催化学报 ›› 2025, Vol. 74: 240-249.DOI: 10.1016/S1872-2067(24)60283-4

• 论文 • 上一篇    下一篇

单原子钌诱导界面水结构调控实现高效的碱性氢氧化反应

靳一鸣1, 成文静1, 罗威*()   

  1. 武汉大学化学与分子科学学院, 湖北武汉 430072
  • 收稿日期:2025-01-17 接受日期:2025-02-21 出版日期:2025-07-18 发布日期:2025-07-20
  • 通讯作者: *电子信箱: wluo@whu.edu.cn (罗威).
  • 作者简介:1共同第一作者.
  • 基金资助:
    国家重点研发计划(2021YFB4001200);国家自然科学基金(22272121);国家自然科学基金(21972107)

Ru single atoms-induced interfacial water structure regulation for efficient alkaline hydrogen oxidation reaction

Yiming Jin1, Wenjing Cheng1, Wei Luo*()   

  1. College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, Hubei, China
  • Received:2025-01-17 Accepted:2025-02-21 Online:2025-07-18 Published:2025-07-20
  • Contact: *E-mail: wluo@whu.edu.cn (W. Luo).
  • About author:1Contributed equally to this work.
  • Supported by:
    National Key Research and Development program of China(2021YFB4001200);National Natural Science Foundation of China(22272121);National Natural Science Foundation of China(21972107)

摘要:

合理设计催化剂的几何与电子结构以提高催化位点的本征活性是电催化领域的关键之一. 具有单位点分散结构的单原子催化剂表现出较高的原子利用率及催化效率, 特别是与金属团簇/纳米颗粒耦合时, 其可为涉及不同反应中间体的复杂过程提供多元活性位点, 从而显著提升各种电催化过程的反应性能. 然而, 目前对于单原子与金属团簇/纳米颗粒协同效应的探究仍局限于催化剂电子结构及反应中间体热力学吸附能的调控上, 而忽视了优化电化学界面, 特别是改善双电层环境中的界面水结构及氢键相互作用对于电催化反应动力学的重要影响.

因此为了深入探究单原子位点的催化作用, 本文利用多孔氮掺杂碳的限域锚定效应, 以及简易的浸渍煅烧还原法制备了氮碳负载的钌单原子及纳米颗粒耦合催化剂(记为Ru1,n/NC), 并选择碱性氢氧化反应(HOR)作为研究模型以阐明两者间的协同效应. 透射电子显微镜及高角环形暗场-扫描透射显微镜表征表明, 平均粒径约为1.8 nm的Ru纳米颗粒均匀分散在氮碳载体上, 并且其周围可观测到明显的Ru单原子, 证明耦合催化剂Ru1,n/NC的成功制备. X射线光电子能谱及吸收谱表征表明高价态Ru单原子的存在及由Ru向氮碳基底的电荷转移过程, 同时扩展X射线吸收精细结构表明, Ru1,n/NC中主要存在Ru-Ru及Ru-N配位环境. 电化学测试表明, Ru1,n/NC在0.1 mol L-1 KOH溶液中的HOR性能显著超越单一的Ru纳米颗粒对照样品, 并且与目前最为先进的商业铂碳催化剂相当, 其面积及质量比活性分别达到0.43 mA cmPGM-2及1.15 mA μgPGM-1, 与Ru纳米颗粒相比提升了两倍之多. 密度泛函理论计算结果发现, Ru单原子及纳米颗粒耦合结构的设计调控了Ru的d带中心位置及其吸附水后的反键轨道填充度, 从而优化了其氢及水结合能. 并且Ru1,n/NC表面吸附的水分子可利用氢键作用促进OH-向电极表面的转移, 以便其与相邻的吸附氢中间体结合完成HOR过程. 随后利用表面增强原位红外光谱探究了界面水结构在HOR电势下的动态演变过程. Ru1,n/NC得益于带正电荷Ru单原子的存在, 可以稳定强氢键水分子中带有负电荷的氧端, 因而在任意电势下均具有最高的强氢键水占比, 表明氢键网络联通性最为优异, 可以加速碱性HOR中的质子耦合电子转移动力学, 从而促进溶液中OH-物种通过Grotthuss机制向电极表面的传输速率, 最终显著提升了Ru基材料的碱性氢电催化能力.

综上所述, 本文成功制备了具有高本征活性及原子利用率的钌单原子及纳米颗粒耦合催化剂, 并揭示了钌单原子对于界面双电层中的水分子及氢键网络结构的调控作用, 最终揭示了其碱性HOR性能提升的本质原因, 为单原子催化剂的合理设计拓宽思路.

关键词: 双电层环境, 氢氧化反应, 界面水结构, 物质传输过程, 单原子位点

Abstract:

The employment of single atom catalysts (SACs) remarkably increases atomic utilization and catalytic efficiency in various electrochemical processes, especially when coupled with metal clusters/nanoparticles. However, the synergistic effects mainly focus on the energetics of key intermediates during the electrocatalysis, while the properties of electrode surface and electric-double-layer (EDL) structure are largely overlooked. Herein, we report the synthesis of Ru nanoparticles integrated with neighboring Ru single atoms on nitrogen doped carbon (Ru1,n/NC) as efficient catalysts toward hydrogen oxidation reaction (HOR) under alkaline electrolytes. Electrochemical data, in situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy, and density functional theory calculations reveal that the positively charged Ru single atoms could lead to the dynamically regulated proportion of strongly hydrogen-bonded interfacial water structure with O-down conformation and optimized connectivity of the hydrogen-bond network in the EDL region, which contribute to the accelerated diffusion of hydroxide ions to the electrified interfaces. Consequently, the obtained Ru1,n/NC catalyst displays remarkable HOR performance with the mass activity of 1.15 mA μgPGM-1 under alkaline electrolyte. This work demonstrates the promise of single atoms for interfacial water environment adjustment and mass transfer process modulation, providing new insights into rational design of highly-effective SAC-based electrocatalysts.

Key words: Electric double layer, Hydrogen oxidation reaction, Interfacial water structure, Mass transfer process, Single atoms