TiO2/SnO2复合光催化剂的耦合效应

采用改进的sol gel技术制备TiO2/SnO2耦合型半导体光催化剂,利用XRD、气相色谱 仪、粒度仪和表面光电压装置等研究了耦合型半导体光催化机理和光催化效率的影响因素, 并通过降解甲醛探讨其在空气污染治理中的作用.实验结果表明,添加20 ％(mol) SnO2的复 合半导体光催化剂,其光催化效率比纯TiO2高一倍以上.据实验结果和粒子紧密堆积原理,提 出强耦合效应和弱耦合效应的光催化反应模型,并用此模型较好地解释了TiO2/SnO2复合型半 导体光催化剂的光催化效率随SnO2含量变化规律.

Coupling Effect for TiO2/SnO2 Compound Semiconductor Photocatalyst

The photocatalyst of TiO2/SnO2 compound semiconductor was prepared by improved sol gel method.The coupling mechanism and the factors affecting photoc atalytic efficiency were studied by using XRD,gas chromatography,granularity equ ipment and surface photovoltage spectroscopy.TiO2/SnO2 catalysts were employed f or photocatalytic degradation of formaldehyde.The experimental results showed th at phtocatalytic efficiency of TiO2 catalyst was greatly enhanced by adding SnO2 into TiO2,and the optimum content of SnO2 was about 20 ％(mol).According to the particle close packing rule and experimental result,the strong and weak couplin g effect models for TiO2/SnO2 compound semiconductor were proposed.The coupling effect was derived from the close packing structure of the photocatalyst particl es.The critical bourn between enhanced and weaken effect depends on whether the close packing structure is three dimensional or not.The photocatalyst doped wit h SnO2 less than 20 ％(mol) presented a three dimensional structure,which impro ved the activity of the photocatalyst due to effective separation of the photoge nerated carriers.The opposite situation was occurred when content of SnO2 was mo re than 20 ％(mol).