Visible Light Responsive Photocatalytic Degradation of 4-Chlorophenol on Neat TiO2 by Surface-Complex-Mediated Path

The visible light responsive photocatalytic degradation of 4-chlorophenol was investigated in aqueous suspension of pure TiO2 under visible light by a surface-complex-mediated path. The addition of tert-butyl alcohol, a common OH radical scavenger, did not affect the visible activity of 4-chlorophenol, which indicates that OH radicals are not responsible for the degradation. UV-Visible result indicated that the surface complexation between phenolic compounds and TiO2 was formed, which was responsible for the visible light activity. The activity decreased dramatically after Pt deposition. The photocatalytic activity increased with increasing the S-BET of the catalyst. The crystal proportion of catalyst strongly influence the photocatalytic activity. The possible mechanism was investigated.