Developing efficient and durable oxygen evolution catalysts is vital for advancing anion exchange membrane water electrolysis (AEMWE). Herein, a series of Ni1−xFexSe (x = 0.1, 0.25, and 0.5) nanorod arrays with tunable Fe/Ni ratios were synthesized through one-step selenization of commercial Ni-Fe foams to uncover the intrinsic influence of Fe content on activity and stability. The optimized Ni0.75Fe0.25Se achieves an ultralow OER overpotential of 302 mV at 1000 mA cm−2 with negligible degradation over 500 h. When employed as the anode in an AEM water electrolyzer, the Ni0.75Fe0.25Se/NIF electrode delivers a low cell voltage of 1.73 V at 1000 mA cm−2 and maintains stable operation for over 1300 h with an ultralow voltage decay rate of 54 μV h−1. Structural and spectroscopic analyses demonstrate that a moderate Ni/Fe ratio effectively optimizes the electronic structure of Ni1−xFexSe, while the in situ formed interfacial interlayer markedly enhances structural robustness. More importantly, the Fe/Ni ratio dictates the electrochemical reconstruction of Ni1−xFexSe precatalysts into active NiFeOOH under practical AEMWE conditions, while moderate Fe incorporation promotes well-controlled reconstruction, balances defect chemistry, optimizes the electronic structure, and thereby enhances both intrinsic OER activity and long-term stability.
Zhu et al. (2026) studied this question.