Synergistic effect of reduced graphene oxide and near-infrared light on MoS2-mediated electrocatalytic hydrogen evolution

Abstract

• rGO-MoS 2 composite with remarkable NIR light response was obtained. • rGO-MoS 2 exhibited good and stable HER performance in a wide pH range. • rGO and NIR light have synergistic effect on the photoelectrocatalysis of MoS 2 . • The photoelectrocatalytic HER mechanism by rGO-MoS 2 under NIR light is proposed. This work presents an effective way of enhancing MoS 2 -mediated electrocatalytic hydrogen evolution, by exploiting the synergistic effect of reduced graphene oxide (rGO) and near-infrared (NIR) light. Various rGO-MoS 2 composites were obtained via hydrothermal method. The optimized composite, 0.2rGO-MoS 2 exhibited enhanced electrocatalytic hydrogen evolution activity in a wide pH range under NIR irradiation, without adding noble metal. The overpotentials of 0.2rGO-MoS 2 at 10 mA cm −2 in acidic and alkaline media were 146 and 314 mV, respectively. The corresponding Tafel slopes in acidic and alkaline media were 51 and 80 mV dec −1 , respectively. In both media, the electrocatalytic hydrogen evolution by 0.2rGO-MoS 2 under NIR irradiation was attributed to the Volmer-Heyrovsky mechanism. 0.2rGO-MoS 2 also had a good reproducibility and durability under NIR light irradiation after 5000 cycles and 24 h of continuous electrolysis in both media. Furthermore, the roles of rGO and NIR irradiation in the electrocatalytic hydrogen evolution by MoS 2 were investigated.