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.