Engineering Boundary Electronic Supply for Boosted Overall Water Splitting

Electrocatalytic hydrogen evolution via water splitting occurs at the electrode surface, particularly at the solid–liquid interfaces. Establishing boundary electron transfer channels is crucial for accelerating water molecule adsorption and mass transfer and achieving adsorption–desorption equilibrium of intermediate products. Drawing inspiration from the structure of a starfish, we constructed a starfish-tentacle-like CoP/Co2Fe1P/CC heterostructure on a carbon cloth substrate using ZIF as the precursor. This design aimed to enhance the boundary electron transfer capability, providing more interface active sites and thereby accelerating proton transfer and transport. As anticipated, the CoP/Co2Fe1P/CC catalyst exhibited exceptional performance in both hydrogen and oxygen evolution reactions. It required only a 73 mV overpotential for hydrogen evolution and 253 mV overpotential for oxygen evolution at a current density of 10 mA cm–2. Notably, it achieved a low voltage of 1.49 V for sustained overall water splitting, surpassing most state-of-the-art transition metal phosphide-based catalysts.