Use of TiO2 in Photocatalysis for Air Purification and Wastewater Treatment: A Review

Abstract

This study reviews recent research on the synthesis and application of titanium dioxide (TiO2)-based photocatalysts for environmental applications. The principles of non-homogenous photo-catalysis include utilizing a solid semiconductor, such as titanium dioxide Nano or macro, to form a stable suspension (heterogeneous phase) at the impact of irradiation to elevate a reaction at the surface interface of the different phases in the system. Recently, titanium dioxide has been considered the better semiconductor in non-homogenous photoinduced treatment. TiO2-based photocatalysts have broad applications for industrial processes because of their exceptional physicochemical properties. Nevertheless, having a narrow band near the ultraviolet region limits its applications within visible radiation. As a result of this, there have been considerable research efforts to improve the visible light tendency of TiO2 through modifications of its optical and electronic properties. Several strategies, such as coupling TiO2 tightly and incorporating other metallic components during synthesis, have increased the bandgap of TiO2 for visible light applications. Moreover, an overview of nanotechnology that could enhance the properties of TiO2-based catalysts in an environmentally friendly way to decompose pollutants is also presented. The various TiO2-based photocatalysts have wide applications in degrading recalcitrant pollutants in the air, water, and wastewater treatment under visible light.