Recent progress in enhancing photocatalytic efficiency of TiO 2 -based materials

Titanium dioxide (TiO2) has been proved to be a leading semiconductor material to removal of environmental pollutants. However, it suffers from low photocatalytic efficiency under visible-light irradiation and narrow light response range because of its intrinsic large band gap. One of the most significant scientific and commercial progresses to date has been the development of visible light active TiO2 by incorporation of additional components in the TiO2 structure. In this review, a variety of strategies to improve the photocatalytic efficiency and shift the photocatalysis to visible light range are discussed. The materials are covered in the review including TiO2/SiO2, TiO2/carbon nanotube, TiO2-graphene/grapheme oxide, non-metal and/or metal doped TiO2. Emphasis is given to highlight current techniques and recent progress in enhancing photocatalytic efficiency of TiO2-based materials, which drives the rising of some key strategies involved in the ongoing challenges and potential new directions of TiO2 photocatalysts.