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Controlling active phase reconstruction is critical for enhancing the oxygen evolution reaction (OER) performance in water electrolysis. In this study, a series of catalysts D-Ni/NiMO (M = Fe, Co, Mn) with varying M–O bond lengths were synthesized using nickel oxide as a model electrocatalyst. Among them, Ni/NiCoO, featuring the longest M–O bond length, received particular attention. Comprehensive in situ and ex situ characterizations, including synchrotron radiation X-ray absorption spectroscopy, revealed that elongation of M–O bonds promotes the dynamic formation of active OER phases. A quantitative relationship was established: longer M–O bond lengths correlate with improved catalytic performance. Mechanistic studies revealed that stretched M–O bonds facilitate electron depletion from the z 2 orbital, enhancing metal–oxygen electron delocalization, and promoting the generation of highly active species (e.g., high-valent Ni 3+ ) during the reconstruction process. As a result, the D-Ni/NiCoO catalyst exhibits superior OER performance, requiring an ultralow overpotential of only 300 mV at a current density of 100 mA cm –2, while maintaining long-term stability over 60 h. Under industrially relevant operating conditions, the fully assembled D-Ni/NiCoO||Pt/C device showcased a superior performance profile, requiring a cell voltage of just 2.1 V to achieve 1000 mA cm –2 and demonstrating robust operational durability for 50 h. This study provides fundamental insights into the relationship between M–O bond lengths and active phase reconstruction, offering a rational strategy for designing high-performance OER catalysts suitable for operation under industrial-level current densities.
Liu et al. (Thu,) studied this question.