Improving the Electrocatalytic Activity of a Core/Shell\nNiCo–ZIF@PBA Catalyst by Co–O–Fe Bridge Bonds\nfor Water Oxidation

In\nresponse to the limitations of slow reaction kinetics and elevated\noverpotentials in the OER, a novel core–shell structured electrocatalyst,\ntermed NiCo–ZIF-67@Fe–Co–Ni-PBA or NiCo–ZIF@PBA,\nhas been developed. This material demonstrates exceptional catalytic\nperformance, exhibiting a minimal overpotential of approximately 188\nmV at 10 mA cm<sup>–2</sup>, alongside a Tafel slope of 109\nmV dec<sup>–1</sup>. Its robust stability in a 1 M KOH solution\nduring the OER operations is noteworthy. Theoretical insights from\nDFT calculations reveal that a Co–O–Fe bridging configuration\nwithin NiCo–ZIF@PBA lowers the energy barrier for the reaction\nto 1.79 eV, a significant reduction from 2.67 eV observed with NiCo–ZIF-67.\nThe improvement in electrochemical performance is primarily due to\nthe emergence of Co<sup>3+</sup> ions, which results from the efficient\ncharge transfer occurring at the interface of the PBA and NiCo–ZIF\ncore–shell structure. These findings suggest a promising strategy\nfor designing advanced core–shell materials for electrocatalytic\napplications.