CO_2和C_2H_4光催化合成丙烯酸的Cu/ZnO-TiO_2催化剂  

Study on Cu/ZnO-TiO_2 Catalyst for Photo Stimulated Synthesis of Crylic Acid from CO_2 and C_2H_4

作　　者：赵春[1] 钟顺和[1] 

机构地区：[1]天津大学化工学院,天津300072

出　　处：《Chinese Journal of Chemical Physics》2005年第2期273-278,共6页化学物理学报（英文）

基　　金：ProjectsupportedbytheNationalKeyResearchofChina(2001CCA03600)

摘　　要：采用溶胶凝胶法制备了金属负载的复合型固体材料Cu/ZnO-TiO2,并用X射线衍射、透射电子显微术、BET比表面测试、红外吸收光谱、紫外-可见漫反射光谱以及光催化反应等实验技术对固体材料的表面结构、光响应性能、化学吸附性能以及光反应性能进行了表征和评价.实验结果表明,制得的固体材料粒径约为10 nm,晶体结构以锐钛矿型TiO2为主; ZnO和TiO2复合后部分地形成了Zn - O - Ti键联,提高了对250～400 nm光的吸收强度;金属Cu的负载扩展了材料在可见光范围的吸收,且使其紫外吸收限发生蓝移;反应物在固体材料表面的吸附态是影响光反应结果的主要因素; CO2卧式吸附态和C2H4非解离双点吸附态是光合成丙烯酸的有效吸附态, 100℃以下合成丙烯酸的选择性大于87%.The metallic Cu modified n-p coupled semiconductor Cu/ZnO-TiO2 was prepared by the sol-gel method, and its surface structure, absorptivity of ultraviolet light, chemisorption properties and photocatalytic behaviors were investigated by techniques of X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), BET surface area ( BET), Infrared absorption spectra (IR), UV-visible diffused reflectance spectra (UV-vis) and photo stimulated surface catalytic reaction. The results show that the main crystal structure of the catalyst is anatase TiO2 with the particle size about 10 rim. The Zn-O-Ti bond is formed and the absorption intensity in the wavelength region of 250 ∼ 400 nm is enhanced through the coupling of ZnO and TiO2, while the absorption region is expanded to visible light with the UV absorbance limit shifting to the shorter wavelength region after Cu supported on the coupled semiconductor ZnO-TiO2. The adsorption states of reactants are important factors influencing the results of photocatalytic reaction, while the bridge adsorption state of CO2 formed on Cu and Lewis acid sites Ti4+ and undissociated of C2H4 formed on Cu and Lewis base sites bridge-O are the effective intermediates to synthesize the crylic acid with the selectivity over 87% under the temperature of 100° C.

关 键 词：光催化 CO2 C2H4 丙烯酸 复合型固体材料Cu/ZnO—TiO2 

分 类 号：TQ225[化学工程—有机化工]