Iridium-Cluster-Implanted Ruthenium Phosphide Electrocatalyst for Hydrogen Evolution Reaction

Abstract

Ruthenium phosphide is a promising catalyst for hydrogen evolution due to its cost-effectiveness compared to platinum. However it faces the challenge of having a high binding energy for hydrogen intermediates. In this study, we demonstrate that the incorporation of iridium in ruthenium phosphides lowers the binding energy of hydrogen intermediates, thereby controlling the overpotential and Tafel slope of hydrogen evolution. When the Ir content was doped at 3 at.%, the catalyst achieved an overpotential of 33 mV and a Tafel slope of 33 mV dec⁻¹ under acidic conditions, which are similar to those of the benchmark Pt/C catalyst. In situ Raman spectroscopy and density functional theory (DFT) calculations suggest that the enhanced catalytic activity originates from the near-neutral Gibbs free energy of hydrogen adsorption on the hollow site of the iridium cluster implanted onto ruthenium phosphide.