Hierarchical Core-Shell Cu@Cu-Ni-Co Alloy Electrocatalyst for Efficient Hydrogen Evolution in Alkaline Media

The development of advanced electrocatalysts plays a pivotal role in enhancing hydrogen production through water electrolysis. In this study, we employed a two-step electrodeposition method to fabricate a 3D porous Cu-Co-Ni alloy with superior catalytic properties and long-term stability for hydrogen evolution reaction (HER). The resulting trimetallic alloy, Cu@Cu-Ni-Co, demonstrated significant improvements in structural integrity and catalytic performance. A comparative analysis of electrocatalysts, including Cu, Cu@Ni-Co, and Cu@Cu-Ni-Co, revealed that Cu@Cu-Ni-Co achieved the best results in alkaline media. Electrochemical tests conducted in 1.0 M NaOH showed that Cu@Cu-Ni-Co reached a current density of 10 mA cm⁻² at a low overpotential of 125 mV, along with a low Tafel slope of 79.1 mV dec⁻¹. The catalyst showed exceptional durability, retaining ~95% of its initial current density after 120 h of continuous operation at high current densities. Structural analysis confirmed that the enhanced catalytic performance arises from the synergistic interaction between Cu, Ni, and Co within the well-integrated trimetallic framework. This integration results in a large electrochemical active surface area (ECSA) of 380 cm² and a low charge transfer resistance (15.76 Ω), facilitating efficient electron transfer and promoting superior HER activity. These findings position Cu@Cu-Ni-Co as a highly efficient and stable electrocatalyst for alkaline HER in alkaline conditions.