关键词: 镍铜合金, 镍钒氢氧化物, 析氢反应, 本征活性, 协同效应

Abstract: Given the urgent demand for non-precious metal electrocatalysts in the hydrogen production field, developing efficient, stable, and low-cost hydrogen evolution electrode materials is a key challenge for achieving sustainable water electrolysis for hydrogen generation. Using nickel mesh (NM) as the substrate, a three-dimensional porous composite catalyst comprising cobalt–vanadium layered hydroxide and a nickel-copper alloy (CoV LDH/NiCu/NM) was fabricated via a combined approach of hydrogen bubble dynamic template electrodeposition and cyclic voltammetry. The resulting material features an open porous architecture constructed from intertwined nanodendrites and stacked circular nanosheets, with nickel–copper alloy and cobalt-vanadium hydroxide as the primary crystalline phases. This unique structure significantly enhances the specific surface area, yielding an electrochemical active surface area (ECSA) approximately 110 times higher than that of the bare NM substrate, thereby providing abundant catalytic sites and efficient mass transfer pathways for water electrolysis. Benefiting from synergistic multi-component and structural effects, the CoV LDH/NiCu/NM electrode exhibits exceptional hydrogen evolution reaction (HER) performance in 1 mol·L^-1 KOH electrolyte. Specifically, it delivers low overpotentials of 28 and 108 mV at current densities of 10 and 100 mA·cm^-2, respectively, along with a Tafel slope of 47.1 mV·dec^-1, indicating favorable reaction kinetics. The catalyst also exhibits good oxygen evolution reaction (OER) activity and enables overall water splitting (OWS) with the overpotential of 329 mV and cell voltage of 1.506 V at 10 mA·cm^-2, respectively, demonstrating its potential as a bifunctional electrode. Moreover, the catalyst demonstrates outstanding long-term durability, with negligible degradation in overpotential after 72 h of continuous operation at 100 mA•cm^-2. Structural and electrochemical analyses reveal that the superior catalytic activity is primarily attributable to the well-defined porous nanosheet architecture. This work presents a promising strategy for the design of high-performance, noble-metal-free electrocatalysts for hydrogen evolution.

Key words: nickel-copper alloy, cobalt-vanadium hydroxide, hydrogen evolution reaction, intrinsic activity, synergistic effect