Phase-engineered multiscale synergistic modulation in amorphous-sheathed crystalline electrocatalysts for bifunctional water splitting

Interfacial engineering holds great potential for water electrolysis catalysts, but the precise manipulation of interfacial electronic configurations and the maintenance of structural integrity remain a formidable challenge. Herein, we propose an innovative synthetic strategy to prepare nanorod array materials with an amorphous/crystalline core–shell structure (CoPA_-0.5@CuO_-300) through a simple and mild process. The resulting materials exhibited excellent electrocatalytic properties and significantly accelerated the kinetics of the reaction. Through rigorous experimental characterization and theoretical calculations, we elucidated three synergistic mechanisms: (1) the electronic reconfiguration of the non-homogeneous interfaces effectively reduces the reaction energy barriers; (2) The nanorod array structure significantly enhances the electrochemically active surface area, thereby providing a greater number of catalytic sites; and (3) the amorphous outer layer, due to its disordered structure, facilitates the adsorption/ desorption. By leveraging this synergistic effect, CoPA_-0.5@CuO_-300 demonstrated outstanding electrocatalytic performance under 1 M KOH conditions, achieving Oxygen evolution reaction (OER) and Hydrogen evolution reaction (HER) overpotentials of only 159 mV and 119 mV, respectively, at a current density of 10 mA cm⁻². Moreover, the catalyst retained over 98 % of its initial activity after 60 h of continuous operation. This work presents an innovative structural design approach that offers a novel pathway for developing highly efficient and durable non-homogeneous interfacial electrocatalysts.