Core-shell structured CoFe-PBA@NiFe-LDH as efficient electrocatalysts for oxygen evolution reaction

NiFe-based layered double hydroxide (NiFe-LDH) nanosheets were hydrothermally anchored onto the surface of CoFe-based Prussian blue analogue (CoFe-PBA) nanocubes, resulting in the formation of core-shell-structured CoFe-PBA@NiFe-LDH. Electrochemical characterizations revealed that this material exhibits exceptional oxygen evolution reaction (OER) activity coupled with remarkable long-term stability in alkaline media. The optimized CoFe-PBA@NiFe-LDH catalyst achieves a low OER overpotential of 287 mV to reach a current density of 10 mA cm^-2, accompanied by a favorable Tafel slope of 77 mV dec^-1. Notably, the catalyst can maintain the initial catalytic activity even after 18 h of continuous operation, with its morphology and crystalline structure remaining well-preserved. The superb electrocatalytic performance is fundamentally attributed to the synergistic core-shell architecture, where the uniform decoration of NiFe-LDH nanosheets on CoFe-PBA nanocubes maximizes the exposure of abundant and highly accessible active sites while facilitating the mass transport of reactive intermediates.