Edge-sulfonated graphene-decorated TiO2 photocatalyst with high H2-evolution performance

Graphene as a prospective cocatalyst can obviously promote the photocatalytic H2-evolution performance of photocatalysts by rapidly transferring photogenerated electrons. For an efficient graphene-modified photocatalytic system for H2 evolution, the fast H2-evolution reaction is as important as the rapid photoelectron transfer via graphene. In this paper, edge-sulfonated graphene (rGO-SO3H) with high H+-adsorbed activity was successfully synthesized by the formation of covalent bonds between graphene and benzenesulfonic acid through a diazotization reaction, which couples with TiO2 nanoparticles to prepare rGO-SO3H/TiO2 photocatalyst for accelerating H2-evolution reaction. The results showed that the rGO-SO3H/TiO2 displayed the highest H2-production rate of 197.1 μmol h−1 g−1 as high as 5.38, 2.81, and 3.40 times of TiO2, rGO/TiO2, and SO3H/TiO2, respectively. The improved efficiency of rGO-SO3H/TiO2 can be attributable to the synergetic action of graphene as a photoelectron cocatalyst and sulfonate ions as H+-adsorbed active sites. This study provides a new insight for the efficient hydrogen-evolution graphene-based photocatalysts.