Hydrogen Spillover Boosted Hydrogen Evolution Electrocatalysis over Pd@CoP in Alkaline Seawater

Developing efficient and stable electrocatalysts for the hydrogen evolution reaction (HER) is crucial to achieve effective electrolytic hydrogen production from seawater. Hydrogen spillover enhances catalytic performance by facilitating the migration of hydrogen species between different sites, improving reaction efficiency and kinetics in the HER. Herein, we report the hydrothermal-phosphatization-immersion synthesis of Pd-decorated CoP nanoneedle arrays on nickel foam (Pd@CoP/NF) as a highly active HER electrocatalyst toward alkaline seawater reduction. In situ electrochemical impedance spectroscopy and kinetic isotope effects reveal Pd@CoP/NF's extensive hydrogen adsorption and enhanced hydrogen transfer rates. In alkaline seawater, such Pd@CoP/NF exhibits outstanding performance with a low overpotential of 249 mV at a current density of 1000 mA cm–2 and long-term stability for 500 h.