Spinel nickel ferrite (NiFe₂O₄) emerges as a promising low-cost catalyst for water splitting but it usually shows low catalytic activity because of its limited number of active sites and poor conductivity. For the first time, herein we have successfully overcome its weaknesses using defect engineering approach by creating oxygen vacancies in NiFe₂O₄. The existence of oxygen vacancy not only shifts up the d-band center, strengthens the adsorption of H₂O, and thus provides more active catalytic sites, but also tunes the electron configuration and creates massive number of defective donor states in the band gap to facilitate charge transfer processes. The optimal defective catalyst showed significantly enhanced catalytic OER performance with an OER overpotential as low as 0.35 V at 10 mA cm⁻² and a Tafel slope of only ∼40 mV dec⁻¹. Moreover, the impressive specific mass and area current density of 17.5 A g⁻¹ and 0.106 A m⁻² at 1.58 V vs. RHE have been achieved, which are ∼23 and ∼36 times higher than that of defect-free counterpart, respectively.

尖晶石型镍铁氧体（NiFe ₂ O ₄）作为一种有前景的低成本水分解催化剂出现，但由于其活性位点数量有限且电导率较差，通常显示出较低的催化活性。在这里，我们首次通过使用缺陷工程方法通过在NiFe ₂ O _4中产生氧空位成功地克服了其缺点。氧空位的存在不仅使d带中心上移，还增强了对H ₂的吸附。O，因此提供了更多的活性催化位点，而且还调节了电子构型，并在带隙中产生了大量有缺陷的供体态，以促进电荷转移过程。最佳的缺陷催化剂表现出显着增强的催化OER性能，在10 mA cm ^-2时的OER过电势低至0.35 V，Tafel斜率仅为约40 mV dec ^-1。此外，在1.58 V vs. RHE的条件下，获得了令人印象深刻的比质量和面积电流密度，分别为17.5 A g ^-1和0.106 A m ^-2，分别比无缺陷对应物高约23倍和约36倍。 。