Dynamic construction of a durable epitaxial catalytic layer for industrial alkaline water splitting

Optimizing the catalyst-electrolyte interface structure is crucial for enhancing the performance of electrochemical alkaline hydrogen evolution reaction. Traditional approaches typically focus on regulating the thermodynamic barriers of adsorption and desorption for reactants, intermediates, and ions at active sites on the solid electrode surface. However, the structure of the electrical double layer influences the concentration of intermediates, adsorption energy, and surface reaction kinetics. Here, we dynamically construct a dense epitaxial hydroxide layer on nickel molybdate, forming an effective protective barrier to prevent molybdenum leaching and enhance material stability. This optimization enhances local electric field increasing the concentration of hydrated potassium ions within the outer Helmholtz plane. As a result, the interfacial hydrogen-bond network improves, water availability on the catalyst surface increases, and reaction kinetics accelerate. The optimized material operates stably for 1400 h at a current density of 0.45 A cm−2 in an industrial alkaline electrolyzer. Our dual-optimization strategy of dynamically constructing an epitaxial catalytic layer offers valuable insights for developing stable, high-current-density electrocatalytic materials. Alkaline hydrogen production needs stable catalysts, but the electrical double layer is overlooked. Here, the authors report a dense epitaxial hydroxide layer that strengthens the double layer, prevents catalyst leaching, and enhances material stability for 1,400 h in an industrial electrolyzer.