Chemically exfoliated metallic MoS2 nanosheets: A promising supporting co-catalyst for enhancing the photocatalytic performance of TiO2 nanocrystals

Electron-hole separation is a critical step to achieving efficient photocatalysis, towards which use of co-catalysts has become a widely used strategy. Despite the tremendous efforts and demonstrated functions of noble metal co-catalysts, seeking noble metal-free co-catalysts will always be the goal when designing cost-effective, high-performance hybrid photocatalysts. In this work, we demonstrate that MoS2 nanosheets with 1T phase (i.e., octahedral phase) can function as a co-catalyst with multiple merits: (1) Noble-metal-free; (2) high mobility for charge transport; (3) high density of active sites for H-2 evolution on basal planes; (4) good performance stability; (5) high light transparency. As demonstrated in both photocatalytic hydrogen production and Rhodamine B degradation, the developed hybrid structure with TiO2 exhibits excellent performance, in sharp contrast to bare TiO2 and the hybrid counterpart with 2H-MoS2.