle of the superhydrophobic wood surface was about 153° and a sliding angle was 4.6°.
Keywords: Superhydrophobic; PMS; Wood; Surface; Coating;

Improving the surface properties of multi-walled carbon nanotubes after irradiation with gamma rays by B. Safibonab; A. Reyhani; A. Nozad Golikand; S.Z. Mortazavi; S. Mirershadi; M. Ghoranneviss (766-773).
► Surface properties of irradiated MWCNTs were studied by different doses of γ ray. ► The results showed that γ irradiation affected the structure and morphology of MWCNTs. ► Irradiated MWCNTs exhibited a larger specific surface area compared with the raw MWCNTs. ► γ irradiation with the absorbed dose of 150 kGy destroyed the nanostructure of carbons.The effects of gamma-irradiation on the modification of the surface and structure of multi-walled carbon nanotubes were studied. Gamma-irradiation affected the graphitization properties of functional groups, and decreased the diameter of multi-walled carbon nanotubes. The irradiated multi-walled carbon nanotubes with the absorbed dose of 100 kGy exhibited a larger specific surface area and microporous volume as compared with the other samples. The Raman spectroscopy and X-ray photoelectron spectroscopy showed that the interaction between the gamma-irradiation and the multi-walled carbon nanotubes with the absorbed dose of 150 kGy destroyed the nanostructure of carbons, leading to the formation of diamond-like structures and carbon oxides. In addition, gamma-irradiation with the absorbed dose of 100 kGy improved multi-walled carbon nanotubes graphitization and surface properties while at higher absorbed dose (150 kGy), it induced damaged structures (sp3 bonds and oxygen compositions).
Keywords: Gamma-ray irradiation; Multi-walled carbon nanotubes; Surface properties; Raman spectroscopy; XPS;

Laser micro/nano patterning of hydrophobic surface by contact particle lens array by Ashfaq Khan; Zengbo Wang; Mohammad A. Sheikh; David J. Whitehead; Lin Li (774-779).
► A method for transporting a monolayer array of 1 micron particles is developed. ► Patterning of hydrophobic surfaces is carried out for the first time. ► Coupled electromagnetic and thermal modelling is used for understanding process. ► Experimentation to generate features beyond diffraction limit. ► Repeated use of Contact particles is carried out for the first time.Direct laser surface micro/nanopatterning by using Contact Particle Lens Array (CPLA) has been widely utilized. The method involves laser scanning of a monolayer of transparent particles arranged on the substrate to be patterned. Despite the different techniques available for CPLA deposition; the particles monolayer can only be formed on hydrophilic surfaces, which restrict the range of substrates that could be patterned by this method. In this study, a technique for patterning of hydrophobic surfaces by using CPLA has been proposed. In the proposed technique, monolayer of CPLA is formed on a hydrophilic substrate and then transported to a hydrophobic substrate by using a flexible sticky plastic. The transported CPLA is then scanned by a laser for patterning the hydrophobic substrate. The plastic pre-selected for this work was transparent to the laser. Experimental investigations were carried out to generate bumps and bowl shaped patterns using transported particles. Features smaller than the diffraction limit have been generated. The optical near field and associated temperatures around the particles were numerically simulated with a coupled electromagnetic and thermal modelling technique.
Keywords: Laser micro/nano patterning; Hydrophobic surface; CPLA; Optical near-field;

XPS and UPS study on band alignment at Pt–Zn-terminated ZnO(0 0 0 1) interface by Petr Blumentrit; Michiko Yoshitake; Slavomír Nemšák; Taeyoung Kim; Takahiro Nagata (780-785).
► We prepared platinum–zinc terminated zinc oxide interface by platinum deposition. ► XPS core level shifts and band bending were investigated. ► Platinum deposition leads to zinc oxide surface reduction and platinum oxide formation. ► We determined band alignment of the Pt–ZnO interface determination.The interface between Pt and Zn-terminated ZnO(0 0 0 1) was investigated by X-ray and ultra violet photoelectron spectroscopy in order to examine electronic band alignment. An angle-resolved X-ray photoelectron spectroscopy measurement of the clean ZnO(0 0 0 1) surface has revealed a downward band bending by 0.25 eV. The results of the valence band analysis show that the work function and the valence band maximum of clean ZnO(0 0 0 1) were 4.49 eV and 2.79 eV, respectively. Platinum was then deposited in several deposition steps onto a clean ZnO(0 0 0 1) surface up to 0.6 nm in thickness. After the deposition, the binding energy of Zn 2p doublet peak was shifted towards lower value by 0.77 eV, and the measured work function changed to 5.51 eV. As a result, the Schottky barrier height of Pt/ZnO(0 0 0 1) interface was 1.11 eV.
Keywords: Zinc oxide; Platinum oxide; Band bending; Schottky barrier height;

New surface-modified zinc oxide nanoparticles with aminotriethylene oxide chains linked by 1,2,3-triazole ring: Preparation, and visible light-emitting and noncytotoxic properties by Moriyuki Sato; Kanako Shimatani; Yuko Iwasaki; Shigekazu Morito; Hidekazu Tanaka; Yasuhisa Fujita; Morihiko Nakamura (786-790).
► Surface-modified ZnO NPs (ZPAZ) with aminotriethylene oxide chains linked by 1,4- and/or 1,5-disubstituted 1,2,3-triazole rings were prepared via azide/alkyne click reaction by heating without Cu(I) catalyst. ► The resulting ZPAZ particles had nanostructured sizes below 6 nm and showed a broad visible emission band due to trapped-electron emission. ► It was demonstrated that the ZPAZ NPs are noncytotoxic and almost all RAW264.7 cells are alive after 24 h of treatment. ► The application of ZPAZ NPs to biological imaging and labeling probes will pave the way to develop novel diagnostic strategies for intractable diseases.Novel surface-modified, visible light-emitting and noncytotoxic ZnO nanoparticles (NPs) (ZPAZ) having aminotriethylene oxide chains linked by 1,4- and/or 1,5-disubstituted 1,2,3-triazole rings were prepared from ZnO NPs (ZPA) with ethynyl groups on the surfaces and an azide derivative of triethylene oxide chain linking terminal amino group (ATA) via 1,3-dipolar azide/alkyne click reaction by heating without Cu(I) catalyst. FTIR spectroscopy, elemental analysis, XRD analysis and TEM observation suggested that the resulting ZPA and ZPAZ NPs have the particle sizes below 10 nm in diameters, triethylene oxide chains linking the terminal amino groups and wurtzite crystal structure. UV–vis absorption spectrum of the ZPAZ NPs in methanol showed maximum absorption band at 346.5 nm, supporting the TEM observation. PL spectra depicted that the ZPA and ZPAZ NPs display broad light green and lightly greenish yellow visible light emitting bands in methanol. Zeta potentials measured in distilled water suggested that the ZPAZ NPs have a low tendency to aggregate and possess better stability than the ZPA NPs. Cytotoxicity assay revealed that the ZPAZ NPs, having water-dispersion properties, are noncytotoxic at low concentrations and almost all RAW264.7 cells are alive after 24 h of treatment.
Keywords: ZnO nanoparticles; Surface-modification; Visible light-emission; Zeta potential; Noncytotoxicity; Azide/alkyne click reaction;

► Nanocrystalline CNx:H films are prepared via pyrolysis of ethylenediamine. ► Some N atoms incorporate into the crystal lattice of graphite to form CNx compound. ► Increasing temperature adds to formation of C=N bond and improved wear resistance. ► Nanocrystal CNx:H film prepared at 900 °C has optimal friction and wear behavior.Hydrogenated-carbon nitride (CN x :H) films were synthesized on silicon substrate in a large quantity by the pyrolysis of ethylenediamine in a temperature range of 700–950 °C. The influence of temperature on the morphology, structure, adhesion to substrate, and friction and wear behavior of CN x :H films was investigated. It has been found that CN x :H films obtained at 700 °C and 800 °C are amorphous, and those prepared at 900 °C and 950 °C consist of carbon nitride nanocrystal. Besides, CN x :H film sample obtained at 700 °C has the maximum N content of 9.1 at.% but the poorest adhesion to Si substrate, while the one prepared at 900 °C has the lower N content and the highest adhesion to substrate. As a result, nanocrystalline CN x :H (nc-CN x :H) film synthesized at 900 °C possesses the best wear resistance when slides against stainless steel counterpart. N atom is incorporated into the graphitic network in three different bonding forms, and their relative content is closely related to temperature, corresponding to different adhesion as well as friction and wear behavior of the films obtained at different temperatures. Furthermore, the friction coefficient and antiwear life of as-deposited CN x :H films vary with varying deposition temperature and thickness, and the film with thickness of 1.3 μm, obtained at 900 °C, has the longest antiwear life of over 180,000 s.
Keywords: Silicon substrate; CN x :H film; Temperature; Structure; Adhesion; Friction and wear behavior;

► We observe that the adsorption of Sb atoms on graphene is similar to the adsorption of Bi atoms. There exists a weak physisorption. ► We distorted the graphene lattice by removing C atom and changing lattice parameter, we observe the chemisorption. ► The additional adsorption of Li atoms change the electronic band structure of the system. Li atoms may tend to form clusters on the graphene surface.We have investigated the Sb and Sb2 doping of graphene and the effect of Li n (n  = 2–4) atoms in detail. We find chemisorption only when we replace C with Sb and Sb2 and distort the lattice. The additional adsorption of Li atoms changes the electronic band structure of the system.
Keywords: First Principle; Adsorption on graphene; Antimony;

Fabrication of superhydrophobic wood surface by a sol–gel process by Shuliang Wang; Changyu Liu; Guochao Liu; Ming Zhang; Jian Li; Chengyu Wang (806-810).
The superhydrophobic coatings were fabricated on the wood surface through the combination of silica nanoparticles that created surface roughness and a subsequent surface modification with 1H, 1H, 2H, 2H- perfluoroalkyltriethoxysilanes (POTS) reagent, and the obtained superhydrophobic wood surface shows a large contact angle of 164°and sliding angle less than 3°.Display Omitted► The superhydrophobic wood surface was obtained via a sol–gel process of TEOS followed by a fluorination treatment of POTS. ► The silica nanoparticles deposited on the wood surface by the chemical bond between hydroxyl groups of wood surface and silica particles. ► POTS molecules combine with silica nanoparticles in the forming of covalent bond. ► The superhydrophobic treatment has transformed the wood surface from hydrophilic to superhydrophobic: the water CA of 164o and sliding angle less than 3o. ► The superhydrophobic wood surface shows a good stability in the air.The superhydrophobic wood surface was fabricated via a sol–gel process followed by a fluorination treatment of 1H, 1H, 2H, 2H- perfluoroalkyltriethoxysilanes (POTS) reagent. The crystallization type of silica nanoparticles on wood surface was characterized using X-ray diffraction (XRD), the microstructure and chemical composition of the superhydrophobic wood surface were described by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS), the bonding force between the silica nanoparticles and POTS reagent was analyzed by Fourier transform infrared spectroscopy (FT-IR) and the superhydrophobic property of the treated sample was measured by contact angle (CA) measurements. An analytical characterization revealed that nanoscale silica spheres stacked uniformly over the wood surface, and with the combination of the high surface roughness of silica nanoparticles and the low surface free energy film of POTS on wood surface, the wood surface has turned its wetting property from hydrophilic into superhydrophobic with a water contact angle of 164° and sliding angle less than 3°.
Keywords: Superhydrophobic; Silica nanoparticles; Sol–gel process; Wood surface;

► Significant effect of interface roughness on the surface cracking behavior in film/substrate system. ► Oscillatory distributions of strain energy release rate. ► Surface cracking in the film can be arrested locally. ► Rough interface can enhance the durability of film/substrate system with multiple cracks.The objective of this work is to understand the effect of interface roughness on the strain energy release rate and surface cracking behavior in air plasma sprayed thermal barrier coating system. This is achieved by a parameter investigation of the interfacial shapes, in which the extended finite element method (XFEM) and periodic boundary condition are used. Predictions for the stress field and driving force of multiple surface cracks in the film/substrate system are presented. It is seen that the interface roughness has significant effects on the strain energy release rate, the interfacial stress distribution, and the crack propagation patterns. One can see the completely different distributions of stress and strain energy release rate in the regions of convex and concave asperities of the substrate. Variation of the interface asperity is responsible for the oscillatory characteristics of strain energy release rate, which can cause the local arrest of surface cracks. It is concluded that artificially created rough interface can enhance the durability of film/substrate system with multiple cracks.
Keywords: Interface roughness; Strain energy release rate; Surface crack; Film; Substrate; Extended finite element method;

A study of the optical properties and adhesion of zinc sulfide anti-reflection thin film coated on a germanium substrate by S.A.R. Firoozifar; A. Behjat; E. Kadivar; S.M.B. Ghorashi; M. Borhani Zarandi (818-821).
► ZnS antireflection coating on Ge substrate is studied. ► We examine changes of optical transmittance versus deposition rates. ► Annealing enhances the transmittance of the samples. ► Annealing and deposition rate effects improve the adhesion of the ZnS to the Ge substrate.To conduct this study, zinc sulfide (ZnS) thin films deposited on germanium (Ge) substrates were prepared by an evaporation method. The effects of deposition rate and annealing on the optical properties and adhesion of the ZnS thin films were investigated. The transmission intensity and the X-ray diffraction (XRD) pattern of the samples showed that the transmittance of the samples decreases by increasing the evaporation rates. However, with the increase of the annealing temperature, crystallinity of the thin films improves which, in turn, results in the enhancement of the transmission intensity in a far infrared region. The maximum grain size was obtained at the annealing temperature of 225 °C. Our experimental results also show that evaporation rate and annealing influences the adhesion of ZnS thin films to Ge substrates.
Keywords: Annealing; Optical properties; ZnS; Antireflection; Adhesion; Ge;

► A novel ∼1 wt.%Bi-containing brass film was developed. ► Adding Bi increased corrosion resistance of brass film in K2SO4 solution. ► Adding Bi prevented cracking of brass film.A single phase Cu–Zn–Bi film is fabricated on the steel wire by electrodeposition. Bi addition (∼1 wt.%) greatly increases the corrosion resistance of brass (Cu−36 wt.% Zn) film in a 0.05 M K2SO4 solution as shown by potentiodynamic polarization and electrochemical impendence spectroscopy (EIS) experiments. It is proposed that the main reason for the improvement in the corrosion resistance by the Bi addition is that it greatly increased the crack resistance, which thus prevents crack-induced galvanic corrosion occurring between the brass film and the steel substrate.
Keywords: Bi; Brass; Electrodeposition; Crack; Corrosion;

Crystal morphology variation in inkjet-printed organic materials by Andrew C. Ihnen; Anne M. Petrock; Tsengming Chou; Phillip J. Samuels; Brian E. Fuchs; Woo Y. Lee (827-833).
► Explosive crystal morphology can be substantially varied by altering ink deposition parameters. ► Ink evaporation rate and microfluidic ink droplet confinement of nucleating phases drive morphology development. ► Explosive crystal size ranging from ∼300 nm to 1 mm produced, depending on deposition parameters. ► Energetic composite materials can be deposited with a lateral spatial resolution of ∼50 μm.The recent commercialization of piezoelectric-based drop-on-demand inkjet printers provides an additive processing platform for producing and micropatterning organic crystal structures. We report an inkjet printing approach where macro- and nano-scale energetic composites composed of cyclotrimethylenetrinitramine (RDX) crystals dispersed in a cellulose acetate butyrate (CAB) matrix are produced by direct phase transformation from organic solvent-based all-liquid inks. The characterization of printed composites illustrates distinct morphological changes dependent on ink deposition parameters. When 10 pL ink droplets rapidly formed a liquid pool, a coffee ring structure containing dendritic RDX crystals was produced. By increasing the substrate temperature, and consequently the evaporation rate of the pooled ink, the coffee ring structure was mitigated and shorter dendrites from up to ∼1 to 0.2 mm with closer arm spacing from ∼15 to 1 μm were produced. When the nucleation and growth of RDX and CAB were confined within the evaporating droplets, a granular structure containing nanoscale RDX crystals was produced. The results suggest that evaporation rate and microfluidic droplet confinement can effectively be used to tailor the morphology of inkjet-printed energetic composites.
Keywords: Inkjet printing; Dendrite; Nanocomposite; RDX;

Preparation of Ga-doped ZnO films by pulsed dc magnetron sputtering with cylindrical rotating target for thin film solar cell applications by Beom-Ki Shin; Tae-Il Lee; Ji-Hyeon Park; Kang-Il Park; Kyung-Jun Ahn; Sung-Kee Park; Woong Lee; Jae-Min Myoung (834-838).
► Pulsed dc magnetron sputtering (PDMS) with a cylindrical rotating target was employed for GZO TCO film. ► It exhibits proper electrical and optical properties for front electrodes of TFSC. ► The 750 nm-thick GZO film shows the best electrical and optical properties. ► Texturing of the film yields an improved light trapping without degradation in electrical properties. ► GZO film prepared by PDMS with rotating cylindrical target can be applied to front electrodes of TFSCs.Applicability of Ga-doped ZnO (GZO) films for thin film solar cells (TFSCs) was investigated by preparing GZO films via pulsed dc magnetron sputtering (PDMS) with rotating target. The GZO films showed improved crystallinity and increasing degree of Ga doping with increasing thickness to a limit of 1000 nm. The films also fulfilled requirements for the transparent electrodes of TFSCs in terms of electrical and optical properties. Moreover, the films exhibited good texturing potential based on etching studies with diluted HCl, which yielded an improved light trapping capability without significant degradation in electrical propreties. It is therefore suggested that the surface-textured GZO films prepared via PDMS and etching are promising candidates for indium-free transparent electrodes for TFSCs.
Keywords: Transparent conductive oxide (TCO); Solar cell; Ga-doped ZnO (GZO); Pulsed dc magnetron sputtering; Cylindrical rotating target; Surface texturing;

Investigations on structural and optical properties of Zn1−x Gd x S nanoparticles by A. Divya; K. Siva Kumar; P.Sreedhara Reddy (839-842).
► We report on the synthesis of Zn1−x Gd x S nanoparticles in aqueous media through a facile and inexpensive synthetic process. ► Influence of Gd concentration on structural and optical properties has been investigated. ► XRD revealed that Zn1−x Gd x S nanoparticles are cubic zincblende structure with an average particle size of 3–5 nm. ► Optical studies showed that incorporation of Gd into ZnS enhanced luminescence intensity with increasing Gd concentration.Zn1−x Gd x S (x  = 0.00, 0.02 and 0.04) nanoparticles were synthesized by facile chemical co-precipitation method using PVP as a surfactant. ZnS nanoparticles could be doped with Gd ions during synthesis without altering the XRD patterns of ZnS. Also, the pattern of the powders showed cubic zincblende structure. The particle size obtained from the XRD studies lies in the range 3–5 nm, whereas from TEM analysis it is 4 nm for x  = 0.02 sample. The UV–Vis absorption spectra revealed that Zn1−x Gd x S nanoparticles exhibit strong confinement effect as the blue shift in the absorption spectra with that of the undoped ZnS. The photoluminescence spectra showed enhanced luminescence intensity and the entry of Gd into host lattice.
Keywords: Zn1−x Gd x S nanoparticles; X-ray diffraction (XRD); Transmission electron microscopy (TEM); Photoluminescence (PL);

Dielectric properties of continuous composition spreaded MgO–Ta2O5 thin films by Yun Hoe Kim; Jong-Han Song; Jin Sang Kim; Seok-Jin Yoon; Kyung Bong Park; Ji-Won Choi (843-847).
► We explored new dielectric compositions and thin films using continuous composition spread. ► MgO and Ta2O5 compound films were deposited on a substrate and high throughput evaluated. ► We found some specific compositions which had high dielectric constant and very low dielectric loss. ► These optimized thin film compositions were processed at low temperature (below 350 °C).The dielectric properties of MgO–Ta2O5 continuous composition spread (CCS) thin films were investigated. The MgO–Ta2O5 CCS thin films were deposited on Pt/Ti/SiO2/Si substrates by off-Axis RF magnetron sputtering system, and then the films were annealed at 350 °C with rapid thermal annealing system in vacuum. The dielectric constant and loss of MgO–Ta2O5 CCS thin films were plotted via 1500 micron-step measuring. The specific point of Ta2O5–MgO CCS thin film (post annealed at 350 °C) showing superior dielectric properties of high dielectric constant (k  ∼ 28) and low dielectric loss (tan  δ  < 0⋅004) at 1 MHz were found in the area of 3–5 mm apart from Ta2O5 side on the substrate. The cation's composition of thin film was Mg:Ta = 0.4:2 at%.
Keywords: High-k; Thin films; Continuous composition spread; RF magnetron sputtering;

► Magnetron sputtering enables deposition of a quasicrystalline AlCuFe coating on titanium alloy. ► AlCuFe coating exhibits higher hardness than the substrate material. ► AlCuFe coating improves oxidation resistance of the TIMETAL 834 alloy at 750 °C.A protective quasicrystalline AlFeCu coating was deposited on TIMETAL 834 substrate by nonreactive magnetron sputtering in order to improve resistance of the alloy to oxidation. Microstructure characterisation of the substrate and the coating was performed by analytical scanning- and transmission electron microscopy as well as X-ray diffractometry. Depending on annealing temperature and time, the deposited coating (2.7 μm thick) has a different microstructure. The coating in Specimen 1 (annealed 600 °C/4 h in vacuum) consisted of two zones: outer, composed of Al5Fe2 and Al2Cu3 phases and inner, in which only quasicrystalline ψ phase was present. The coating in Specimen 2 (annealed 600 °C/4 h + 700 °C/2 h in vacuum) was fully quasicrystalline and consisted of icosahedral ψ phase.Both coatings exhibit higher microhardness than the substrate material. It was established that the applied surface treatment essentially improves oxidation resistance of the alloy tested at 750 °C during 250 h in static air. Sample weight gain was 60% lower than in the case of uncoated sample. Oxide scale spallation occurred for uncoated alloy while the coated one did not show any spallation. It was found that the very brittle scale formed during oxidation on the uncoated alloy was consisting of TiO2, while that on the coated one consisted mainly of α-Al2O3.
Keywords: Titanium alloy; Transmission electron microscopy; Magnetron sputtering; Quasicrystalline coating; Oxidation resistance;

Interfacial bonding characteristic of nanoclay/polymer composites by Mo-lin Chan; Kin-tak Lau; T.T. Wong; Francisco Cardona (860-864).
Display Omitted► FTIR analysis revealed that silicon in nanoclay does react with epoxy. ► FTIR spectrum in nano-composite is assigned to Si–O–R, Si–CH2–R, Si–C and siloxanes. ► XPS analysis proves that C atoms were substituted with O atom, Si atoms and Al atoms. ► The chemical bonding at the interface between the matrix and nanoclay did exist.Using a small amount of nanoclay (montmorillonite (MMT)) can significantly enhance the thermal and mechanical properties of polymer-based composites. Therefore, an in depth understanding of the bonding characteristic between the nanoclay and its surrounding matrix is essential. In this study, Fourier Transform Infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were conducted to analyze the chemical composition between epoxy matrix and nanocomposite. These experiments revealed that a chemical bonding at an interface between the matrix and nanoclay of the composites did exist. Thus, such bonding can enhance the mechanical and thermal properties of resultant polymer composites as reported in many literatures.
Keywords: Fourier Transform Infrared spectroscopy (FTIR); X-ray photoelectron spectroscopy (XPS);

A series of nano ZSM-5 type ferrisilicate catalysts with different compositions were prepared by hydrothermal method. Selective dehydrogenation of ethylbenzene was successfully performed using these ferrisilicates as novel catalysts in the presence of N2O or steam to form styrene. It was found that the formation of ZSM-5 type ferrisilicates, presence of potassium in the precursors and N2O, promoted ethylbenzene dehydrogenation.Display Omitted► Several types of nanosized ZSM-5 type ferrisilicates were prepared by hydrothermal synthesis. ► Characterized using BET measurements, XRD, TEM, SEM-EDS and ICP techniques. ► Catalysts for selective ethylbenzene dehydrogenation to styrene. ► Potassium in the precursors, SiO2/Fe2O3 ratio and N2O play an important role in the reaction. ► K-FZ30 showed high yield of styrene.Nanosized ZSM-5 type ferrisilicates were successfully prepared using hydrothermal process. Several parameters including gel initiative compositions (Na+ or K+ alkali system), SiO2/Fe2O3 molar ratios and hydrothermal temperature were systematically investigated. The samples were characterized by XRD, TEM, SEM-EDS, BET surface area and ICP techniques. It was found that surface areas and the total pore volume increase with increasing in the SiO2/Fe2O3 molar ratio at Na-FZ ferrisilicates. The catalytic performance of the synthesized catalysts was evaluated in ethylbenzene dehydrogenation to styrene in the presence of N2O or steam at temperatures ranging from 400 °C to 660 °C under atmospheric pressure. The effects of gel initiative compositions, SiO2/Fe2O3 molar ratio as well as the hydrothermal synthesis temperature on the catalytic performance of these catalysts have been addressed. It was shown that styrene yield significantly influenced by altering in the SiO2/Fe2O3 ratio but was not greatly influenced by changes in hydrothermal synthesis temperatures. The comparison between performance of potassium and sodium containing catalysts was shown that the one with potassium has higher yield and selectivity toward styrene production at an optimum temperature of 610 °C.
Keywords: Ferrisilicate; Nano ZSM-5; Styrene; Ethylbenzene; Dehydrogenation;

► Al-O films as catalyst-support layer in vertical SWCNT growth using ethanol CVD. ► Investigation of various Al-based catalyst-support layers. ► Thermally oxidized Al-O (400 °C, 10 min, static air) has the most appropriate surface properties for efficient VA-SWCNT growth. ► Surface roughness and surface chemical states of support layer are critical in determining CNT growth performance.Characteristics and role of Al oxide (Al-O) films used as catalyst-support layer for vertical growth of single-walled carbon nanotubes (SWCNTs) were studied. EB-deposited Al films (20 nm) were thermally oxidized at 400 °C (10 min, static air) to produce the most appropriate surface structure of Al-O. Al-O catalyst-support layers were characterized using various analytical measurements, i.e., atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and spectroscopy ellipsometry (SE). The thermally oxidized Al-O has a highly roughened surface, and also has the most suitable surface chemical states compared to other type of Al-O support layers. We suggest that the surface of thermally oxidized Al-O characterized in this work enhanced Co catalyst activity to promote the vertically aligned SWCNT growth.
Keywords: Vertically aligned single-walled CNT; Aluminum oxide support layer; Co catalyst; Ethanol CVD; Al-O surface roughness; Al-O surface chemical state;

Highly adhesive metal plating on Zylon® fiber via iodine pretreatment by Ummul Khair Fatema; Yasuo Gotoh (883-889).
► Iodine pretreatment effectively catalyzed PBO surface for electroless Cu plating. ► Pd particles formed at the fiber surface improved the adhesion of plated layer. ► Plated layer was durable against ultrasonic exposure, tape peel-off and corrosion. ► Plated fiber shows durable electrical conductivity. ► Plated layer protect the mechanical properties of PBO against light degradation.Highly adhesive metal plating was performed on poly(p-phenylene-2,6-benzobisoxazole) fiber named Zylon® via iodine pretreatment followed by electroless plating. First, iodine components were selectively doped into the inner part of the fiber near the surface through iodine vapor exposure. The doped iodine was converted to palladium iodide particles by treating with palladium chloride solution. After the reduction of the iodide to metal palladium particles, electroless copper plating was conducted on the fiber. A uniform copper layer was deposited on the fiber surface and exhibited high durability in durability tests such as ultrasonic exposure, tape peeling-off, and corrosion in NaCl solution. This durability was attributed to the palladium particles formed at the fiber surface that served as an anchor for the plated layer as well as an electroless plating catalyst. The plated fibers also possessed electrical conductivity. Although the tensile strength of the Zylon® fiber decreased from 5.8 to 4.9 GPa after undergoing the pretreatment and plating processes, the light shielding effect improved the light resistance of the plated fibers in terms of tensile properties. After 18 days of xenon lamp exposure, the plated fibers retained 74% of its initial strength, whereas that of untreated fibers decreased to 43%.
Keywords: Iodine; Zylon®; Electroless plating; Conductive fiber; Light resistance fiber;

Quenching of surface traps in Mn doped ZnO thin films for enhanced optical transparency by Usman Ilyas; R.S. Rawat; G. Roshan; T.L. Tan; P. Lee; S.V. Springham; Sam Zhang; Li Fengji; R. Chen; H.D. Sun (890-897).
► First ever use of wet chemical method to prepare ZnO:Mn powders for PLD pellets. ► XRD spectra showed improved crystallinity of ZnO:Mn with post-deposition annealing. ► PL showed enhanced optical transparency and optical band gap in ZnO:Mn thin films by quenching the surface traps in these thin films. ► XPS confirmed the presence of Mn in its Mn2+ and Mn4+ oxidation states in ZnO:Mn thin films. ► FESEM showed well-defined nano-sized grains and smoother surface features in ZnO:Mn thin films at elevated temperatures.The structural and photoluminescence analyses were performed on un-doped and Mn doped ZnO thin films grown on Si (1 0 0) substrate by pulsed laser deposition (PLD) and annealed at different post-deposition temperatures (500–800 °C). X-ray diffraction (XRD), employed to study the structural properties, showed an improved crystallinity at elevated temperatures with a consistent decrease in the lattice parameter ‘c’. The peak broadening in XRD spectra and the presence of Mn 2p3/2 peak at ∼640 eV in X-ray Photoelectron Spectroscopic (XPS) spectra of the doped thin films confirmed the successful incorporation of Mn in ZnO host matrix. Extended near band edge emission (NBE) spectra indicated the reduction in the concentration of the intrinsic surface traps in comparison to the doped ones resulting in improved optical transparency. Reduced deep level emission (DLE) spectra in doped thin films with declined PL ratio validated the quenching of the intrinsic surface traps thereby improving the optical transparency and the band gap, essential for optoelectronic and spintronic applications. Furthermore, the formation and uniform distribution of nano-sized grains with improved surface features of Mn-doped ZnO thin films were observed in Field Emission Scanning Electron Microscopy (FESEM) images.
Keywords: ZnO:Mn thin films; Pulsed laser deposition; Photoluminescence; Surface traps; Optical transparency;

► Composition profile is important for microstructure and mechanical performance. ► We simulate concentration distribution evolution of elements using a self-developed model. ► Different elements have similar concentration distribution patterns. ► Strong convective motion dominates the species transportation in laser cladding. ► The model helps to achieve appropriate microstructure and target mechanical properties.Direct metal deposition (DMD) with coaxial powder injection allows fabrication of three-dimensional geometry with rapidly solidified microstructure. During DMD, addition of powder leads to the interaction between laser and powder, and also the redistribution of solute. The concentration distribution of the alloying element is very important for mechanical properties of the deposited clad material. The evolution of concentration distribution of carbon and chromium in the molten pool is simulated using a self-consistent three-dimensional model, based on the solution of the equations of mass, momentum, energy conservation and solute transport in the molten pool. The experimental and calculated molten pool geometry is compared for model validation purposes.
Keywords: Laser cladding; Solute transport; Composition profile;

XPS and TPD investigation of CO adsorption on mixed Rh–V layers supported by gamma-alumina by Igor Píš; Vladimír Matolín; Václav Nehasil (908-913).
► Mixed Rh–V thin films supported by gamma-alumina as model catalyst. ► CO chemisorption and electronic properties have been studied. ► Strong dependence of the studied properties on preparation conditions. ► Formation of Rh–V alloy is weakening CO-surface bond and increases CO dissociation.Alumina-supported mixed bimetallic Rh–V thin films, with the overall thickness of 0.8 ML, were prepared under the ultrahigh vacuum (UHV) conditions and characterized with respect to their electronic and CO adsorption properties. X-ray photoelectron spectroscopy (XPS) was utilized to characterize electronic changes accompanying bimetallic Rh–V interaction and interaction between metal and polycrystalline γ-Al2O3 substrate. The chemisorption properties were probed by temperature-programmed desorption spectroscopy (TPD) of CO molecules. The electronic and chemisorption properties of the mixed layers were compared with pure Rh and V layers grown on the same γ-Al2O3 substrate and with a model bimetallic Rh–V system prepared by V deposition on a polycrystalline Rh foil. By varying the preparation conditions, we observed a strong dependence of the studied properties on the position of the V atoms. The presence of V atoms on the surface led to a fast deactivation, while vanadium presented under the surface resulted in a weakening of CO-metal surface bond, a change in the proportion of the adsorption side species, and an increase of CO dissociation.
Keywords: Model catalyst; X-ray photoelectron spectroscopy; Temperature programmed desorption; Rhodium; Vanadium; Carbon monoxide;

Fabrication of textured SnO2:F thin films by spray pyrolysis by Yang Ren; Gaoyang Zhao; Yuanqing Chen (914-918).
► SnO2:F films with textured surfaces can be obtained on glasses by spray pyrolysis. ► The influence of film thickness on optical and electrical properties is investigated. ► Increasing film thickness will increase the film conductivity and haze. ► Increasing film thickness will decrease the film total transmittance. ► An optimal 810 nm-thick SnO2:F film with textured surface can be obtained.Transparent conductive SnO2:F thin films with textured surfaces were fabricated on soda–lime–silica glass substrates by spray pyrolysis. Structure, morphology, optical and electrical properties of the films were investigated. Results show that the film structure, morphology, haze, transmittance and sheet resistance are dependent on the substrate temperature and film thickness. An optimal 810 nm-thick SnO2:F film with textured surface deposited at 520 °C exhibits polycrystalline rutile tetragonal structure with a (2 0 0) orientation. The sheet resistance, average transmittance in visible region, and haze of this film were 8 Ω/□, 80.04% and 11.07%, respectively, which are suitable for the electrode used in the hydrogenated amorphous silicon solar cells.
Keywords: Spray pyrolysis; Textured; SnO2; Film; Haze;

Facile synthesis and characterization of SnTe films by Y.Y. Wang; K.F. Cai; X. Yao (919-922).
► SnTe films are deposited on glass substrate at room temperature and ambient pressure. ► The SnTe films were prepared by a chemical bath method. ► The film deposited using polyethyleneglycol as the surfactant is smooth and dense.In this paper, we reported a novel, simple, and cost-effective route to SnTe films. The films were prepared by a chemical bath method, at room temperature and ambient pressure, using conventional chemicals as starting materials with or without surfactant. The films were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and field-emission scanning electron microscopy, respectively. The SnTe film deposited without surfactant consists of nanoparticles (∼100 nm). The film deposited using polyethyleneglycol (PEG) as the surfactant consists of nanoparticles with size of ∼25 nm, whereas the film deposited using polyvinylpyrrolidone (PVP) as the surfactant consists of rough rod-like nanostructures (∼50 in diameter and ∼500 nm in length), besides nanoparticles (∼40–180 nm). The SnTe film deposited with PEG is smoother and denser. The formation mechanism of the SnTe films was proposed.
Keywords: SnTe; Film; Chemical bath deposition; Surfactant;

Gallium-doped indium oxide nanoleaves: Structural characterization, growth mechanism and optical properties by Lizhu Liu; Yiqing Chen; Linliang Guo; Taibo Guo; Yunqing Zhu; Yong Su; Chong Jia; Meiqin Wei; Yinfen Cheng (923-927).
► The novel two-dimensional (2-D) Ga-doped In2O3 nanoleaves are synthesized by a simple one-step carbonthermal evaporation method using Cu–Sn alloy as the substrates. ► The nanoleaves protrude outward from the Cu–Sn alloy substrate and are tightly connected to the substrate surface, which would result in a good physical and electrical contact for practical application. ► The room-temperature photoluminescence (PL) measurement of this nanoscaled Ga-doped In2O3 transparent conducting oxide (TCO) detected 2 blue peaks located at 432 nm and 481 nm, respectively, which can be used by Ru-based dye and indicates potential application in dye-sensitized solar cells (DSSCs).The novel two-dimensional (2-D) Ga-doped In2O3 nanoleaves are synthesized by a simple one-step carbonthermal evaporation method using Cu–Sn alloy as the substrates. Two basic parts construct this leaf-like nanostructure: a long central trunk and two tapered nanoribbons in symmetric distribution in relation to the trunk. The Ga–In–O alloy particles are located at or close to the tips of the central trunks and serve as catalysts for the central trunk growth by the self-catalytic vapor–liquid–solid (VLS) mechanism. And the homoepitaxial growth of tapered nanoribbon on the surface of the central trunk can be explained by vapor–solid (VS) mechanism. The room-temperature photoluminescence (PL) measurement of this nanoscaled Ga-doped In2O3 transparent conducting oxide (TCO) detected two blue peaks located at 432 nm and 481 nm, respectively, which can be used by Ru-based dye and indicates potential application in dye-sensitized solar cells (DSSCs). The successful preparation of this novel 2-D Ga-doped In2O3 nanoleaves not only enriches the synthesis of TCO materials, but also provides new blocks in future architecture of functional nano-devices.
Keywords: Transparent conducting oxide; Nanostructured materials; Homoepitaxial growth; Photoluminescence;

Preparation of superhydrophobic surface with a novel sol–gel system by Dong Su; Chengya Huang; You Hu; Qiangwei Jiang; Long Zhang; Yunfeng Zhu (928-934).
This is the illustration of fabrication of by-product and the crosslinked polymethylsiloxane of by-product with PMHS, when PMHS is excessive. The red long chain in the first and second figure stands for hydrolyzate of PMHS, the blue short chain with three branches stands for hydrolyzate of KH550, the green long chain in the third figure stands for PMHS, and the purple parts mean reacting part.Display Omitted► A series of by-products were prepared by polymethylhydrosiloxane (PMHS) reacting with γ-aminopropyltriethoxysilane (KH550). ► When water and ammonia water were added, the by-product could undergo hydrolysis and condensation with excessive PMHS or KH550 to form sol–gel. ► The mass ratio of KH550/PMHS influences surface property of the film produced by spraying the corresponding sol–gel to microscope glass. ► A superhydrophobic film was fabricated by the sol–gel whose mass ratio of KH550/PMHS is 0.25. ► The mechanism of the formation of the by-product and the sol–gel is discussed.Sol–gel method is a simple and cheap way to prepare superhydrophobic coatings or films, however, most of the researches on sol–gel focus on silica or ZnO sol–gel. The present paper proposes a novel sol–gel which is made from hydrolysis and condensation of the by-product of polymethylhydrosiloxane (PMHS) reacting with γ-aminopropyltriethoxysilane (KH550). The mechanism of formation of the by-product and the sol–gel is discussed and the by-product is characterized by FT-IR. The mass ratio of KH550/PMHS of the sol–gel influences the water contact angle (WCA) and water sliding angle (WSA) of the film made of spraying the sol–gel to microscope glass. When the mass ratio of KH550/PMHS of the sol–gel reaches 0.25, WCA of the corresponding film is 157° and WSA of it is less than 1°. The mechanism of formation of the sol–gel is discussed, and the size of the sol–gel is characterized by polarization microscope as well. The morphology of the film made of the sol–gel is analyzed by means of scanning electron microscope (SEM). It was found that the diameter of the particle of the superhydrophobic film is about 40 μm, nevertheless, from the larger magnification picture, the particle is found to be composed of micro-balls whose diameter is about 2 μm, and the micro-ball is composed of nano-sphere whose diameter is less than 200 nm.
Keywords: Superhydrophobic; Sol–gel; Polymethylhydrosiloxane; γ-Aminopropyltriethoxysilane;

► Crystalline to amorphous structure transition of Cr coatings was studied in this paper. ► We focused on the influence of deposition rate on microstructures of Cr coatings. ► We find that Cr coating exhibits dense columnar crystalline structure at 400 W. ► Cr coating exhibits amorphous microstructure with a few nano-crystal grains mixed at 60 W.The influence of deposition rate on crystalline to amorphous microstructure transition of Cr coatings was studied through preparation of Cr coatings deposited onto silicon wafers using magnetron sputtering technique. The microstructure and morphology of Cr coatings were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Results show that Cr coating prepared at 400 W exhibits dense columnar crystalline structure and the crystallite size and crystallization rate are increased expressly in the initial 5 min. When the deposition rate achieved to the maximum, Cr coating shows a case of infinite periodic renucleation where new crystals are assumed to be nucleated periodically on the surfaces of growing crystals and strong persistence of the columnar growth morphology is apparent. However, Cr coating exhibits overall microstructure of amorphous phase mixed with a few nano-crystal grains as the deposition rate decreases to the minimum.
Keywords: Crystalline; Amorphous; Cr coating; Deposition rate;

A new mono-functionalized porphyrin derivative, 5-mono-[4-(2-(4-hydroxy)-phenoxy)ethoxy]-10,15,20-triphenylporphyrin (3) and its Cu(II) (3a), Zn(II) (3b) and Ni(II) (3c) metalloporphyrins were synthesized and characterized. The corresponding 3a, 3b, 3c-TiO2 photocatalysts were then prepared and characterized. The photocatalytic activities of 3a, 3b, 3c-TiO2 were investigated by testing the photodegradation of 4-nitrophenol (4-NP) in aqueous solution under the halogen lamp irradiation. The results indicated that all the 3a, 3b, 3c enhanced the photocatalytic efficiency of bare TiO2, and 3a-TiO2 exhibited the highest photocatalytic activity. The result is considered a combined action of potential match of 3a with TiO2 CB and effective impregnated of 3a onto the surface of TiO2.Display Omitted► A new porphyrin (3) containing a long peripheral substituent with anchoring groups –OH and its Cu(II) (3a), Zn(II) (3b), Ni(II) (3c) metalloporphyrins were synthesized. ► 3a, 3b, 3c-TiO2 photocatalysts were prepared and characterized. ► There exists a weak interaction between TiO2 surface and metalloporphyrin molecules. ► All the 3a, 3b, 3c enhanced the photocatalytic efficiency of bare TiO2 in photodegrading the 4-NP, and 3a-TiO2 exhibited the highest photocatalytic activity.A new mono-functionalized porphyrin derivative, 5-mono-[4-(2-(4-hydroxy)-phenoxy)ethoxy]-10,15,20-triphenylporphyrin (3) and its Cu(II) (3a), Zn(II) (3b) and Ni(II) (3c) metalloporphyrins were synthesized and characterized by using various spectroscopic techniques. The corresponding 3a, 3b, 3c-TiO2 photocatalysts were then prepared and characterized by means of FT-IR and diffused reflectance spectra, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The photocatalytic activities of 3a, 3b, 3c-TiO2 were investigated by testing the photodegradation of 4-nitrophenol (4-NP) in aqueous solution under the halogen lamp irradiation. The results indicated that all the 3a, 3b, 3c enhanced the photocatalytic efficiency of bare TiO2 in photodegrading the 4-NP, and 3a-TiO2 exhibited the highest photocatalytic activity. The result is considered a combined action of potential match of 3a with TiO2 CB and effective impregnated of 3a onto the surface of TiO2.
Keywords: Porphyrins; Metalloporphyrins; Titanium dioxide; Photodegradation; 4-Nitrophenol;

Synthesis of salicylaldehyde Schiff base modified Cu nanocrystals by thermal treatment in liquid paraffin by Yueli Wen; Wei Huang; Bin Wang; Jinchuan Fan; Zhihua Gao; Lihua Yin (946-949).
► Copper nanocrystals are successfully synthesized via thermal treatment in paraffin. ► The cuboid morphology of the nanocopper is controlled by using salicylaldehyde Schiff base as capping agent. ► Copper nanocrystals obtained by this method are not oxidized after exposure to air for one year.Cuboid copper nanocrystals were synthesized by thermal treatment in liquid paraffin without any inert gas protection with salicylaldehyde Schiff base copper (II) (Cu (II)–Salen) complex as precursor. Liquid paraffin was used as solvent and reductant. The obtained copper nanocrystals are morphology-controlled and stable when exposed to air for one year. The nanocrystals were characterized by X-ray diffraction measurements (XRD), UV–visible spectroscopy (UV–vis), transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FT-IR). The results showed that the stable cuboid copper nanocrystals are synthesized by using Salen as capping agents.
Keywords: Nanostructures; Thermal treatment; Microstructure; Electron microscopy;

Adsorption of CO2 on PbO at ambient temperature by Weijun Mu; Di Wu; Jia Liu; Bing Jia; Yan Sun; Wei Su; Yaping Zhou; Li Zhou (950-954).
► The importance of metal oxides for refreshing the atmosphere of an isolated space was indicated. ► It was indicated that the adsorption of CO2 on PbO was considerably enhanced in the presence of water. ► In the monolayer surface dispersion of PbO, both sorption capacity and sorption rate reached the maximal values. ► The wet PbO dispersed on surface of silica gel successfully captured low-concentration CO2 at ambient temperature and pressure.The adsorption of CO2 on metal oxides at ambient temperature received less study largely due to the small adsorption amount. However, the adsorption is of interest in refreshing the atmosphere of isolated spaces. It was shown in the present work that PbO was sensitive to low concentration CO2 in the presence of water. An XPS examination indicated that PbO changed to PbCO3 after the adsorption of CO2; therefore, the adsorption is chemical in nature. In order to enlarge the CO2 capacity, PbO was dispersed on the surface of a silica gel with large surface area (710 m2/g). Both CO2 capacity and adsorption rate indicated that the optimal dispersion manner of PbO is the mono-molecular layer surface coverage. Breakthrough experiments showed that the prepared adsorbent could effectively capture low-concentration CO2 at ambient temperature and pressure yielding a CO2 capacity of 59.1 mg g−1. The saturated adsorbent was regenerated on heating at 380 °C and the CO2 capability was recovered.
Keywords: Adsorption; CO2; PbO; Ambient temperature; Water;

Effect of drying technique on the physicochemical properties of sodium silicate-based mesoporous precipitated silica by Pradip B. Sarawade; Jong-Kil Kim; Askwar Hilonga; Dang Viet Quang; Hee Taik Kim (955-961).
EDS spectra of the sodium silicate-based precipitated mesoporous silica powder.Display Omitted► This paper reports a highly porous silica powders by drying the precipitated wet-gel silica slurry using spray drying technique. ► The spray drying technique effectively removed the water from the wet-gel silica slurry. ► Spray drying is proposed as the best drying technique for the large-scale industrial mass production of highly porous silica powders.The conventional drying (oven drying) method used for the preparation of precipitated mesoporous silica with low surface area (>300 m2/g) and small pore volume is often associated with a high production cost and a time consuming process. Therefore, the main goal of this study was to develop a cost-effective and fast drying process for the production of precipitated mesoporous silica using inexpensive industrial grade sodium silicate and spray drying of the precipitated wet-gel silica slurry. The precipitated wet-gel silica slurry was prepared from an aqueous sodium silicate solution through the drop-wise addition of sulfuric acid. Mesoporous precipitated silica powder was prepared by drying the wet-gel slurry with different drying techniques. The effects of the oven drying (OD), microwave drying (MD), and spray drying (SD) techniques on the physical (oil, water absorption, and tapping density), and textural properties (specific BET surface area, pore volume, pore size, and % porosity) of the precipitated mesoporous silica powder were studied. The dried precipitated mesoporous silica powders were characterized with field-emission scanning electron microscopy; Brunauer, Emmett and Teller and BJH nitrogen gas adsorption/desorption methods; Fourier-transform infrared spectroscopy; thermogravimetric and differential analysis; N2 physisorption isotherm; pore size distribution and particle size analysis. There was a significant effect of drying technique on the textural properties, such as specific surface area, pore size distribution and cumulative pore volume of the mesoporous silica powder. Additionally, the effect of the microwave-drying period on the physicochemical properties of the precipitated mesoporous silica powder was investigated and discussed.
Keywords: Mesoporous silica; Sodium silicate; Cost-effective; Microwave drying; Surface area;

► Time history of impact of an aluminum particle onto steel substrate has been carried out via Ansys software. ► Elastic-perfectly plastic material model is used instead of VOF model. ► Elastic and plastic strains, effective stress, contact pressure and energy densities are predicted. ► The effect of initial impact velocity has a significant effect on splat behavior. ► The mechanical model provides more insights into the dynamics of droplet impact.It is a 2D numerical study which treats the splat and flattening of the droplet during a thermal spraying process. An aluminum particle at a high temperature is impacted on steel substrate. A perfectly elastic–plastic model is used instead of the VOF method which is exclusively used in the literature. For this purpose, the finite element method with Ansys mechanical APDL program is used to solve the governing equations. Displacement, elastic and plastic strains, Von-Mises stress, energy densities, and contact pressure are evaluated during the impact of the particle. Additionally, it is found that the initial impact velocity has a significant effect on splat behavior. This mechanical model gives a promise results that can be improved to help understand the impact and flattening phenomenon.
Keywords: Thermal spray; Ansys; Droplet; Elastic-perfectly plastic; VOF method;

► The N-doped TiO2 nanorods were synthesized by a solvothermal process. ► N-doped TiO2 nanotubes were fabricated by hydrothermally treating the nanorods in NaOH solution. ► The nitrogen content of the N-doped TiO2 nanorods and nanotubes were reached to 36.9 at.% and 25.7 at.%. ► N-doping narrowed the band gaps of the nanorods and nanotubes and introduced indirect band gap to them. ► The nanotubes showed large specific surface area and great degradation efficiency to methyl orange.Nano N-doped TiO2 nanotubes were fabricated by hydrothermally treating N-doped TiO2 nanorods in a 8 M NaOH solution at 110 °C for 20 h. The N-doped TiO2 nanorods were synthesized by a solvothermal process with precursor solution containing titanium sulfate, urea, and dichloroethane. The N-doped TiO2 nanorods and nanotubes were characterized with X-ray diffraction, transmission electron microscopy, and UV–vis spectrophotometry. The nitrogen contents of the N-doped TiO2 nanorods and nanotubes were reached to high values of 36.9 at.% and 25.7 at.%, respectively. The nitrogen doping narrowed the band gap of the N-doped TiO2 nanorods and nanotubes and introduced indirect band gap to the powders, which respectively extended the absorption edge to visible light and infrared region. The nanotubes showed larger specific surface area and greater degradation efficiency to methyl orange than the nanorods.
Keywords: N-doped TiO2; Nano-rods; Nano-tubes; Solvothermal process; Light absorption; Photocatalysis;

► Nanostructured manganese (Mn)-containing thin Ti oxide film (Mn2O3) on pure titanium was produced by hydrothermal treatment. ► Mn-incorporated Ti oxide layer released Mn ions from the surface into the solution. ► Mn2O3 coating decreased cellular attachment, spreading, proliferation, alkaline phosphatase activity, and osteoblast phenotype gene expression compared with bare titanium surface. ► This is the first demonstration that Mn ion in Ti oxide layer does not exert any beneficial effects on osteoblastic cell response, it rather impaired cell function.This study investigated the surface characteristics and in vitro biocompatibility of a titanium (Ti) oxide layer incorporating the manganese ions (Mn) obtained by hydrothermal treatment with the expectation of utilizing potent integrin–ligand binding enhancement effect of Mn for future applications as an endosseous implant surface. The surface characteristics were evaluated by scanning electron microscopy, thin-film X-ray diffractometry, X-ray photoelectron spectroscopy, optical profilometry and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The in vitro biocompatibility of the Mn-containing Ti oxide surface was evaluated in comparison with untreated bare Ti using a mouse calvaria-derived osteoblastic cell line (MC3T3-E1). The hydrothermal treatment produced a nanostructured Mn-incorporated Ti oxide layer approximately 0.6 μm thick. ICP-AES analysis demonstrated that the Mn ions were released from the hydrothermally treated surface into the solution. Mn incorporation notably decreased cellular attachment, spreading, proliferation, alkaline phosphatase activity, and osteoblast phenotype gene expression compared with the bare Ti surface (p   <  0.05). The results indicate that the Mn-incorporation into the surface Ti oxide layer has no evident beneficial effects on osteoblastic cell function, but instead, actually impaired cell behavior.
Keywords: Titanium oxide; Manganese ion; Biocompatibility; Osteoblast; Surface modification;