Designing earth-abundant electrocatalysts that are highly active, low-cost, and stable for the oxygen evolution reaction (OER) is crucial for electrochemical water splitting. However, in conventional electrode fabrication strategies, NiFe layered double hydroxide (NiFe LDH) catalysts are usually coated onto substrates as external components, which suffers from poor conductivity, easily detaches from the substrate, and hinders their long-term utilization. Herein, the surface-reconstruction strategy is used to synthesize in situ autologous NiFe LDH to increase the surficial active sites numbers. The FeNi foam (FNF) serves as both the metal source and substrate, and the obtained NiFe LDH nanosheets (NSs) are firmly anchored in the monolithic FNF. What needs to be emphasized is that the strategy does not involve any high-temperature or high-pressure processes, apart from a cost-effective etching and a specified drying treatment. The nanostructure of NiFe LDH and the synergistic effect between Fe and Ni simultaneously lead to an enhanced catalytic effect for the OER. Remarkably, the sr-FNF46 requires only an ultralow overpotential of 283 mV to achieve a current density of 100 mA cm^–2 for the OER in 1 M KOH electrolyte, and exhibits excellent stability. Thus, the obtained electrode holds promise for electrocatalytic applications. Finally, the formation mechanism of NiFe LDH NSs due to surface reconstruction is investigated and discussed in detail.

中文翻译：

---

用于高效析氧的 FeNi 泡沫基板的表面重建

设计对析氧反应 (OER) 具有高活性、低成本和稳定性的地球丰富的电催化剂对于电化学水分解至关重要。然而，在传统的电极制造策略中，NiFe层状双氢氧化物（NiFe LDH）催化剂通常作为外部组件涂覆在基底上，其导电性差，容易与基底分离，阻碍了它们的长期利用。在此，表面重建策略用于原位合成自体 NiFe LDH，以增加表面活性位点数量。FeNi 泡沫 (FNF) 作为金属源和基底，所获得的 NiFe LDH 纳米片 (NSs) 牢固地固定在整体 FNF 中。需要强调的是，该策略除了具有成本效益的蚀刻和特定的干燥处理外，不涉及任何高温或高压过程。NiFe LDH 的纳米结构和 Fe 和 Ni 之间的协同作用同时导致对 OER 的催化作用增强。值得注意的是，sr -FNF46 仅需要 283 mV 的超低过电位即可在 1 M KOH 电解质中实现 100 mA cm ^{–2的电流密度，并表现出出色的稳定性。}因此，所获得的电极有望用于电催化应用。最后，详细研究和讨论了由于表面重构导致的 NiFe LDH NSs 的形成机制。