催化学报 ›› 2026, Vol. 81: 148-158.DOI: 10.1016/S1872-2067(25)64842-X

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定量视角: 基于恒电位微动力学模拟探究电位依赖性(电)化学步骤在电催化合成氨中的关键作用

吕兴帅a(), 赵佩b, 梁岩b, Thomas Frauenheimc, 寇良志d()   

  1. a 中国海洋大学化学化工学院, 山东青岛 266100, 中国
    b 中国海洋大学信息科学与工程学部, 山东青岛 266100, 中国
    c 雅各布斯大学自然科学学院, 不莱梅, 德国
    d 成都大学高等研究院, 四川成都 610106, 中国
    e 昆士兰科技大学机械、医疗与过程工程学院, 布里斯班, 澳大利亚
  • 收稿日期:2025-06-24 接受日期:2025-08-13 出版日期:2026-02-18 发布日期:2025-12-26
  • 通讯作者: *电子信箱: lvxs@ouc.edu.cn (吕兴帅),Liangzhi.kou@qut.edu.cn (寇良志).
  • 基金资助:
    山东省泰山学者项目(tsqn202507090);国家资助博士后研究人员计划(GZB20250022);山东省自然科学基金(ZR2023QA058);山东省自然科学基金(ZR2023QA070);山东省自然科学基金(ZR2025QC1086);中国海洋大学青年英才项目

Quantitative insights into the critical role of potential-dependent (electro)chemical steps in ammonia electrosynthesis via constant-potential microkinetic simulations

Xingshuai Lva(), Pei Zhaob, Yan Liangb, Thomas Frauenheimc, Liangzhi Koud()   

  1. a College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, Shandong, China
    b Department of Physics, College of Information Science and Engineering, Ocean University of China, Qingdao 266100, Shandong, China
    c School of Science, Constructor University, Bremen 28759, Germany
    d Institute for Advanced Study, Chengdu University, Chengdu 610106, Sichuan, China
    e School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, Queensland 4001, Australia
  • Received:2025-06-24 Accepted:2025-08-13 Online:2026-02-18 Published:2025-12-26
  • Contact: *E-mail: lvxs@ouc.edu.cn (X. Lv),liangzhi.kou@qut.edu.au (L. Kou).
  • Supported by:
    Taishan Scholar Program of Shandong Province(tsqn202507090);Postdoctoral Fellowship Program of CPSF(GZB20250022);Natural Science Foundation of Shandong Province(ZR2023QA058);Natural Science Foundation of Shandong Province(ZR2023QA070);Natural Science Foundation of Shandong Province(ZR2025QC1086);Young Talents Project at Ocean University of China

摘要:

电化学氮还原反应(eNRR)已成为替代高能耗哈伯-博施法的可持续方案, 可在环境条件下实现分布式氨(NH3)生产, 同时显著降低传统NH3合成过程中的碳排放. 尽管电化学合成氨技术研究日益增多, 但是该领域仍主要处于试错探索阶段. 由于反应过程复杂, NH3产率和选择性低下严重制约了该技术的发展. 更严峻的是, 即使在严格的操作规范下, 许多已报道体系仅能产生微量NH3, 甚至无法检测到NH3. 在此背景下, 亟需明确提升eNRR效率的可行路径. 关键突破口在于阐明实际工作条件下该还原反应的本质特性, 这对于构建更完善的eNRR化学理论体系及实现理论指导的催化剂设计具有决定性意义.

本文结合前沿的恒电势计算和微动力学方法, 定量探究了不同电位下eNRR过程中质子耦合电子转移等电化学步骤和氨脱附等化学步骤对合成氨活性的影响. 该方法能够显式监测电化学与非电化学步骤, 并定量预测电场对eNRR宏观性能的影响. 通过将溶剂化效应与外加电位下的电化学步骤和化学步骤相结合, 发现氢原子与氮气覆盖度的交叉现象是导致高电位下催化剂性能过早衰减的根本原因. 基于本模型成功复现了不同金属的理论活性趋势, 与实验结果相吻合. 本文进一步为eNRR催化剂筛选提出了一套新的理论方案, 其中理想催化剂应具备较宽电位区间内绝对优势的氮气吸附能力, 以确保在高电位下充分促进eNRR. 本研究并非旨在筛选对eNRR具有特殊活性的单原子催化剂, 而是着重指出在eNRR过程研究和电催化剂筛选中忽略化学步骤可能导致电催化活性预测的显著偏差. 证明必须在明确外加电位下同时考虑电化学步骤与化学步骤, 才能准确捕捉eNRR过程的热力学限制和宏观活性. 需要特别注意的是, 在较负电位下, *NH3解吸步骤, 尤其是第二步*NH3解吸过程会显著限制反应活性, 应在未来eNRR评估中予以充分考虑. 该步骤对NH3合成速率的影响可达数个数量级. 此外, 提升反应温度被证明是在低电位条件下增强NH3合成效率的有效策略.

综上, 本文建立了在实际反应条件下定量探究电催化过程的理论方案. 该研究方法和见解对涉及电化学-化学耦合步骤的其他电化学反应如氧还原、二氧化碳还原、硝酸盐还原及C-N耦合反应等具有更广泛的启示意义.

关键词: 电化学, 非电化学步骤, 恒电势计算, 电位依赖自由能, 微动力学模型

Abstract:

Electric fields play a pivotal role in renewable energy technologies and are essential for enabling a sustainable future. However, the regulation of macroscale catalytic behavior by electric fields has not been well digitally understood yet, as conventional computational models rely on reaction energy profiles that overlook the nonlinear effects of electric fields on elementary reaction steps. Here, we use advanced constant-potential microkinetic simulations to revisit the electrochemical nitrogen reduction reaction (eNRR) under operating conditions, which makes it possible to explicitly integrate both electrochemical and chemical steps and quantitatively predict the effects of electric fields on eNRR macroscale performance. The theoretical activity trends for different metals were successfully reproduced with our model, which are in good qualitative agreement with experimental observations. Furthermore, we propose a new theoretical protocol for eNRR catalyst screening, where an optimal catalyst should exhibit overwhelming N2 adsorption ability over a wide potential range to sufficiently facilitate eNRR at high potentials. Interestingly, the rate-determining step undergoes dynamic evolution with potential variations, with chemical steps imposing fundamental constraints on practical ammonia (NH₃) electrosynthesis. Microkinetic simulations demonstrate that incorporating *NH₃ desorption steps can alter reaction rates by orders of magnitude, highlighting their critical yet often overlooked role. This work establishes a quantitative framework for achieving accurate, physically realistic theoretical simulations in heterogeneous electrochemistry.

Key words: Electrochemistry, Non-electrochemical steps, Constant potential model, Potential-dependent free energy, Microkinetic modeling