Carbon decorated In2O3/TiO2 heterostructures with enhanced visible-light-driven photocatalytic activity

Abstract

Titanium dioxide (TiO2) has been observed to solve environmental pollution and energy crisis, but its large band gap and high rate of charges combination impede its application. Narrowing band gap and enhancing separation of photoinduced electron-hole pairs are still a challenging task. Creating the heterojunction between different substances is an effective method. Meanwhile, doping TiO2 with carbon is an efficient technique to reduce band gap and facilitate charges’ transfer. In this study, carbon modified In2O3/TiO2 heterostructures are prepared via a facile incipient wet impregnation method. Doping TiO2 with carbon produces an additional carbon-doping level above valence band (VB) of TiO2 causing it to be excited under visible light, and forms heterojunction between In2O3 and TiO2, which suppresses recombination of photoexcited electrons and holes and promotes migration of charge at the interface. Furthermore, ternary nanocomposite exhibits an effective separation and migration performance of photoinduced electrons and holes, and it shows enhanced photoactivity compared with pure P25 when it is applied to photocatalytically remove elemental mercury (Hg0) under visible light irradiation. The possible charge transfer and photocatalytic reaction mechanism are proposed based on characterization and experimental results. In view of the enhanced photocatalytic performance of as-prepared sample, combination of carbon and In2O3 doped into TiO2 support is a promising method to improve the photoactivity. Meanwhile, this method has a tremendous assist on designing and preparing newly effective photocatalyst and large-scale industrial applications.