催化学报 ›› 2024, Vol. 62: 209-218.DOI: 10.1016/S1872-2067(24)60046-X

• 论文 • 上一篇    下一篇

富含氧空位的由多金属氧簇辅助的银基异质结用于高效电催化固氮

陈昕煜a,1, 赵聪聪a,1, 任静b, 李波a, 刘倩倩a, 李葳a, 杨帆a, 陆思琦a, 赵宇飞b,c, 颜力楷a,*(), 臧宏瑛a,*()   

  1. a东北师范大学化学学院, 功能材料化学研究所, 纳米生物传感分析吉林省高等学校重点实验室, 多酸与网格材料化学教育部重点实验室, 吉林长春 130024
    b北京化工大学, 化工资源有效利用国家重点实验室, 北京 100029
    c衢州资源化工创新研究院, 浙江衢州 323000
  • 收稿日期:2024-03-06 接受日期:2024-04-19 出版日期:2024-07-18 发布日期:2024-07-10
  • 通讯作者: 电子信箱: yanlk924@nenu.edu.cn (颜力楷), zanghy100@nenu.edu.cn (臧宏瑛).
  • 作者简介:1共同第一作者.
  • 基金资助:
    国家自然科学基金(22322102);国家自然科学基金(21871042);国家自然科学基金(21471028);中央高校基本科研业务费-优秀青年团队项目(2412023YQ001);吉林省自然科学基金(20200201083JC);吉林省教育厅自然科学基金(JJKH20201169KJ);中国科学院长春应用化学研究所高分子物理与化学国家重点实验室开放研究基金(2023-16)

An oxygen-vacancy-rich polyoxometalate-aided Ag-based heterojunction electrocatalyst for nitrogen fixation

Xinyu Chena,1, Cong-Cong Zhaoa,1, Jing Renb, Bo Lia, Qianqian Liua, Wei Lia, Fan Yanga, Siqi Lua, YuFei Zhaob,c, Li-Kai Yana,*(), Hong-Ying Zanga,*()   

  1. aKey Laboratory of Polyoxometalate and Reticular Meterial Chemistry of Ministry of Education, Key Laboratory of Nanobiosensing and Nanobioanalysis at Universities of Jilin Province, Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin, China
    bState Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
    cQuzhou Institute for Innovation in Resource Chemical Engineering, Quzhou 323000, Zhejiang, China
  • Received:2024-03-06 Accepted:2024-04-19 Online:2024-07-18 Published:2024-07-10
  • Contact: E-mail: yanlk924@nenu.edu.cn (L.-K. Yan), zanghy100@nenu.edu.cn (H.-Y. Zang).
  • About author:1 Contributed equally to this work.
  • Supported by:
    National Natural Science Foundation of China(22322102);National Natural Science Foundation of China(21871042);National Natural Science Foundation of China(21471028);Fundamental Research Funds for the Central Universities-Excellent Youth Team Program(2412023YQ001);Natural Science Foundation of Jilin Province(20200201083JC);Natural Science Foundation of the Department of Education of Jilin Province(JJKH20201169KJ);Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, the Chinese Academy of Sciences(2023-16)

摘要:

目前, 工业产氨主要依赖传统的Haber-Bosch工艺, 然而该工艺条件苛刻, 需要高温(350‒550 °C)和高压(150‒250 bar), 每年消耗全球能源供应的2%, 同时排放4.5亿吨二氧化碳(占全球总排放量的1.6%). 近年来, 科研工作者致力于开发高效率、高选择性的固氮电催化剂, 但是由于析氢反应的强烈竞争, 目前已报道的氮还原催化剂仍然受到低法拉第效率和低氨产率的限制. 因此, 开发活性位点丰富、氮气吸附能力强、催化性能优异的氮还原电催化剂成为当务之急. 贵金属催化剂由于其纳米结构中富含活性位点, 并且金属表界面处具有较好的导电性, 因此表现出较高的法拉第效率. 而分子催化剂因可调的电子结构和明确的构效关系引起了广泛关注. 多金属氧簇是一种典型的金属聚阴离子团簇, 由氧原子连接的含氧多面体组成, 且具备优异的氧化还原性能. 因此, 本课题组尝试将多金属氧簇分子引入到氮还原催化剂中, 并探究其催化机理.

本文选取了一个多金属氧簇为前驱体, 在溶剂、还原剂和诱导剂共存时, 通过一锅法合成了富含氧空位的AgPW11/Ag纳米方块电催化剂. 实验结果表明, 富含氧空位的AgPW11/Ag异质结催化剂在-0.2 V (vs. RHE)电位时表现出高达46.02±1.03 μg h‒1 mg‒1cat.的氨产率和34.07±0.16%的法拉第效率, 催化反应能够稳定运行32 h且性能未见衰减, 显著优于银催化剂. 随后系统地研究了AgPW11/Ag催化剂的氮还原活性位点, 发现异质结中的银单质为催化反应提供了高导电性的支持, 而催化剂中的银氧簇具有较好的电子得失能力, 有利于促进氮还原反应中的六电子转移过程. 丰富的氧空位利于吸附氮气, 也能协同提升AgPW11/Ag对电化学氮还原的催化活性. 密度泛函理论计算结果表明, 在还原后的银氧簇中, 银原子d轨道与氮气π*轨道之间的强相互作用激活了吸附的氮气, 促进了第一个质子化过程: *N2向*N-NH 的转化(电化学决速步).

综上, 本工作建立了异质结催化剂的催化性能与其分子结构之间的构效关系, 为开发多金属氧簇及其衍生物作为电催化剂提供了依据和思路.

关键词: 多酸, 金属氧簇, 电催化, 氮还原, 氧空位, 密度泛函理论, 异质结

Abstract:

Polyoxometalates (POMs) with well-defined molecular structures are sustainable and promising catalysts for reducing nitrogen to ammonia under ambient conditions. In this study, oxygen-vacancy-rich AgPW11/Ag nanocube catalysts were synthesized via a one-pot method using POMs, reductants, and inducers. The oxygen-vacancy-rich AgPW11/Ag heterojunction catalyst exhibited a significant ammonia yield as high as 46.02 ± 1.03 μg h-1 mg-1cat. and faradaic efficiency of 34.07 ± 0.16% at a potential of -0.2 V (vs. RHE), maintaining stable catalysis for 32 h without decay and greatly outperforming the Ag catalyst. The excellent catalytic performance and mechanism were established using density functional theory calculations. The robust interaction between the d orbitals of the Ag atom in AgPW1112e and π* orbitals of N2 activates the adsorbed N2 and promotes the conversion of the first protonation process *N2 to *N-NH (the potential determination step). This study provides a new avenue for designing stable Ag-based catalysts for nitrogen fixation.

Key words: Polyoxometalates, Metal-oxo cluster, Electrocatalysis, Nitrogen reduction, Oxygen vacancy, Density functional theory, Heterojunction