Electron-Rich Ru Atoms in Loaded Ru₄Fe Intermetallic Compounds/C Modulate the Kinetics of Neutral Hydrogen Evolution

Intermetallic compounds (IMCs) with long-range atomic-scale ordering are an emerging class of efficient and stable electrocatalytic alloy materials. Compared with disordered alloys, IMCs show a better electronic structure and higher mixing enthalpy. Herein, the ordered Ru₄Fe intermetallic compounds with a diameter of 15 nm on porous carbon (Ru₄Fe IMCs/C) are synthesized by a sol–gel and annealing steps, the interaction of Ru 4d and Fe 3d orbitals produces an anisotropic electron distribution, which facilitates the adsorption of water molecules and accelerates their dissociation, which exhibit excellent hydrogen evolution at all pH values. At the current density of 10 mA cm⁻², the overpotentials of Ru₄Fe IMCs/C are 29, 24, and 36 mV in acidic, neutral, and alkaline media for hydrogen evolution reaction (HER), respectively, superior to that of Pt/C catalysts with a mass loading of 20%. Mechanistic studies suggest that the adsorption Gibbs free energy of *H (ΔG_*H) on Ru₄Fe IMCs/C is closer to 0 eV compared to Ru NPs/C, which facilitates the HER process.