High-valence Ni and Fe metal sites have demonstrated a crucial role in enhancing the catalytic performances of NiFe-LDH electrocatalysts in oxygen evolution reaction (OER). Although considerable OER catalytic performances achieved under high overpotential, the catalytic talent of NiFe-LDH electrocatalysts at low overpotential is rarely realized due to the absence of high-valence Ni and Fe sites. We herein report a surface engineering route to fabricate sulfated NiFe-LDH nanosheets via ion exchange strategy in sulfate-rich media. XPS results reveal a modified surface electronic structure with high-valence Ni and Fe after ion exchange reaction. Computational PDOS results suggest that computed d-band centers (ε_d) of Fe and Ni for sulfated NiFe-LDH show a significant downward shift resulting an increased valence of metal cation with orbital volume shrinkage. The high-valence Fe can facilitate a optimized multi-electron process of Ni center from [Ni^II-OH]⁻/[Ni^III-OH]⁻ to Ni^IV-OOH rather than Ni^II/Ni^III to Ni^IV at low overpotential. The high-valence Ni can serve as the highly active center for O-O coupling during OER process. Combined with the synergetic action of high-valence Fe and Ni, the sulfated NiFe-LDH nanosheets exhibit much larger reaction kinetics and outstanding electrocatalytic activity on glassy carbon electrode (η₁₀ = 219 mV, η₅₀ = 288 mV) with a remarkable long-term stability.

高价 Ni 和 Fe 金属位点在提高 NiFe-LDH 电催化剂在析氧反应 (OER) 中的催化性能方面发挥着至关重要的作用。尽管在高过电位下实现了可观的 OER 催化性能，但由于缺乏高价 Ni 和 Fe 位点，NiFe-LDH 电催化剂在低过电位下的催化能力很少实现。我们在此报告了一种在富含硫酸盐的介质中通过离子交换策略制造硫酸化 NiFe-LDH 纳米片的表面工程途径。XPS 结果揭示了离子交换反应后具有高价 Ni 和 Fe 的改性表面电子结构。计算 PDOS 结果表明计算的 d 波段中心 (ε _d) 硫酸化 NiFe-LDH 的 Fe 和 Ni 显示出显着的向下移动，导致金属阳离子的化合价增加，轨道体积收缩。在低过电位下，高价 Fe 可以促进 Ni 中心从 [Ni ^II -OH] ^- /[Ni ^III -OH] ^-到 Ni ^IV -OOH 而不是 Ni ^II /Ni ^III到 Ni ^IV的优化多电子过程. 高价镍可以作为 OER 过程中 OO 耦合的高活性中心。结合高价 Fe 和 Ni 的协同作用，硫酸化的 NiFe-LDH 纳米片在玻碳电极上表现出更大的反应动力学和出色的电催化活性（η₁₀ = 219 mV, η ₅₀ = 288 mV) 具有显着的长期稳定性。