Titanium oxide based photocatalytic materials development and their role of in the air pollutants degradation: Overview and forecast

Due to the anthropogenic pollution, especially the environmental crisis caused by air pollutants, the development of air pollutant degradation photocatalyst has become one of the major directions to the crisis relief. Among them, titania (titanium dioxide, TiO2) family materials were extensively studied in the past two decades due to their strong activity in the photocatalytic reactions. However, TiO2 had a drawback of large bandgap which limited its applications, several modification techniques were hence developed to enhance its catalytic activity and light sensitivity. In recent years, other metal oxide based materials have been developed as replacements for TiO2 photocatalysts. In this review, background information and developments from pure TiO2 to chemically modified TiO2-based materials as photocatalysts were discussed in detail, which covered their basic properties and their role in the air pollutant removal. It also proposes to solve the shortcomings of TiO2 by developing other metal oxide-based materials and predict the future development of TiO2 materials in future environmental applications.