Dynamic Restructuring of Asymmetric Built-in Electric Field Catalysts Facilitates the Efficient Water Splitting

Efficient and stable bifunctional catalysts for hydrogen and oxygen evolution reaction play an important role in realizing hydrogen economy. In this study, the multi-heterogeneous interfacial catalyst, Ni₂P@FeP@Co₂P (denoted as NFC), with an asymmetric built-in electric field is successfully designed and synthesized. Benefiting from the double charge balance effect, NFC exhibits superior hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) catalytic activity. Importantly, the NFC-assembled anion-exchange membrane (AEM) electrolyzer exhibits enhanced performance and remarkable stability at industrial current densities and high temperatures, reaching a current density of 1000 mA cm⁻² at the small voltage of 1.95 V. The results of the dynamic X-ray photoelectron spectroscopy tests indicate that the self-reconfiguration of the NFC during OER provides additional active sites for the reaction. The density functional theory (DFT) results demonstrate that the asymmetric built-in electric field (BIEF) induces an adaptive distribution of charge, which optimizes the adsorption and desorption of hydrogen/oxygen intermediates during the reaction, thereby enhancing the catalytic kinetics of the overall water splitting process. This work presents novel strategies for the design of highly active catalysts in the field of energy conversion.