Stable V-MCM-41 mesoporous materials have been synthesized by hydrothermal method, using hexadecyl-trimethyl-ammonium bromide as template, and industrial Na2o (3.3-3.5)SiO2 as the source of much cheaper silica instead of conventional expensive organic precursors. Several modern techniques like XRD, N2 adsorption, FT-IR, UV-vis and SEM have been utilized to characterize the framework structure and texture of the samples. The results of N2 adsorption and X-ray diffraction showed that the synthesized samples had a high ordered hexagonal structure, good hydrothermal stability and thermal stability. The selective oxidation of styrene using hydrogen peroxide as oxidant over V-MCM-41 samples showed a good catalytic performance of partial oxidation, the phenylacetic acid was the principal product (the selectivity value was 49.4%). Even after a thermal treatment at 900 0C in air for 12 h or a hydrothermal treatment in boiling water for 8 days, each of the two resultant materials could retain the ordered channels and a high BET surface area. UV-vis spectra provided strong evidences that most of vanadium ions were incorporated into the framework of siliceous MCM-41 sample.

For the selective hydrogenation of acetylene, the novel Pd/ -Al2O3 catalysts prepared by plasma method were investigated. The inuence of the preparation method, content of Pd active component, catalyst promoter and reaction temperature has been investigated. It was found that the conversion and selectivity of the catalysts prepared by glow discharge plasma were superior to those obtained from the conventional catalysts. The acetylene conversion of 100% and the selectivity of 71.3% in C2H4 were obtained at 50℃ over the plasma-prepared sample (0.15 wt.% Pd), while the plasma-prepared catalyst was stable during the long-time test for more than 20 h. 2003 Elsevier B.V. All rights reserved.

Novel titania supports have been designed and elaborated with the hydrolysis precipitation method, by adjusting and controlling of the main preparation parameters, such as pH value, adding rate of tetrabutyl titanate Ti(OBu)4, and calcining temperature of precursor during support preparation. The new titania supported Pd catalysts were prepared and investigated for selective hydrogenation of acetylene to ethylene. The catalyst samples have been characterized by temperature programmed reduction (TPR), XRD and BET tech- niques. The experimental results indicated that with MgO modication, the improved catalyst (0.5%Pd–MgO/TiO2) showed better performance of high and stable activity. 2006 Elsevier B.V. All rights reserved.

The effect of preparation method on MnOx–CeO2 mixed oxide catalysts for methane combustion at low temperature was investigated by means of BET, XRD, XPS, H2-TPR techniques and methane oxidation reaction. The catalysts were prepared by the conventional coprecipitation, plasma and modied coprecipitation methods, respectively. It was found that the catalyst prepared by modied coprecipitation was the most active, over which methane conversion reached 90% at a temperature as low as 390 °C. The XRD results showed the preparation methods had no eect on the solid solution structure of MnOx–CeO2 catalysts. More Mn4+ and richer lattice oxygen were found on the surface of the modied coprecipitation prepared catalyst with the help of XPS analysis, and its reduction and BET surface area were remarkably promoted. These factors could be responsible for its higher activity for methane combustion at low temperature.