Bimetallic active site nuclear-shell heterostructure enables efficient dual-functional electrocatalysis in alkaline media

Abstract

Hydrogen, as a green and clean next-generation fuel, is a key to achieving the goal of carbon neutrality. Constructing an electrocatalyst with bifunctional hydrogen evolution and oxygen evolution activity in the same electrolyte is a key technology for producing hydrogen via water splitting. Herein, a bimetallic active site catalyst, which possessed an edge-riched MoS₂ nanoflakes array vertically growing on cubic CoS₂, forming a nuclear-shell heterogeneous configuration, termed CSC-MoS₂@CoS₂. was reported The optimal CSC-MoS₂@CoS₂-24 possessed good dual-functional electrocatalytic activity (hydrogen evolution (HER), 10 mA·cm⁻²@241.5 mV and oxygen evolution (OER), 10 mA·cm⁻²@350 mV). Especially, CSC-MoS₂@CoS₂-24 exhibited an extremely high mass activity for HER, and only required an overpotential of ~ 550 mV when reaching a large current density of 1422 mA·mg⁻¹, which was 20.6-fold that of the bulk CoS₂ (69 mA·mg⁻¹), as well as exhibiting stability of up to 100 h. The good electrocatalytic performance was attributed to the nuclear-shell heterostructure of MoS₂@CoS₂ hybrid could bring critical synergies, improving efficient mass transfer and electron transfer processes between CoS₂ and MoS₂, which collaboratively promoted the electrocatalytic kinetics. It is foreseeable that the method proposed in this work will have guiding value for the preparation of dual-functional electrocatalysts with multi-interface heterostructures by assembling layered sulfides on cubic sulfides.

Graphical abstract