负载金属对WO_3-TiO_2光催化剂结构与催化性能的影响  

Effects of Loaded Metal on Structure and Photocatalytic Performance of Photocatalyst for Synthesis of MAA from Propylene with Carbon Dioxide

作　　者：梅长松[1] 钟顺和[1] 

机构地区：[1]天津大学化工学院,天津300072

出　　处：《化学学报》2005年第19期1789-1794,共6页Acta Chimica Sinica

基　　金：国家重大基础研究前期研究(No.2001CCAO3600)资助项目

摘　　要：用溶胶-凝胶和浸渍-还原相结合的方法制得M/WO_3-TiO_2(M=Pd,Cu,Ni,Ag)光催化剂.利用X射线衍射(XRD)、程序升温还原(TPR)、红外(IR)、程序升温脱附(TPD)、紫外-可见漫反射光谱(UV-Vis-DRS)和光反应器等技术研究了复合半导体负载金属的物相结构、光吸收性能和光催化反应性能.结果表明:金属负载在复合半导体上延迟了TiO_2由锐钛矿向金红石相转化,增强W与载体TiO_2的相互作用,使TiO_2光吸收限发生蓝移,对可见光部分的吸收明显增加;固体材料吸光性能强弱顺序Pd/WO_3-TiO_2>Cu/WO_3-TiO_2>Ag/WO_3-TiO_2>Ni/WO_3-TiO_2;金属Pd对CO2吸附能力过强,卧式吸附态脱附温度高,光催化效率不高;金属Cu对CO_2吸附能力适中,CO_2与C_3H_6脱附温度较接近,实现了“光-表面-热”协同作用,光量子效率最高,达到19.7%.M/WO3-TiO2 （M=Pd, Cu, Ni, Ag） photocatalysts were prepared by sol-gel and impregnation-reaction method. The surface structure, photo absorption performance and photo catalytic performance of M/WO3-TiO2 catalysts were characterized by XRD, XPS, TPR, IR, TPD, UV-Vis-DRS and photoreactor techniques. The experiment results showed that the metal supported on coupled semiconductor WO3-TiO2 restrained the transformation from anatase TiO2 to rutile TiO2. The blue shift of photo absorption edge and increase of the photo absorption capacity to visible light were observed clearly after the addition of metal to WO3-TiO2. The photo absorption performance was decreased in the order of Pd/WO3-TiO2, Cu/WO3-TiO2, Ag/WO3-TiO2 and Ni/WO3-TiO2. It can be concluded from the analysis results that the adsorption capacity of CO2 on Pd/WO3-TiO2 was much stronger than others. Its desorption temperature of horizontal adsorption state was increased, so its photo quantum efficiency became lower. Photo quantum efficiency of Cu/WO3- TiO2 was the highest, on which desorption temperature of CO2 was approximate to C3H6. Photo quantum efficiency of the reaction reached 19.7% and the selectivity to MAA was over 95% on Cu/WO3-TiO2 catalyst under proper reaction conditions： vs （space velocity） 200 h-1, pressure 0.1 MPa, temperature 110℃ and UV light intensity 0.65 mW·cm^-2. Loaded metallic Cu on coupled semiconductor WO3-TiO2 realized photosurface-thermal synergistic effects and improved photo quantum efficiency.

关 键 词：复合半导体 光量子效率 二氧化碳 丙烯 甲基丙烯酸 负载金属 催化剂结构 催化性能 程序升温还原 光吸收性能 

分 类 号：O643.36[理学—物理化学] TQ342.86[理学—化学]