Effective charge separation and enhanced photocatalytic activity by the heterointerface in MoS2/reduced graphene oxide composites

MoS2/reduced graphene oxide (rGO) composites were fabricated via a facile one-step hydrothermal reaction. In the composites, MoS2 clusters composed of several nanosheets are intertwined tightly with rGO sheets. As the amount of rGO in the composites is increased, the crystallinity of MoS2 changes little, but the diameter of MoS2 clusters decreases considerably and they become more dispersive, resulting in a large specific surface area. As compared to the bare MoS2, the as-prepared MoS2/rGO composites exhibit remarkably enhanced light adsorption and photocatalytic activity for the degradation of Rhodamine B (RhB) under visible light irradiation. Photoluminescence (PL) spectra measurements suggest that the enhanced photocatalytic properties can be ascribed to the effective charge separation across the heterointerface in MoS2/rGO composites. It is also demonstrated that the optical and photoelectric properties of two-dimensional (2D) materials could be substantially enhanced by the heterojunction with an appropriate band edge alignment, since they possess the largest specific surface area.