The low-cost transition metal oxides have drawn widespread interest as alternatives to noble metal-based electrocatalysts for oxygen evolution reaction (OER). Transition metal oxides usually undergo surface reconstruction during electrochemical reaction to form the actual active species. However, in-depth understanding and regulating of the surface reconstruction of active phases for oxides in OER remains an onerous challenge. Herein, we report a simple Fe element substitution strategy to facilitate the surface reconstruction of spinel oxide NiCr₂O₄ to generate active (oxy)hydroxides. The activated Fe-doped NiCr₂O₄ (Act-Fe-NCO) exhibits a lower OER overpotential of 259 mV at 10 mA cm⁻² than activated NiCr₂O₄ (Act-NCO, 428 mV), and shows excellent stability for 120 h. The electrochemically activated CV measurement and nanostructure characterizations reveal that Fe substitution could promote the consumption of lattice oxygen during electrochemical activation to induce the leaching of soluble Cr cations, thereby facilitating the reconstruction of remaining Ni cations on the surface into (oxy)hydroxide active species. Moreover, theoretical calculations further demonstrate that the O 2p band center of NiCr₂O₄ moves towards the Fermi level due to Fe substitution, thus promoting lattice oxygen oxidation and providing greater structural flexibility for surface reconstruction. This work shows a promising way to regulate the surface reconstruction kinetics and OER electrocatalytic activity of transition metal oxides.

低成本过渡金属氧化物作为析氧反应（OER）贵金属电催化剂的替代品引起了广泛的兴趣。过渡金属氧化物通常在电化学反应过程中经历表面重构以形成实际的活性物质。然而，深入理解和调控 OER 中氧化物活性相的表面重构仍然是一个艰巨的挑战。在此，我们报告了一种简单的 Fe 元素替代策略，以促进尖晶石氧化物 NiCr ₂ O ₄的表面重构，以生成活性（氧）氢氧化物。活化的Fe掺杂NiCr ₂ O ₄ (Act-Fe-NCO)在10 mA cm ^-2下表现出比活化的NiCr ₂ O ₄ (Act-NCO, 428 mV)更低的OER过电位259 mV，并且表现出优异的稳定性。 120 小时。电化学活化的CV测量和纳米结构表征表明，Fe取代可以促进电化学活化过程中晶格氧的消耗，从而诱导可溶性Cr阳离子的浸出，从而促进表面上剩余的Ni阳离子重构为（羟基）氢氧化物活性物种。此外，理论计算进一步表明，由于Fe取代，NiCr ₂ O ₄的O 2p 能带中心向费米能级移动，从而促进晶格氧氧化，为表面重构提供更大的结构灵活性。这项工作展示了一种调节过渡金属氧化物表面重构动力学和 OER 电催化活性的有前景的方法。