Dynamic Reconstruction‐Engineered Heterointerfaces for Acidic Hydrogen Evolution at Ampere‐Level Current Density

The industrial application of proton exchange membrane electrolysis for hydrogen production urgently requires acidic hydrogen evolution reaction (HER) catalysts that combine high activity with long lifespan at ampere‐level current densities. This work employs electrochemically driven dynamic reconstruction to in situ transform self‐supporting Cu 3 P nanowires into a core–shell structure with a loose surface layer consisting of PtCu/Cu 3 P heterostructures. The reconstructed catalyst exhibits benchmark HER performance in acid, requiring low overpotentials of only 37.8 and 207.8 mV at 10 and 1000 mA cm −2 , respectively, while maintaining stable operation for over 240 h at 1000 mA cm −2 . Mechanistic studies reveal that the heterointerface synergistically regulates hydrogen adsorption free energy and facilitates proton transport, while the loosely porous morphology formed by reconstruction ensures efficient mass transfer at high currents. The catalyst's exceptional durability stems from the dynamic dissolution‐redeposition equilibrium of surface metal species during operation. This work reveals a novel reconstruction pathway in acid involving foreign metal participation, enabling industrial‐scale acidic HER catalysis.