Triggering Exothermic Water Dissociation on Copper via Rhenium Implantation for Enhanced Alkaline Hydrogen Generation

Abstract

Implantation of foreign elements into a host lattice can enhance catalytic activity by modulating electronic properties. Copper (Cu), a low-cost and abundant material, shows great potential in energy conversion applications. However, its high water dissociation energy barrier limits its catalytic performance in alkaline hydrogen evolution reactions (HER). Herein, a highly scalable co-electrodeposition method is presented to enhance the electrocatalytic performance of copper for alkaline HER by incorporating rhenium (Re) into the copper lattice. The incorporated Re improves electrocatalytic activity by promoting exothermic water dissociation and enhancing water adsorption. The optimized catalyst, CuRe-10/CP, achieves an overpotential of 46 mV to drive a current density of 10 mA cm⁻², demonstrating excellent electrochemical stability for 450 h at 50 mA cm⁻² in an alkaline medium (1.0 m KOH). Additionally, the electrochemical activity of the CuRe-10/CP is evaluated in simulated seawater and alkaline seawater, where it exhibited exceptional activity and stability. Electrochemical impedance spectroscopy (EIS), electrochemical surface area measurement (ECSA), and turnover frequency (TOF) analyses confirm the significant enhancement in catalytic performance following Re incorporation. Furthermore, in situ Raman spectroscopy, EIS, and density functional theory (DFT) studies reveal that the Re incorporation into the copper lattice significantly improves the water dissociation and intermediate adsorption. This study gives a scalable strategy for designing platinum group element free electrocatalysts for alkaline hydrogen evolution.