TiO2纳米粒子的表面光电压与光催化活性的关系

为了研究不同改性催化剂的SPS信号强度变化的原因及其与光催化活性之间的关系.文中制备了三种光催化剂:表面沉积贵金属银的Ag-TiO2纳米粒子、不同pH条件下水热法制备的TiO2纳米粒子、过渡金属铁离子掺杂的Fe-TiO2纳米粒子,并利用SPS技术分析了所制备催化剂光生电子-空穴的分离效率.实验结果表明:对于Ag-TiO2体系,表面光电压信号越弱,光催化活性越高;而对于水热法制备的TiO2体系和Fe-TiO2体系,则是表面光电压信号越强,光催化活性越高.所制备光催化剂的SPS信号强度变化与其光生载流子的分离及复合机制必然有着联系,因此可利用SPS分析技术快速评价催化剂的活性.

Relationship between SPV and photocatalytic activity of modified TiO2 nanoparticles prepared by different methods

In order to investigate the reasons of SPS intensity variation with different modified photocatalysts and the relationship between the photocatalytic activity and the intensity of SPS spectra, three different photocatalysts were prepared: Ag-TiO2 nanoparticles with the deposited noble metal Ag on the surface of TiO2, TiO2 nanoparticles prepared by hydrothermal method in different mediums and Fe-TiO2 nanoparticles with overdoped Fe3+ in TiO2. As-prepared catalysts were mainly tested by SPS. Experimental results indicate that for Ag-TiO2 system, the lower is the intensity of SPS response, the higher is the photocatalytic activity; and for TiO2 systems synthesized by hydrothermal method and Fe-TiO2system, the stronger is the intensity of SPS respons, the higher is the photocatalytic activity. This fact is closely associated with the mechanism of photoinduced carriers separation and recombination. So the activity of photocatalysts may be quickly estimated by SPS measurements.