Cu/ZnO-TiO_2复合半导体光催化材料的制备与表征  

Preparation and Characterization of Cu/ZnO-TiO_2 Coupled-Semiconductor Photocatalyst

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：《无机化学学报》2004年第9期1131-1136,共6页Chinese Journal of Inorganic Chemistry

基　　金：国家重大基础理论研究前期研究专项(No.2001CCA03600)。

摘　　要：O引言ZnO和TiO2两种宽禁带半导体由于在光催化方面显示出的优异性能而倍受关注[1].但是单一半导体在反应中存在易发生光腐蚀、光子利用率低以及氧化还原电势无法调变等缺陷[2],使其应用受到限制.基于此种原因,目前的研究多以ZnO或TiO2为基础,通过金属离子掺杂、金属负载以及半导体复合等手段进行修饰以优化其性能[3],但是对于ZnO和TiO2复合体系的研究较少,且制备方法集中于机械混合法[4,5].ZnO和TiO2具有相近的禁带宽度(Eg=3.2 eV)[2]和交错的能带位置[6],若将二者在分子水平上混合并加入金属进行调变,其结果及性质的变化将对光催化材料的设计及制备等研究具有重要意义.本文采用溶胶凝胶法制备了金属负载的复合型半导体材料Cu/ZnO-TiO2,并着重研究了这种材料的晶体结构、化学组成以及光响应性能.The metallic Cu modified n-p coupled semiconductors Cu/ZnO-TiO2 were prepared by sol-gel method, and their crystal structure, surface composition and absorptivity of UV light were investigated by techniques of DTA-TG, XRD, TEM, BET, TPR, IR and UV-Vis. The results show that the main crystal structure of the coupled-semiconductors is anatase TiO2 with the particle size in the range of 10similar to16 nm and BET surface area above 80 m(2).g(-1). In the process of Sol-gel the probability to form ZnO is reduced because of the dilution of Zn2+ with Ti(OC4H9)(4). But through the molecular-level contact with TiO2 Zn2+ cations take the places of the O-tetrahedral and O-octahedral centers to partly form Zn2TiO4, and the coupling effects decrease the reflectivity of semiconductors in the wavelength region of 250similar to400 nm. A photo-exciting mechanism of the semiconductors embedded with metallic Cu was proposed. The Fermi energy of metallic Cu is in the band gap of ZnO and TiO2, so the addition of metallic Cu offers new energy bands to give and receive the photoelectrons, thus expanding the absorption region of the semiconductors to visible light.

关 键 词：复合半导体材料 光催化剂 制备 溶胶凝胶法 晶体结构 化学组成 光响应性能 

分 类 号：O643.36[理学—物理化学] TN304[理学—化学]