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以硫脲为S的源物质,以钛酸丁酯为TiO2的前驱体,采用溶胶-凝胶法制备S-TiO2光催化剂。利用XRD,XPS和FTIR等技术分析S掺杂对TiO2晶格结构的影响,并探讨元素S在TiO2晶格中的化学状态以及所形成的化学键的类型。结果表明:掺杂的S以S4+进入TiO2晶格中取代部分Ti4+,形成Ti1-xSxO2催化剂;S4+在TiO2的价带上形成1个电子占据能级,价带上的电子占据能级的价带顶位主要由S3p态构成,同时S3p也有助于形成1个由Ti3d和O2p态构成的导带,S3p态与价带的交叉使价带变宽,导致能带变窄,从而改善TiO2的光谱响应,使吸收边缘扩展到可见光的区域。对亚甲基蓝的光降解实验结果证实硫掺杂明显提高了光催化活性。
S-TiO2 photocatalyst was prepared by sol-gel method using thiourea as the source material of S and butyl titanate as the precursor of TiO2. The effects of S doping on the crystal structure of TiO2 were analyzed by XRD, XPS and FTIR techniques. The chemical state of the element S in the TiO2 crystal lattice and the types of chemical bonds formed were also discussed. The results show that the doped S forms a Ti1-xSxO2 catalyst by substituting S4 + into the TiO2 lattice and forming an electron occupying level on the valence band of TiO2, and the valence band occupying an energy level in the valence band The top sites are mainly composed of S3p states, and S3p also contributes to the formation of one conduction band composed of Ti3d and O2p states. The crossover of the S3p states with the valence band broadens the valence band, resulting in narrowing of the energy band and improving the spectrum of TiO2 In response, the absorbing edge extends to visible light. The results of photodegradation of methylene blue confirmed that sulfur doping significantly enhanced the photocatalytic activity.