Ru Regulated Electronic Structure of Pd_xCu_y Nanosheets for Efficient Hydrogen Evolution Reaction in Wide pH Range

The development of highly effective catalysts for hydrogen evolution reaction (HER) in a wide pH range is crucial for the sustainable utilization of green energy utilization, while the slow kinetic reaction rate severely hinders the progress of HER. Herein, the reaction kinetic issue is solved by adjusting the electronic structure of the Ru/Pd_xCu_y catalysts. The champion catalyst displays a remarkable performance for HER with the ultralow overpotential (27, 28, and 97 mV) in 1.0 m KOH, 0.5 m H₂SO₄, and 1.0 m PBS at 10 mA cm^-2 and high the mass activity (3036 A g^-1), respectively, superior to those of commercial Pt/C benchmarks and most of reported electrocatalysts, mainly due to its low reaction activation energy. Density functional theory (DFT) calculations indicate that Ru doping contributes an electron-deficient 3d band, which promotes water adsorption. Additionally, this also leads to an upward shift of the d-band center of Pd and a downward shift of the d-band center of Cu, further optimizing the adsorption/dissociation of H₂O and H^*. Results from this work may provide an insight into the design and synthesis of high-performance pH-universal HER electrocatalysts.