Metal-ion bridged high conductive RGO-M-MoS₂ (M = Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺) composite electrocatalysts for photo-assisted hydrogen evolution

Efficient photo-electrocatalysts for hydrogen evolution reaction (HER) are synthesized using a facile one-step hydrothermal method. With metal-ion bridges, highly dispersed molybdenum disulfide (MoS₂) nanolayers are vertically grown on the reduced graphene oxide (RGO) to form RGO-M-MoS₂ photocatalysts for HER, where M = Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺. The results show that the cross-bridging ions can modulate the MoS₂ growth priority and act as efficient charge transfer channels between RGO and MoS₂, and combine the advantages of the high conductivity of graphene with the photo-electrochemical activity of MoS₂. The metal-ion bridged MoS₂-M-RGO heterostructures demonstrate superior catalytic activity toward hydrogen evolution reaction in acid medium, evidenced by the remarkable higher catalytic current density at low overpotential compared with that of MoS₂-RGO without metal-ion bridge. This study provides a novel and facile route for establishing efficient composite photo-electrocatalysts for water splitting to generate hydrogen.