Three-dimensional CoMoMg nanomesh based on the nanoscale Kirkendall effect for the efficient hydrogen evolution reaction

Abstract

The conversion of excess electrical energy in a power system to hydrogen through the use of water electrolysis is considered an effective alternative to replace fossil fuels. However, the scarcity and high cost of Pt-based materials for the hydrogen evolution reaction (HER) impedes their large-scale application in electric power systems. On the basis of the nanoscale Kirkendall effect, three-dimensional CoMoMg nanomeshes are fabricated by a conventional high-temperature sintering method. The nanomesh CoMoMg alloy mainly consists of intermetallic Co3Mo, which achieves a low overpotential of 36 mV at a current density of 10 mA cm−2 in 1 M KOH. The electrode during a 60,000 s HER process under different current densities, especially 2 A cm−2, displays excellent long-term stability without compromising electrocatalytic activity, which is attributed to the synergistic effect between Co and Mo and three-dimensional nanoporous structure. This work provides a feasible strategy for designing efficient and durable hydrogen evolution electrocatalysts, and effectively solves the problem of expensive Pt-based precious metal catalysts.