Abstract

NiFe-based electrocatalysts will experience dynamical surface reconstruction during oxygen evolution reaction (OER) process, and the derived metal (oxy)hydroxide hybrids on the surface have been considered as the actual active species for OER. Tremendous efforts have been dedicated to understanding the surface reconstruction, but there is rare research on recognizing the origin of improved performance derived from anion species of substrate. Herein, the OER electrocatalytic characteristics were tuned with different anions in NiFe-based catalyst, using NiFe-based oxides/nitride/sulfide/selenides/phosphides (NiFeX, X = O, N, S, Se, and P) as the model materials. The combination of X-ray photoelectronic spectroscopy, electrochemical tests, operando spectroscopic characterizations, and density functional theory (DFT) calculations, reveals that anion with lower electronegativity in NiFe-based catalyst leads to higher conductivity and delayed valence transition of Ni sites, as well as optimized adsorption behavior towards oxygen intermediates, contributing to enhanced OER performance. Accordingly, NiFeP electrocatalyst demonstrates an ultralow overpotential of 265 mV at 20 mA·cm⁻² for OER, as well as long-term stability. This work not only offers further insights into the effect of anionic electronegativity on the intrinsic OER electrocatalytic properties of NiFe-based electrocatalyst but also provides guide to design efficient non-noble metal-based electrocatalysts for water oxidation.

中文翻译：

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通过 Ni−Fe−X（X = O、S、Se、N 和 P）电催化剂中的阴离子调节来调节氧化还原转变动力学，实现高效水氧化

摘要

NiFe基电催化剂在析氧反应（OER）过程中会经历动态表面重构，表面衍生的金属（羟基）氢氧化物杂化物被认为是OER的实际活性物质。人们付出了巨大的努力来理解表面重构，但很少有研究认识到源自基材阴离子种类的性能改进的根源。在此，使用 NiFe 基氧化物/氮化物/硫化物/硒化物/磷化物（NiFeX，X = O、N、S、Se 和 P）作为模型材料，通过 NiFe 基催化剂中的不同阴离子调节 OER 电催化特性。 X射线光电子能谱、电化学测试、操作光谱表征和密度泛函理论（DFT）计算的结合表明，NiFe基催化剂中电负性较低的阴离子会导致更高的电导率和延迟的Ni位点价态跃迁。对氧中间体的优化吸附行为，有助于提高 OER 性能。因此，NiFeP电催化剂在20 mA·cm ^-2下表现出265 mV的超低OER过电势以及长期稳定性。这项工作不仅进一步深入了解阴离子电负性对 NiFe 基电催化剂固有 OER 电催化性能的影响，而且还为设计用于水氧化的高效非贵金属基电催化剂提供了指导。