催化学报 ›› 2023, Vol. 48: 32-65.DOI: 10.1016/S1872-2067(23)64429-8

• 综述 • 上一篇    下一篇

铜基催化剂电催化高效还原CO2制备C2+产物的调控策略

杨焕焕a, 李诗颖b, 许群a,c,*()   

  1. a郑州大学河南先进技术研究院, 河南郑州450001
    b中国科学院山西煤炭化学研究所煤转化国家重点实验室, 山西太原030001
    c郑州大学材料科学与工程学院, 河南郑州450001
  • 收稿日期:2022-12-04 接受日期:2023-02-28 出版日期:2023-05-18 发布日期:2023-04-20
  • 通讯作者: * 电子信箱: qunxu@zzu.edu.cn (许群).
  • 基金资助:
    国家自然科学基金(21773216);国家自然科学基金(U2004208);国家自然科学基金(51173170);中国博士后科学基金(2022TQ0351);河南省博士后科研基金(202002011);河南省高等学校重点科研项目(22A150024);郑州大学青年人才创新团队支持计划

Efficient strategies for promoting the electrochemical reduction of CO2 to C2+ products over Cu-based catalysts

Huanhuan Yanga, Shiying Lib, Qun Xua,c,*()   

  1. aHenan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450001, Henan, China
    bState Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, Shanxi, China
    cCollege of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450001, Henan, China
  • Received:2022-12-04 Accepted:2023-02-28 Online:2023-05-18 Published:2023-04-20
  • Contact: * E-mail: qunxu@zzu.edu.cn (Q. Xu).
  • About author:Qun Xu (Henan Institute of Advanced Technology, College of Materials Science and Engineering, Zhengzhou University) is an associate editor for Energy & Environmental Materials (Wiley). Prof. Qun Xu obtained her PhD in Physical Chemistry from the Institute of Chemistry, Chinese Academy of Science in 1999. In 2001, she finished her post doctor work in Karlsruhe Nuclear Center in Germany and return back to China. In recent years, she focuses on the design, synthesis and performance exploration of novel nanostructures. She has made outstanding contribution on the utilization of supercritical CO2 for the fabrication of advanced materials, and their relevant applications in energy storage and (photo)electrocatalysis. She has published more than 150 papers in top journals in the recent 10 years as corresponding author (h-index = 55 and 10670 citations), including Angew. Chem. Int. Ed., Adv. Mater., ACS Nano, Chem. Mater., and Adv. Funct. Mater., etc. Many papers were listed by ESI as the world’s top 1% highly cited papers and top 0.1% hot papers. She is one of the World Highly Cited Researchers in 2020, and World Top 2% Scientist (Stanford University).
  • Supported by:
    Natural Science Foundation of China(21773216);Natural Science Foundation of China(U2004208);Natural Science Foundation of China(51173170);China Postdoctoral Science Foundation(2022TQ0351);Henan Postdoctoral Foundation(202002011);Foundation of Henan Educational Committee(22A150024);Innovative Team Program of Zhengzhou University

摘要:

电催化CO2还原, 可利用太阳能、风能等可再生能源产生的清洁电能驱动CO2在常温常压下绿色高效地转化为甲烷, 甲醇、乙烯和乙醇等化学品. 其中, 多碳产物(C2+产物)因能量密度大、附加值高而备受关注. Cu可以有效吸附中间体CO, 促进C-C键偶联, 是目前公认的可以有效催化CO2转化为C2+还原产物的金属, 但反应涉及多电子转移、质子耦合、路径复杂,加之水相体系中析氢副反应的影响, C2+产物选择性差.
本文以CO2还原过程中的四个关键步骤为主线, 综述了Cu基催化剂表面结构的改性策略, 以提高CO2还原制备C2+产物性能, 并深入分析了催化剂表面结构与性能之间的构效关系. (1) 抑制析氢: 通过有机层修饰及形貌调控对催化剂表面进行疏水改性, 抑制H2O传输, 同时促进CO2扩散. (2) 促进CO2吸附活化: Cu与CO2捕获材料复合, 可以有效促进CO2吸附; 卤素离子可以提供孤对电子给CO2, 形成X-C键(X = F-, Cl-, Br-, I-), 促进CO2的吸附及活化. (3) 调控CO中间体的生成及吸附性能: Cu与CO高选择性催化剂复合构建双功能串联催化剂, 可以有效提高催化剂表面CO浓度及覆盖度; 催化剂表面增强的局部热-电场效应可促进CO中间体的吸附及耦合; 线性吸附的CO和桥式吸附的CO共存, 以及低频线性吸附的CO可以有效进行耦合, 促进C2+产物生成. (4) 促进C-C耦合成键: C-C耦合是生成C2+产物最关键的一步, 限域形貌结构, 可以有效提高中间产物在催化剂表面的浓度及保留时间, 提高C-C耦合几率; 氧化物衍生铜、杂原子掺杂和有机分子修饰等可以调控催化剂表面铜物种价态, Cuδ+和Cu0协同, 可以促进CO2活化, 增强CO中间体吸附, 降低C-C耦合能垒; 空位、晶界和台阶等缺陷可以改变C1中间体在催化剂表面的吸附性能, 降低C-C耦合能垒; Cu单原子催化剂较高的原子利用率以及Cu原子与配位原子协同可有效促进C-C耦合, 调节单一C2+产物选择性; 异质界面可以改变本征电导率, 提高电荷转移速率, 调节催化剂表面电子结构, 进一步调控对中间体的吸附, 促进C-C耦合几率. 催化剂表面结构重组、化学态变化、积碳、Fe/Ni等杂质沉积和微量有机杂质吸附等会影响催化反应稳定性. 构建Cu-载体相互作用及限域结构, 引入缺陷位点、原子掺杂、有机分子修饰和纯化电解质溶液等方法可以有效缓解催化剂失活.
此外, 本文指出了CO2还原制C2+产物领域未来潜在的研究方向: (1) 开发时间及空间分辨的原位谱学技术, 结合理论计算研究催化剂的动态变化及中间体的演变过程, 揭示催化反应机理, 为实现单一C2+产物高选择性, 设计高效率及高稳定性催化剂提供理论指导; (2) 深入认识催化反应失活机理, 设计新型催化剂及反应器, 提高整个体系反应稳定性; (3) 关注阳极反应, 尝试新的氧化反应替代能耗较高的析氧反应; 设计高稳定的阳极反应催化剂; 开发化学及机械稳定的离子交换膜, 减少CO2向阳极的扩散, 提高整体反应能效及经济性等.

关键词: 铜基催化剂, 二氧化碳电还原, 表面工程, C2+产物, 改性策略

Abstract:

Cu-based catalysts have been widely studied for the electrochemical CO2 reduction reaction (CO2RR) to yield high-value-added products with two or more carbons (C2+ products). The rational design of Cu-based catalysts is critical to improve the selectivity and energy efficiency of the CO2RR-to-C2+ process. Herein, we review recent advances in Cu-based catalysts with surface modification for four crucial factors in CO2RR-to-C2+ based on briefly analyzing the reaction mechanisms: (1) surface hydrophobization to inhibit the hydrogen evolution reaction; (2) introduction of CO2-capture materials, halide-ion doping, and Cuδ+/Cu0 synergy to promote CO2 adsorption and activation; (3) bifunctional catalysts and locally enhanced electric-thermal fields for modulating CO generation and adsorption; and (4) development of confinement structures and heterostructures, addition of oxidation states or defects, and use of single-atoms with different coordination environments to promote carbon-carbon coupling. In particular, the relationships between the surface properties of Cu-based catalysts and improved activity and C2+ selectivity in CO2RR are discussed, along with strategies for enhancing the stability of the catalyst. Furthermore, the current challenges and potential strategies for future CO2RR-to-C2+ research are discussed in this review.

Key words: Cu-based catalyst, CO2 electroreduction, Surface engineering, C2+ product, Modification strategy