Cu/WO3-NiO上光促表面催化二氧化碳与水合成甲醇反应的规律

 采用溶胶－凝胶法制备了n－p复合半导体材料0．75％Cu／WO3－1．5％NiO，用X射线衍射、透射电镜、红外光谱、紫外－可见光漫反射和程序升温脱附等技术对材料结构、吸光性能和化学吸附性能进行了表征，研究了该材料对CO2与H2O合成CH3OH的光促表面催化反应(PSSR）规律．结果表明：所制备的材料明显有利于促进目的反应，室温条件下就有CH3OH生成，选择性超过90％，升高反应温度可提高CH3OH产量，且选择性仍高于88％．根据实验结果，得出CO2在材料表面的卧式吸附态为CH3OH的前驱物，并对PSSR机理进行了讨论．

Photo-Stimulated Surface Reaction for Synthesis of Methanol from Carbon Dioxide and Water on Cu/WO3-NiO

Solid material of metal loaded n-p coupled semiconductors 0.75%Cu/WO_3-1.5%NiO, prepared by sol-gel method, was introduced into phto-stimulated surface reaction (PSSR) process to synthesize CH_3OH from CO_2 and H_2O. XRD,TEM,IR,UV-Vis and TPD-MS experiments were used to characterize the surface structure, photon absorbing and chemisorbing ability of the material. It was shown that the material obtained is of particles with average diameter of 27.1 nm, and possesses several types of active adsorption sites on its surface. After adsorption, according to IR and TPD-MS results, H_2O exists as both dissociated (OH group) and molecular states, while CO_2 chemisorption was proved to result in the formation of several surface species including its monodentate carbonate, linear, shearing and horizontal states, among which horizontal state possesses the activity of thermo-decomposing to produce CO. The material prepared can obviously enhance the destination PSSR, during which CH_3OH and CO can be secured at normal temperature with a high selectivity (90.5%) for CH_3OH. Increasing temperature can raise the production of CH_3OH with the selectivity greater than 88%. According to the results of TPD-MS and PSSR at different temperatures, the surface precursor of CH_3OH was specified to be horizontal state of CO_2, based on which PSSR process was discussed and a three-step mechanism was presented: (1) chemisorption of reactants on material surface, (2) photo-activation of the material, and then the re-distribution of current carriers, (3) further reaction of surface species to produce CH_3OH.