Study On Mechanism Of Multiphase Photocatalytic Activity Of Thin TiO₂ Photoelectrode With Electrochemistry Impedance Spectroscopy

The Electrochemistry Impedance Spectroscopy (EIS) of the thin TiO2 photoelectrode prepared by sol-gel processing in Ammonia system was measured and analyzed by a PARSTAT2273. The influence of light and bias on the photoelectro-catalytic process was discussed with the EIS change. The results of experiments of ammonia degradation were identical to the former conclusions and the photocatalytic efficiency is the highest with bias potential 0.1V. The Equivalent Circuit Model R(C(R(RQ))) was the better one. The parameters of the width of space charge layer, flat band potential, and density of donors of the semiconductor were calculated.Photocatalytic reduction of molecular nitrogen to ammonia on TiO2 was also studied in this paper. When pH was 3, the effect of different reaction condition, such as reaction time, solution concentration, applied bias and pumping into different kinds of gas, on increasing of ammonia concentration was compared. The results showed that the ammonia concentration increased most and the efficiency was 6.7% in the condition of applied bias 0.1V and pumping into air after 60 minutes.