TiO2-based Photocatalysis: Toward Visible Light-Responsive Photocatalysts Through Doping and Fabrication of Carbon-Based Nanocomposites

Elimination of toxic organic compounds from wastewater and provision of safe, clean, and cheap water to communities is currently one of the most important global topics in water-pollution control. TiO₂ has emerged as one of the most fascinating material in the modern era due to its potential catalytic properties. In spite of extensive efforts to apply TiO₂ for environmental remediation, photocatalytic activity in the visible region has remained quite low hence the need to fabricate highly photoactive catalysts through modification of TiO₂ and to apply them for water remediation using the abundantly available solar radiation.

Carbon materials are promising candidates for application as functional materials due to their superior physico-chemical properties. This has prompted investigations into their possible application in environmental clean-up. Nanocomposite assemblies composed of different types and proportions of carbon based materials (i.e., carbon nanotubes, graphene, fullerenes, activated carbon, carbon nanofibers) and TiO₂ have also found widespread applicability in water decontamination studies using UV or visible light. This article surveys the literature and highlights recent progress in the development of TiO₂ and nanocarbon/TiO₂ photocatalysts for water decontamination. The nitty-gritties, on-going challenges, areas of controversy, “hotspots” and possible new directions are outlined in this article.