Dual-Doping-Induced Symmetry Breaking in NiO Nanosheets Enables Efficient Water Electrolysis

Breaking the symmetry of NiO is highly desirable for enhancing the oxygen evolution reaction (OER) performance yet remaining a huge challenge due to the charge compensation effect of the traditional single-doping strategy. Herein, we present a synergistic anion−cation co-doping strategy to precisely engineer localized symmetry breaking in NiO nanosheets for a high-performance anion exchange membrane water electrolyzer (AEMWE). The Fe,N dual doping disrupts the local Ni−O−Ni coordination, inducing electron redistribution at Ni sites and consequently activating potential catalytic centers. In situ electrochemical spectroscopy and theoretical investigations demonstrate that the targeted structural modulation markedly improves electron transport, optimizing intermediate adsorption and enhancing interface polarization effects. As a result, Fe,N-NiO delivers OER activity with a 320 mV overpotential at 100 mA·cm –2, along with HER performance (83.3 mV at 10 mA·cm –2 ). In AEMWE applications, Fe,N-NiO maintains stable operation for over 170 h at 1 A·cm –2, significantly outperforming conventional NiO-based catalysts. This work pioneers an anion−cation co-doping-driven symmetry engineering approach, establishing a scalable paradigm for highly efficient and stable water electrolysis.