Document Type : Review Paper


1 Chemical engineering department. University of technology

2 Chemical Engineering Department, Faculty of Engineering, University of Technology, Iraq

3 Chemical Engineering Dept., University of Technology-Iraq, Alsina’a street,10066 Baghdad, Iraq.


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.

Graphical Abstract


  • The advantages of TiO2 -based as a photocatalyst are reviewed in this study.
  • The development of the group gap in photocatalyst (TiO2) by different doping was investigated.
  • Modification in the structure across the photocatalytic activity of TiO2 is reviewed.
  • Different preparation methods and applications of the Methodology of photocatalysts were also reviewed


Main Subjects

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