Regulating the Electronic Configuration of Ruthenium Nanoparticles via Coupling Cobalt Phosphide for Hydrogen Evolution in Alkaline Media

Abstract The strong adsorption of intermediates such as OH∗ and H∗ species on the surface of ruthenium (Ru) significantly impedes its electrocatalytic activity for hydrogen evolution reaction (HER) in alkaline media. Here we propose the introduction of cobalt phosphide (CoP) to efficiently regulate the electronic configuration of Ru. The resultant CoP nanowire array decorated with ultrafine Ru nanoparticles on a conductive carbon cloth substrate (denoted as Ru-CoP/CC) displays comparable catalytic performance to the state-of-the-art Pt/C catalyst for HER in 1 M KOH solution, requiring an extremely low overpotential of only ∼21 mV to achieve a current density of 10 mA cm-2, exhibiting a Tafel slope as low as ∼49 mV dec-1, and maintaining excellent stability over 24 hours of electrolysis. Density functional theory calculations on the simulated charge distribution reveal that the regulation of the surface electronic structure of Ru by CoP decreases the adsorption energy of OH∗ and H∗ intermediates on the surface of Ru and ultimately contributes to the outstanding electrocatalytic activity of the Ru-CoP/CC electrode for HER.