Synergetic Effect of MoS2 and Graphene as Cocatalysts for Enhanced Photocatalytic H2 Production Activity of TiO2 Nanoparticles

The production of H-2 by photocatalytic water splitting has attracted a lot attention as a clean and renewable solar H-2 generation system. Despite tremendous efforts, the present great challenge in materials science is to develop highly active photocatalysts for splitting of water at low cost. Here we report a new composite material consisting of TiO2 nanocrystals grown in the presence of a layered MoS2/graphene hybrid as a high-performance photocatalyst for H-2 evolution. This composite material was prepared by a two-step simple hydrothermal process using sodium molybdate, thiourea, and graphene oxide as precursors of the MoS2/graphene hybrid and tetrabutylorthotitanate as the titanium precursor. Even without a noble-metal cocatalyst, the TiO2/MoS2/graphene composite reaches a high H-2 production rate of 165.3 mu mol h(-1) when the content of the MoS2/graphene cocatalyst is 0.5 wt 96 and the content of graphene in this cocatalyst is 5.0 wt 96, and the apparent quantum efficiency reaches 9.796 at 365 nm. This unusual photocatalytic activity arises from the positive synergetic effect between the MoS2 and graphene components in this hybrid cocatalyst, which serve as an electron collector and a source of active adsorption sites, respectively. This study presents an inexpensive photocatalyst for energy conversion to achieve highly efficient H-2 evolution without noble metals.