Titanium Dioxide as the Most Used Photocatalyst for Water Purification: An Overview

Titanium dioxide (TiO2), one of the most frequently used materials in general, has emerged as an excellent photocatalytic material for environmental applications. In this review, principles and mechanisms of the photocatalytic activity of TiO2 have been analyzed. Structural and physical specificities of TiO2 nanoparticles, such as morphology, crystal structure, and electronic and optical properties, have been considered in the context of photocatalytic applications. A review of the influence of several factors, such as the type and dimensions of photocatalyst particles, pH of the solution, the influence of oxidants/electron acceptors, and light intensity on photocatalytic properties of TiO2, has been provided. Superhydrophilicity as an intrinsic property of the TiO2 surface was discussed through surface reconstruction on TiO2 during the reversible hydrophilic changes. Additionally, attention was paid to improving the photocatalytic properties of TiO2 particles through aggregation and agglomeration.