Optical properties of metal-molybdenum disulfide hybrid nanosheets and their application for enhanced photocatalytic hydrogen evolution.

Limited control over charge recombination between photogenerated charge carriers largely hinders the progress in photocatalysis. Here, we introduce metal nanoparticles (Cr, Ag) to the surface of MoS2 nanosheets by simple synthetic means creating a hybrid metal-MoS2 nanosheet system with well-defined metal/semiconductor interfaces. We demonstrate that this hybrid nanosheet structure is capable of decoupling light absorption, primarily in MoS2, and carrier separation, across the metal-MoS2 heterostructure leading to drastic quenching of recombination between photogenerated carriers in MoS2, as proven by absorptance, photoluminescence, and ultrafast pump-probe spectroscopy. The photocatalytic activity in the hybrid system is also improved, which further shows excellent stability against photocorrosion.