Constructing GO films/CdS nanoparticles/MoS2 nanosheets ternary nanojunction with enhanced photocatalytic hydrogen evolution activity

Abstract

CdS, as a visible-light responsible photocatalyst, has gained considerable attentions for its relatively narrow bandgap and negative conduction band edge. However, its photocatalytic activity is hindered by challenges such as severe charge recombination, insufficient active sites and poor stability. In this work, a robust strategy is proposed to optimize the transfer channel for charge carriers and enhance the active sites by heterojunction and cocatalyst engineering. The well-designed GO/CdS/MoS2 shows remarkable durability (20 h without significant loss of H2 production rate) with a high photocatalytic H2 production rate of 1.45 mmol h−1g−1 (about 6.6-fold enhancement compared with CdS) at GO content of 0.1 wt% and MoS2 loading amount of 5.0 wt%. The bolstered H2 production rate is attributed to the augmented transfer channels of mass owing to the holey structure of GO, the enhanced active sites since the introduction of MoS2, and the unidirectional transfer of electrons from CdS to MoS2, which is ascribed to the built-in electric field in the CdS/MoS2 interface. Thanks to the directional transfer of holes from CdS to GO in the GO/CdS interface, the assemblage of holes in CdS is prevented, thus contributing to the amplified stability GO/CdS/MoS2. Our findings offer insights for the enhanced photocatalytic activity of CdS based photocatalysts, which may inspire the development of the heterostructure photocatalysts for solar-to-fuel conversion.