Photocatalytic mechanisms of modified titania under visible light

Heterogeneous photocatalysis with titania under visible light has increasingly been a focus for research. Metal or non-metal doping, surface sensitization, semiconductor coupling, precious metal deposition and increasing crystal defects have been used to enhance the photocatalytic activity of titania under visible light. Based on the research results of different modification methods in recent years, some mechanisms from the excitation, bulk diffusion and surface transfer of photoinduced charge carriers, such as band gap modification, changing the excitation path, promoting the separation of photogenerated charge carrier, improving the surface adsorption and reaction, and synergistic effects, for photocatalysis under visible light are discussed and the development trend in this field is predicted.