In-plane intergrowth CoS2/MoS2 nanosheets: binary metal–organic framework evolution and efficient alkaline HER electrocatalysis

Abstract

The alkaline hydrogen evolution reaction (HER) is an extremely important reaction in energy conversion and electrolytic industries. Pristine MoS₂ exhibits poor alkaline HER activity due to weak water adsorption and dissociation. Precisely manipulating active water dissociation components to form a functional interface with MoS₂ would be an effective strategy. Herein, in-plane intergrowth CoS₂/MoS₂ ultrathin nanosheets have been achieved via a one-step pyrolytic sulfurization of a small-sized Co/Mo-MOF precursor. The in-plane intergrowth structure produced abundant interfaces and modulated the interfacial electronic structure, demonstrating an accelerated water dissociation process. Ultralow overpotentials at both onset (16 mV) and 10 mA cm⁻² (75 mV) have been obtained, which surpass those of most top-rated MoS₂-based materials and are even proximate to those of commercial Pt/C (0 mV at onset and 60 mV at 10 mA cm⁻², respectively). Under a large current density of 400 mA cm⁻², the intergrowth nanosheet exhibited long-term stability, showing potential for applications in alkaline water splitting devices.