Interface-engineered crystalline CoFe-LDH/amorphous NiFe-LDH heterostructure for efficient alkaline oxygen evolution

The advancement of alkaline water electrolysis relies on creating efficient, durable, and affordable electrocatalysts for the oxygen evolution reaction (OER). Here, we reported a heterostructured CoFe/a-NiFe LDH catalyst that integrates amorphous NiFe layered double hydroxide (LDH) with crystalline CoFe LDH through interface engineering. The CoFe/a-NiFe LDH catalyst achieved superior activity with an overpotential of 265 mV at 100 mA·cm −2 , which outperformed the commercial RuO 2 . It also demonstrated rapid kinetics with a Tafel slope of 38.8 mV·dec −1 . The synergistic coupling between the crystalline domains and amorphous regions minimized charge transfer resistance while maximizing electrochemically accessible sites. Remarkably, the catalyst showed outstanding durability, operating consistently for 220 h at demanding current densities of 100 mA·cm −2 . This work established amorphous-crystalline interface engineering as a powerful strategy for designing high-performance water oxidation electrocatalysts.