Rapid synthesis of carbon-supported CoS2/CoSe2 heterostructures by magnetic induction heating for efficient hydrogen evolution reaction in acidic media

Abstract

Transition metal dichalcogenides have been recognized as promising alternative electrocatalysts to precious metal-based benchmarks for hydrogen evolution reaction (HER), owing to their unique structures, tunable electronic properties and low costs. However, the performance is generally compromised by the sluggish electron-transfer kinetics and limited electrical conductivity. Herein, nanocomposites consisting of CoS₂/CoSe₂ heterostructures supported on N-doped carbon are prepared via magnetic induction heating at 200 A for only 10 s and display an apparent HER activity in 0.5 M H₂SO₄. Among the obtained CoS₂/CoSe₂/NC series, the sample with an S:Se atomic ratio of ca. 1:1 exhibits the best performance, requiring a low overpotential of −187 mV to reach the current density of 10 mA cm⁻², with a low Tafel slope of 40.7 mV dec⁻¹, markedly outperforming the CoS₂ and CoSe₂ counterparts. This is ascribed to the optimized electronic structure and enhanced electrical conductivity due to the formation of the CoS₂/CoSe₂ heterostructures, as evidenced in microscopic and spectroscopic measurements. Consistent results are obtained in theoretical studies based on density functional theory calculations. Results from this work highlight the unique potential of heterostructured materials as viable catalysts for electrochemical energy technologies.