Effects of H_2O_2 on TiO_2 photocatalysis under visible light irradiation

The effects of H2O2 on TiO2 visible-light photocatalytic performance were studied,using anatase,rutile and mixing crystalline TiO2 as photocatalysts.The results indicate that the absorption of H2O2 on TiO2 surface to form active species extends the light absorption range of TiO2 into the visible light region.Fluorescence spectrum analysis indicates that the ·OH radical free from rutile TiO2 surface can be constantly produced under visible light irradiation with addition of H2O2.The photocatalytic tests indicate that phenol can be visible-light photocatalytic degraded with the addition of H2O2 by any one of the three photocatalysts,and the rutile form exhibits the best photocatalytic activity,its degradation ratio can be 80% after 120 min reaction.In the process of TiO2 visible-light photocatalysis,hydrogen peroxide is generated by anatase TiO2 from a series of complex reaction,and the generated hydrogen peroxide is only an intermediate,which is responsible for the degradation of organic pollutants under visible light irradiation.