Carbon-doped TiO2 nanoparticles wrapped with nanographene as a high performance photocatalyst for phenol degradation under visible light irradiation

Abstract

With a view to developing photocatalytic applications under irradiation by visible light, many efforts have been devoted to modifying band structure of TiO2 by doping with metal and non-metal ions. Although doping techniques promote the absorption of visible light, it is usually accompanied by the formation of defect sites. Consequently, photocatalytic activity cannot be improved when the concentration of defects is high. Here we wrapped each of carbon-doped TiO2 (C-TiO2) nanoparticles (NPs) with nano-sized graphene (nGR) for use as a high performance material for the phenol degradation and quantified the enhanced photoelectrochemical properties compared to bare C-TiO2 NPs and C-TiO2 NPs distributed on micro-sized graphene (C-TiO2/μGR). C-TiO2 NPs wrapped with nGR (nGR@C-TiO2) showed outstanding oxidizing power than those of bare C-TiO2 NPs, C-TiO2/μGR and commercial TiO2 (P25). It is proven that nGR@C-TiO2 possesses the low interfacial charge-transfer resistance between C-TiO2 and reactant. As a result, prolonged lifetime of photogenerated charges over the C-TiO2 NPs caused the formation of the larger amount of hydroxyl radicals (OH) with strong oxidizing power for the phenol degradation.