纳米薄膜光催化剂的制备与表面态研究

Preparation and Study of the Surface States on Nano Particle Photocatalyst Films

利用溶胶-凝胶提拉成膜法制备了TiO2,SnO2,Ag/SnO2,Ag/SnO2/TiO2纳米薄膜半导体催化剂.采用粉末电导法初步研究了纳米半导体薄膜催化剂的表面结构,测定了表面态能级相对于半导体导带边的位置.实验表明:四种催化剂在不同的表面能级位置都存在表面态:TiO2具有两类表面态,其能量分别为0.75eV和0.58eV.Ag/SnO2/TiO2由于Ag的担载,出现更负的表面态能级(0.33eV).这将会显著提高导带电子密度,加速光催化反应速率.

Nanometer TiO2,SnO2,Ag/SnO2,Ag/SnO2/TiO2 films were prepared by the method of solgel. The surface structures, energy levels and their distribution of the surface states were measured by the powder conductivity. The experimental results show that the different energy levels exist at the surface of the four samples. Two types of surface states exist at the surface of TiO2 , the energy levels are 0.75 eV and 0.58 eV respectively. Because of the Ag loaded, the energy level of Ag/SnO2/TiO2 changes towards more negative (0.33 eV ), which increases the electron concentration in the conduction band and accelerates the reaction speed of photocatalysis.