Photocatalytic activity and interfacial carrier transfer of Ag-TiO2 nanoparticle films

Many studies have been devoted to the improvement of photoactivity of TiO2 by depositing noble metals. The electrodes of Ag-TiO2 with different Ag content are prepared by a modified sol-gel method. The photochemical properties of Ag-TiO2 with different Ag content are characterized by surface photovoltage spectroscopy (SPS). The results show that the SPS intensity decreased with increasing Ag contents. This demonstrates that the doping Ag plays the roles trapping photoinduced electrons, which inhibiting the recombination of photoinduced electrons and holes. The photoelectrochemical properties of Ag-TiO2 electrodes with different Ag content are performed by electrochemical impedance spectroscopy (EIS) under high-pressure mercury lamp (160 W) illuminating, and photocatalytic degradation of RhB are studied at the same time. The experimental results indicate that the process of charge transfer is a controlled-step of photocatalytic reaction. The SPS intensity and the electrical impedance values of EIS equivalent circuits are contrary to photocatalytic degradation ratio of RhB.