An interface engineering induced hierarchical NiCo/V2O3/C Schottky heterojunction catalyst for large-current-density hydrogen evolution reaction

Abstract

Transition metal alloys composed of earth-abundant elements have received increasing attention as promising catalysts for alkaline hydrogen evolution reaction (HER), emerging as powerful alternatives to noble metal Pt-based catalysts. However, exploring solutions to further improve the catalytic performance of transition metal alloys and solve the problems of agglomeration and dissolution in an alkaline medium still remain a serious challenge. In this work, three-dimensional NiCo/V₂O₃/C nanosheets were synthesized by a one-step hydrothermal method and sequential thermal reduction, which formed a Mott–Schottky heterojunction between the NiCo alloy and V₂O₃ to enhance charge transport, greatly enhancing the alkaline HER. Moreover, the introduction of the carbon layer of the graphite phase as the support of the heterostructure solves the inherent shortcomings of the alloys, greatly strengthens the stability, and provides a necessary guarantee for the realization of industrial applications. Consequently, it achieved remarkable HER catalytic activity with ultralow overpotentials of 23 and 396 mV to drive current densities of 10 mA and 1000 mA cm⁻² in 1 M KOH, respectively. DFT calculation indicates that the heterogeneous interface simultaneously optimizes the free energy of hydrogen adsorption and H₂O adsorption energy, and promotes the kinetics of the HER. More importantly, it also demonstrated excellent durability in constant current tests at a current density of 1000 mA cm⁻² in KOH, illustrating its great potential for industrial application.