TiO2-Based Nanocomposites for Photodegradation of Organic Dyes

The semiconductor metal oxide consisting of TiO2 nanoparticles has been applied for the environmental remediation of toxic substances from environmental samples. TiO2 nanoparticles have been used as a photocatalyst for the degradation of organic pollutants in wastewater samples and have demonstrated potential as an effective photocatalyst. This includes applications for the decontamination of compounds from contaminated samples under both UV and visible light irradiation. Although these nanoparticles have been easily utilized for this application, the electron–hole recombination rate and bandgap energy level could be very high. There are therefore numerous reports on TiO2 nanoparticles coated onto biopolymers of chitosan, alginate, and carboxymethyl cellulose and conducting polymers of polypyrrole, polythiophene, and polyaniline to give polymer TiO2 nanocomposites as the photocatalyst. Such studies have been implemented for the photocatalytic degradation of organic dyes under UV and visible light irradiation in an attempt to improve the photocatalytic activity by lowering the electron–hole recombination rate and the bandgap energy. Moreover adsorptive photocatalytic degradation is favored since this provides a surface onto which the pollutants are adsorbed first and thereafter undergo photocatalytic degradation. This chapter therefore provides an overview of TiO2 as a photocatalyst with respect to its advantages and disadvantages. In a critical review in the recent trends on supporting TiO2, other support materials are discussed, and future research perspectives are also critically evaluated.