Tuning the electronic structure of Co@N–C hybrids via metal-doping for efficient electrocatalytic hydrogen evolution reaction

Abstract

Hydrogen evolution reaction (HER) electrocatalysts that are free of noble metals are highly desirable for energy conversion applications. Herein, a general hydrothermal–impregnation–pyrolysis process is proposed to introduce W into Co nanoparticles surrounded by N-doped carbon to obtain CoW@N–C hybrids supported on nickel foam (NF) as high-efficiency HER electrocatalysts (CoW-py-T@NF). The experimental and calculation results show that the introduced W atoms could optimize the electronic structure of Co@N–C, which is conducive to charge transfer, reaction kinetics, and active site exposure, as well as intrinsic activity enhancement. As a result, the obtained Co1.5W0.5-py-500@NF exhibits excellent HER performance, achieving current densities of 25 and 100 mA cm⁻² in 1.0 M KOH, requiring only extremely low overpotentials of 55 and 100 mV, respectively. Importantly, this fascinating strategy can be applied to other metals (M = Cr, Mo, or Ce) to obtain CoM@N–C HER electrocatalysts with high efficiency.