Despite being considered as efficient non‐noble metal‐based electrocatalysts for alkaline oxygen evolution reaction (OER), NiFe (oxy)hydroxides (NiFeOxHy) typically fall short of meeting practical requirements. To address this challenge, herein, we introduce a facile in situ electrochemical incorporation technique to form Sn‐doped NiFe‐layered double hydroxide (NiFeSn‐LDH) precatalysts. Subsequently, under the alkaline OER process, the precatalyst evolves into stannate ion‐adsorbed NiFe oxyhydroxides (NiFeOOH). The presence of these stable stannate oxyanions plays a key role in mitigating Fe leaching, optimizing the electronic structure of NiFeOOH, and improving its reaction kinetics, thereby significantly enhancing alkaline OER performance. Notably, the nickel foam‐supported NiFeSn‐LDH demonstrated impressive results delivering a large current density of 100 mA cm−2 at an overpotential as low as ~260 mV and maintaining the industrial‐relevant ~500 mA cm−2 current density over 5 days with negligible activity decay, surpassing the performance of most of the transition metal‐based electrocatalysts. Comprehensive advanced characterization of the precatalysts, before and after the OER reactions, has been performed to uncover stable residual stannate ions at the surface of NiFeOxHy and to determine their pivotal role in promoting alkaline OER.

中文翻译：

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通过含 Sn 阴离子对 NiFe 羟基氧化物的调节实现高效碱性水氧化电催化

尽管NiFe（羟基）氢氧化物（NiFeOxHy）被认为是用于碱性析氧反应（OER）的有效非贵金属电催化剂，但通常无法满足实际要求。为了应对这一挑战，我们引入了一种简便的原位电化学掺入技术来形成 Sn 掺杂 NiFe 层状双氢氧化物 (NiFeSn-LDH) 预催化剂。随后，在碱性 OER 过程中，预催化剂演变为锡酸根离子吸附的 NiFe 羟基氧化物 (NiFeOOH)。这些稳定的锡酸氧阴离子的存在在减少 Fe 浸出、优化 NiFeOOH 的电子结构和改善其反应动力学方面发挥着关键作用，从而显着提高碱性 OER 性能。值得注意的是，泡沫镍支撑的 NiFeSn-LDH 表现出令人印象深刻的结果，在低至 ~260 mV 的过电势下提供 100 mA cm−2 的大电流密度，并在 5 天内保持工业相关的 ~500 mA cm−2 电流密度活性衰减可以忽略不计，超过了大多数过渡金属基电催化剂的性能。对 OER 反应前后的预催化剂进行了全面的高级表征，以揭示 NiFeOxHy 表面稳定的残留锡酸根离子，并确定它们在促进碱性 OER 中的关键作用。