Advanced Materials Research Vols. 875-877

Abstract: Selective catalytic reduction (SCR) is a well-proven method to reduce NO emission. However, to choose the right catalyst that provides a surface for reaction between NO and ammonia at low temperatures is a challenging task for a catalysts developers. In an earlier study, we prepared V₂O₅-CeO₂-SiO₂ catalyst with increasing V₂O₅ content by sol-gel route and found that the catalytic activity improved with increasing the V₂O₅ loading up to 0.5%. The catalytic activity, however, dropped when V₂O₅ loading was about 1% and increased back when the loading of V₂O₅ was about 5%. In this study, we looked into the microstructural relationship to explain these findings. The microstructures of the catalysts before and after exposure to NO gas revealed that the catalysts with 0.2% and 0.5% V₂O₅ were more porous after the reduction process possibly due to improved breakdown of (NH₄)HCO₃ to NH₃ by the possible interaction with the V₂O₅ and CeO₂-containing catalysts which consequently resulted in a more efficient NO reduction to N₂ and H₂O at low temperature. The microstructure of the catalyst with 1% V₂O₅ content to 5%, improved back the efficiency although clogging by CeVO₄ phase still possible due to its presence based on XRD. The well-ordered micropores before exposure to NO and the more efficient breakdown of (NH₄)HCO₃ could have contributed to increase back the catalytic activity at low temperature.

Abstract: Ti,Cr)N films were fabricated on the well-polished high-speed-steel substrate under various deposition conditions by arc ion plating. X-ray diffraction was employed to characterize the phase and microstructure of the films, and the preferred orientation of the crystalline plane was discussed in terms of negative bias and nitrogen flow, respectively. The morphology of the films was investigated using scanning electron microscopy. The size and density of macro-particles were compared for different bias and nitrogen flow. The mechanical properties of the films were investigated. The hardness and elastic module were tested by the XP nanoindenter. The results show that the size as well as the number of the macro-particles decreases with increasing negative bias, presenting a smoother surface. The films have preferred (111) plane at low biases but (200) plane at high ones. The hardness and elastic modulus of (Ti,Cr)N films increases with increasing negative bias. Larger hardness can be achieved by increasing nitrogen flow. It is found that the mechanical properties, such as hardness and elastic module of (Ti, Cr)N films are better than those of TiN films, according to the comparison of the experimental results. It indicates that the mechanical properties of TiN can be enhanced by doping Cr. The mechanism is also discussed and analysed by taking deposition parameters into account.

Abstract: Influence of argon flow on the optical properties of titanium oxide films, which were fabricated on well-polished K9 glass substrate through r.f. magnetron sputtering, has been investigated. X-ray diffraction (XRD) was employed to analyse the microstructure. Surface morphology was observed by atomic force microscopy (AFM). Transmittance of the films was measured within the visible range by UV-3600 spectrometer. The optical constants, such as thickness, refractive index and extinction coefficient, were measured using an ellipsometer. The experimental results and the effects of argon flow on optical constants of the TiO₂ films have been discussed and analysed.

Abstract: Diethyl dithiocarbamate [Cd (S₂CN Et₂)₂] complex is used to deposit the cadmium sulphide thin film at much lower temperature by Aerosol Assisted Chemical Vapour deposition (AACVD) and same precursor is used to synthesize the nanocrystals in Oleylamine at elevated temperature. Thermogravimetric analysis shows that precursor [Cd (S₂CN Et₂)₂] decomposes in the single stage, losing 62% of total weight. Deposition of thin films at 300 ^°C and 400 ^°C showed the growth of CdS clusters which were made of granular crystallites. These results are confirmed by SEM analysis. Thermolysis of the precursor in oleylamine at 240 ^°C gave the nanoparticles most of them are monodispersed spherical shape, few having mono and dipod structures. TEM images confirm the structures. XRD results show the thin films and nanoparticles have hexagonal phase of CdS.

Abstract: A simple, two-step fabrication technique was presented to prepare the Ag/ZnO hybrid nanostructures using silver nitrate and zinc nitrate. Silver particles were synthesized by chemical reduction method and the ZnO layer was coated on the surface of silver using wet chemical method. The microstructure, the composition and the optical properties of the obtained materials were further characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence (FL) spectroscopy. The results showed that the silver and zinc oxide composite had been successful prepared. The intensity of fluorescence showed an enhancement of R6G (dye) indicate that ZnO shell had an improvement on the silver metal enhance fluorescence.

Abstract: The phenyl trimethyl ammonium bromide (PTMAB) and Keggin polyhydroxyl aluminum cations (Al13) as pillared agent and montmorillonite as the carrier, organic - inorganic pillared montmorillonite was prepared through sol-gel method to remove sulfur in model gasoline. The results showed when adsorption time was 1.5 h and reaction temperature was 40 °C, the maximum adsorption capacity of PTMAB-Al-MMT was 5.32 mg/g. The modified materials were characterized by X-ray diffraction, Nitrogen adsorption-desorption and NMR techniques to investigate the material structure and the adsorption mechanism. After the intercalation of PTMAB and Keggin Al13 in MMT, the interlayer d-spacing, specific surface and pore volume area increased to 1.10 nm, 41.23 m2 /g and 0.16cm3/g, respectively.

Abstract: Bioethanol is widely used as renewable resource due to its safe to produce and environmentally friendly. However, knowledge on ethanol production from pineapple peel juice (Pattawia spp) is far from sufficient. In this work, pineapple peel juice (initial pH at 5) was fermented at various yeast contents (1, 3 and 5% by wt.) and fermentation times (3, 5 and 7 days) in order to investigate ethanol production characteristics. Yeast, Sacchromyces cerevisiae was grown on pineapple peel juice. The squeezed juice contained 11% of total sugar and 5% of reducing sugar. The results indicated that the optimum ethanol production was yeast contents of 5% by wt. and fermentation times of 5 days which gave the ethanol production of 9.08g/l. The ethanol at a higher yeast content also had a higher ethanol concentration.

Abstract: Metallic copper ultra-thin layers were synthesized by modified PE CVD method from low-sized volatile metal complexes consisting of small (2- to 5atomic) ligand molecules. To characterize the deposited copper layers the X-ray photoelectron (XPS), infrared (FTIR) and UV-vis spectroscopy, SEM, XRD analyses were used. The layers were found to be nanocrystalline and have a nanoscale grain structure with parameters depending on the experimental conditions. It was revealed that plasma activation decreases mean size of copper grains and increases its stability on the air. The microstructure of the layers was examined by scanning electron microscopy (SEM) and diffraction of synchrotron radiation (DSR) methods, and chemical composition with a predominant content of copper in the metallic state Cu0.

Abstract: Ag/ZnO nanocomposite photocatalysts with high photocatalytic performance were successfully synthesized via a facile sol-gel method. The prepared Ag/ZnO products were characterized by XRD, SEM, EDS, FT-IR, BET surface area, TG and DSC. Photodegradation experiments of the samples were carried out by choosing Methylene Blue (MB) as a model target under UV irradiation with homemade photocatalytic apparatus. Among these products, when the molar ratio of Ag to ZnO was fixed at 0.07 and the calcination temperature was around 450 °C, the obtained samples exhibited the highest photocatalytic activity.

Abstract: A series of micron-sized elastic microspheres were optimally prepared through inverse suspension polymerization of acrylamide (AM) and N, N’-methylene bisacrylamide (MBA) in oil phase when [Span80 & Tween80] and ammonium persulfate (APS) were used to be dispersion stabilizer and initiator, respectively. Their profile control and flooding performance in mid-high permeability sand pack models were characterized in laboratory. The results show that the conversion rate is high, and the coagulum is low when the mass ratio of Span80 to Tween80 is 3:1. The particle size of the elastic microspheres can be controlled by varying the amount of dispersion stabilizer. The micron-sized elastic microspheres can plug sand pack effectively and selectively. The ultimate plugging rate is more than 90% and the ability of profile improvement is up to 70%. The results indicate that the micron-sized elastic microspheres have better profile control and oil flooding performance in the heterogeneous mid-high permeability reservoirs.