物理化学学报

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Ni掺杂FeS2中双向电子效应平衡氧结合能促进氧析出反应

杨甫林1, 和润泽2, Sneha Mittal3, 王书莉2, Anantharaj Sengeni3, 冯立纲1,2   

  1. 1 昆明理工大学材料科学与工程学院，云南 昆明 650093;
    2 扬州大学化学与材料学院，江苏 扬州 225002;
    3 Laboratory for Electrocatalysis and Energy, Department of Chemistry, Indian Institute of Technology, Kanpur 208016, Uttar Pradesh, India
  • 收稿日期:2026-06-04 修回日期:2026-07-12 录用日期:2026-08-26
  • 通讯作者: 冯立纲Ligang Feng E-mail:fenglg11@gmail.com, ligang.feng@kust.edu.cn
  • 基金资助:
    作者感谢国家自然科学基金(22272148)以及云南省基础研究计划项目(202601BE070001-014)的资助

Balancing oxygen binding via bidirectional electronic effects in Ni-doped FeS2 for oxygen evolution reaction catalysis

Fulin Yang1, Runze He2, Sneha Mittal3, Shuli Wang2, Anantharaj Sengeni3, Ligang Feng1,2   

  1. 1 Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan Province, China;
    2 School of Chemistry and Materials, Yangzhou University, Yangzhou 225002, Jiangsu Province, China;
    3 Laboratory for Electrocatalysis and Energy, Department of Chemistry, Indian Institute of Technology, Kanpur 208016, Uttar Pradesh, India
  • Received:2026-06-04 Revised:2026-07-12 Accepted:2026-08-26

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摘要： 铁基氧析出反应(OER)催化剂尽管具有良好的理论预测性能以及低成本优势，但其发展仍落后于镍基催化剂。深入理解催化机理对于推进铁基催化剂的发展十分必要。目前，铁基非金属化合物如硫化物、磷化物、硒化物等，因其电子结构可调和导电性相对较高，已被广泛作为高活性OER预催化剂。然而，在OER条件下，这类预催化剂通常会发生表面重构生成羟基氧化物，使得真正的活性物种与其初始结构大不相同，进而使得构效关系的确立变得复杂化。本文以镍掺杂的FeS2纳米球催化剂为研究对象，揭示了表面重构后催化剂中存在的双向电子效应，阐明了残余FeS2内核以及镍掺杂原子在优化催化性能中的关键作用。结构表征证实了镍杂原子成功掺杂到了黄铁矿型FeS2的晶格中。硫化物纳米球表面包覆有一层无定形碳层，有助于提高电荷转移效率并在电催化过程中维持催化剂结构的完整性。电化学测试结果表明，所制备的催化剂(Ni0.2-FeS2@C)在碱性电解液中表现出显著增强的OER活性，仅需270 mV的过电位即可驱动10 mA cm−2的电流密度，优于未掺杂以及未包覆的对比样品(FeS2@C和FeS2)。此外，Ni0.2-FeS2@C在5000次伏安循环后活性几乎无衰减，并在100 h的恒电位运行中保持稳定，且氧气生成的法拉第效率接近100%，展现出良好的耐久性和选择性。光谱分析和密度泛函理论计算表明，OER过程中发生的表面重构会如文献报道的那样形成羟基氧化物，但其中存在此前未被观察到的独特电子相互作用。一方面，残余的FeS2内核使表面羟基氧化物的d带中心上移，增强了对关键含氧中间体的吸附能力；另一方面，镍掺杂又引起d带中心下移，从而反向削弱了过强的吸附行为。这种双向调控优化了活性位点的电子结构，有效平衡了OER中间体的吸附强度，进而降低了电催化反应能垒。因此，本工作不仅为铁基OER催化剂的理性设计提供了一种可行的策略，也深化了对真实活性相中平衡电子调制增强电催化活性这一机理的认识。

关键词: 氧析出反应, 双向电子效应, 表面重构, d带中心, 掺杂效应

Abstract: The advancement of Fe-based oxygen evolution reaction (OER) catalysts lags behind their Ni-based counterparts, albeit their good theoretically predicted performance and low cost. Deeply understanding the catalytic mechanism would be necessary to advance the Fe-based catalysts. Currently, Fe-based non-metallic compounds, such as sulfides, phosphides, and selenides, have been widely explored as highly active OER precatalysts because of their tunable electronic structures and relatively high electrical conductivity. Nevertheless, these precatalysts usually undergo surface reconstruction into oxyhydroxides under OER conditions, making the real active phase different from the pristine compound and complicating the structure-performance relationship. Herein, taking the Ni-doped FeS2 nanosphere catalyst as a platform, we discover a nuanced bidirectional electronic effect within the surface-reconstructed active phase, showcasing the vital roles of both residual FeS2 and Ni dopants in optimizing catalytic performance. Structural characterizations confirm the successful incorporation of Ni dopants into the pyrite FeS2 lattice. An amorphous carbon layer is coated on the sulphide nanospheres, which contributes to improving charge transfer efficiency and maintaining structural integrity during electrocatalysis. As a result, the obtained catalyst, typically denoted as Ni0.2-FeS2@C, achieves markedly enhanced OER activity in the alkaline electrolyte, requiring an overpotential of only 270 mV to reach 10 mA cm−2, much lower than those of the undoped and uncoated counterparts (FeS2@C and FeS2). Moreover, Ni0.2-FeS2@C exhibits negligible activity decay after 5000 cyclic voltammetry cycles and remains stable during 100 h of constant-potential operation, with Faradaic efficiency for oxygen production close to 100%, demonstrating good catalytic durability and selectivity. Spectroscopic analyses and density functional theory calculations reveal that surface reconstruction during OER leads to the formation of oxyhydroxide as reported elsewhere, but unique electronic interactions, which have not been observed earlier. On the one hand, the residual FeS2 substrate upshifts the d-band center of the surface oxyhydroxide, strengthening the adsorption behavior of the crucial oxygenated intermediate. On the other hand, Ni dopants induce a downshift of the d-band center, which weakens over-binding inversely. The resulting bidirectional modulation optimizes the electronic structure of active sites and effectively balances the adsorption strength of OER intermediates, thereby reducing the OER energy barrier. Consequently, this work not only provides a viable strategy for the rational design of Fe-based OER catalysts but also deepens the mechanistic understanding of the real active phase of balanced electronic modulation in enhancing electrocatalytic activity.

Key words: Oxygen evolution reaction, Bidirectional electronic effect, Surface reconstruction, d-band center, Doping effect