Drastically enhanced visible light-driven H2 evolution by anchoring TiO2 nanoparticles on molecularly grafted carbon nitride nanosheets via a multiple modification strategy.

Abstract

The development of graphitic carbon nitride (CN) based photocatalysts towards efficient visible light-driven H2 evolution is highly desired for solar energy conversion. It is well-known that bulk CN materials possess three intrinsic problems, namely, high charge recombination loss, low specific surface area, and limited sunlight harvesting range. To simultaneously overcome the abovementioned drawbacks of CN, we report an innovative multiple modification strategy, involving molecular grafting of the CN network, exfoliation to ultrathin nanosheets, and hybridization with TiO2 photocatalysts. The visible light utilization ability, specific surface area, and charge separation efficiency of the CN materials improved accordingly. As expected, the TiO2/CNX-NS heterojunction photocatalyst exhibited remarkably enhanced visible light-driven H2 production rate of 138.4 μmol h-1, which was about 4.6 times higher than that of pristine CN. The excellent photocatalytic performance under visible light confirmed the successful improvement in the corresponding drawbacks of CN by each modification. In this study, we propose the possibility of combining multiple modifications in the same system to synthesize an excellent visible light-driven photocatalyst for solar-to-fuel conversion.