Effective charge separation towards enhanced photocatalytic activity via compositing reduced graphene oxide with two-phase anatase/brookite TiO2

In this paper, we synthesized composites consisting of reduced graphene oxide (rGO) and two-phase anatase/brookite TiO2 particles. Results showed that with the addition of rGO to anatase/brookite TiO2, the photocatalytic H-2 production from aqueous methanol solution over Pt loaded catalyst is greatly enhanced. This is attributed to effective charge separation leading to the inhibition of photogenerated electron-hole recombination as evidenced from photoluminescence (PL) spectroscopic measurement. Moreover, with the rGO - anatase/brookite TiO2 composite, the H-2 production is 2.3 times the amount of H-2 produced by rGO - P25 TiO2 (which consists of anatase and ruffle particles) composite. The comparison illustrates the importance of the conduction band potential position. As the conduction band potential of brookite TiO2 is more cathodic than anatase and rutile TiO2, it is energetically more favorable for reductive hydrogen production. Through the concept of compositing rGO with two-phase semiconductor photocatalyst, our work has elucidated the importance of effective charge transfer as well as conduction band potential position in photocatalytic hydrogen generation. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.