Interfacial built‐in electric fields facilitating surface reconstruction in heterojunction electrocatalysts for boosting water oxidation and simulated seawater oxidation

Monitoring and customizing the dynamic transformation of catalyst in real-world reactions is significant for accurately identifying the active species, clarifying reaction mechanisms, and achieving optimal performance. In this study, we propose an interfacial built-in electric field (BEF) facilitated surface reconstruction strategy to enhance the electrocatalytic OER performance of heterojunction (Fe2P/NiCoP) electrocatalyst with asymmetric charge distribution. This approach accelerates OER kinetics and improves the electrochemical stability. Our findings show that the robust and enduring BEF at the Fe2P/NiCoP interface promotes the surface reconstruction of NiCoP into NiCoOOH active species, influencing the binding energy with intermediates during reactions. Consequently, the catalyst exhibits remarkably low overpotentials of 247 and 255 mV to achieve 10 mA·cm-2 with exceptional stability in alkaline freshwater and simulated seawater electrolyte, respectively. This research highlights the significant impact of BEF on enhancing OER performance through in-situ reconstruction, a concept that could be utilized in the development of other advanced electrocatalysts.