Factors that enhance the efficiency of TiO₂ based heterogeneous photocatalyst for its application in waste water treatment containing organic dye

TiO₂ is one of the well known photocatalyst in the field waste water treatment technology. Besides the unique properties of TiO₂ such as its inert nature and low cost, wide bandgap of TiO₂ limits the photocatalytic property under the illumination of UV radiation. The photocatalytic efficiency of TiO₂ under natural visible light can only be achieved by forming heterojunction with other non-TiO₂ compound. In this review article, different factors that can enhance the photocatalytic efficiency of TiO₂ based photocatalyst such as tuning the bandgap by doping, choosing the proper non-TiO₂ compound according to the energy level offset, structural stability of composite, increasing the heterointerfacial area by capping TiO₂, role of the particle size, were discussed in detail. Furthermore to develop a sustainable photocatalyst for waste water treatment process, the necessity of developing a retrieval and reusable model of TiO₂ based photocatalyst has been suggested. The photocatalytic performances of differently structured TiO₂ based photocatalyst in the degradation of organic dye are been compared and presented in this article.