In situ constructed defect-rich interfaced Mn1Fe3 PBA@NiFe LDH self-supported electrode for efficient oxygen evolution reaction

The rational design of high-efficiency OER electrocatalysts with low cost remains a key challenge. In this work, hydrangea-like nickel-iron layered double hydroxides (NiFe LDH) were prepared via a hydrothermal approach, followed by the in situ anchoring of cubic-shaped anganese-iron Prussian blue analogue (MnFe PBA) nanocubes on their surface. This strategy successfully yielded a Mn1Fe3 PBA@NiFe LDH composite with abundant defects and well-defined heterointerfaces. The resulting catalyst exhibits excellent OER activity in 1.0 M KOH electrolyte, requiring an overpotential of only 225 mV to reach 10 mA cm −2 and delivering a Tafel slope as low as 46.4 mV dec −1 , indicative of favorable reaction kinetics. Notably, the catalyst retains its performance over 150 h of continuous operation at 100 mA cm −2 , confirming its long-term operational stability. These superior properties primarily originate from the unique hierarchical channel structure, abundant oxygen vacancies (OVs), and hollow structural defects in the cubic architecture, which collectively expose more active sites and significantly enhance electron transfer capability. Additionally, the well-crystallized Mn1Fe3 PBA phase effectively inhibits the rapid dissolution of NiFe LDH during OER processes, thus mitigating activity loss. This work provides a novel design strategy for interfacial integration of LDH and PBA to develop high-efficiency OER electrocatalysts.