Weakening OH adsorption on Ru sites by Ni alloying for accelerating alkaline hydrogen evolution of an intermetallic Ru3Ni electrocatalyst

Abstract

The development of highly efficient and durable ruthenium-based catalysts for the hydrogen evolution reaction (HER) is essential yet challenging for achieving ampere-level anion exchange membrane water electrolyzers (AEMWEs), as the performance of water electrolyzers typically degrades rapidly under continuous high-current operation. In this work, we present an intermetallic Ru₃Ni electrocatalyst supported on nitrogen-doped mesoporous carbon spheres that can address the problem. Theoretical calculations and operando Raman spectroscopy analysis indicate that the incorporation of Ni weakens the adsorption of OH species on Ru sites, thereby preventing catalyst poisoning and facilitating a thermodynamically favorable water dissociation process. As a result, the catalyst exhibits a low overpotential of 12 mV and a high turnover frequency (TOF) of 3.42 H₂ s⁻¹ at −0.1 V_RHE in 1 M KOH. Furthermore, an anion exchange membrane water electrolyzer assembled with Ru₃Ni/CN as the cathode and RuO₂ as the anode operates at a voltage of 1.70 V with a current density of 0.5 A cm⁻², demonstrating remarkable stability over 140 hours. This strategy offers a new design concept for developing highly active electrocatalysts.