Interfacial engineering of 3D hollow CoSe₂@ultrathin MoSe₂ core@shell heterostructure for efficient pH-universal hydrogen evolution reaction

Rational design and construction of low-cost and highly efficient electrocatalysts for hydrogen evolution reaction (HER) is meaningful but challenging. Herein, a robust three dimensional (3D) hollow CoSe₂@ultrathin MoSe₂ core@shell heterostructure (CoSe₂@MoSe₂) is proposed as an efficient HER electrocatalyst through interfacial engineering. Benefitting from the abundant heterogeneous interfaces on CoSe₂@MoSe₂, the exposed edge active sites are maximized and the charge transfer at the hetero-interfaces is accelerated, thus facilitating the HER kinetics. It exhibits remarkable performance in pH-universal conditions. Notably, it only needs an overpotential (η₁₀) of 108 mV to reach a current density of 10 mA·cm⁻² in 1.0 M KOH, outperforming most of the reported transition metal selenides electrocatalysts. Density functional theory (DFT) calculations unveil that the heterointerfaces synergistically optimize the Gibbs free energies of H₂O and H* during alkaline HER, accelerating the reaction kinetics. The present work may provide new construction guidance for rational design of high-efficient electrocatalysts.