物理化学学报 >> 2021, Vol. 37 >> Issue (5): 2009021.doi: 10.3866/PKU.WHXB202009021

所属专题: CO2还原

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用于二氧化碳电催化还原的电解器研究进展

高敦峰1,*(), 魏鹏飞1, 李合肥1,2, 林龙1,2, 汪国雄1,2,*(), 包信和1   

  1. 1 中国科学院大连化学物理研究所,中国科学院洁净能源创新研究院,催化基础国家重点实验室,辽宁 大连 116023
    2 中国科学院大学,北京 100049
  • 收稿日期:2020-09-04 录用日期:2020-09-24 发布日期:2020-10-09
  • 通讯作者: 高敦峰,汪国雄 E-mail:dfgao@dicp.ac.cn;wanggx@dicp.ac.cn
  • 作者简介:Dunfeng Gao is currently an associate professor at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences (DICP, CAS). He obtained B.Sc. degree from China University of Petroleum in 2009 and Ph.D. degree from the DICP in 2015. Then he worked as a postdoctoral researcher at the Ruhr University Bochum and the Fritz Haber Institute of the Max Planck Society in Germany (2015-2019). In 2019, he moved back to the DICP as an associate professor. His research focuses on electrocatalysis including CO2 electroreduction, CH4 electrooxidation and water electrolysis
    Guoxiong Wang is currently a full professor at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences (DICP, CAS). He obtained B.Sc. degree from Wuhan University in 2000 and Ph.D. degree from the DICP in 2006. After a one-year stay at the DICP as an assistant professor (2006-2007), he worked as a postdoctoral researcher at the Hokkaido University in Japan (2007-2010). In December 2010, he moved back to the DICP as an associate professor and promoted to a full professor in 2015. His research focuses on energy storage and conversion, electrocatalytic CO2 reduction and fuel cell
  • 基金资助:
    国家重点研发计划(2016YFB0600901);国家自然科学基金(21573222);国家自然科学基金(91545202);国家自然科学基金(22002155);中国科学院洁净能源创新研究院合作基金(DNL180404);中国科学院洁净能源创新研究院合作基金(DNL201924);大连化物所DMTO基金(DICP DMTO201702);大连市杰出青年基金(2017RJ03);中国科学院战略性先导专项(XDB17020200);中国科学院青年创新促进会(Y201938)

Designing Electrolyzers for Electrocatalytic CO2 Reduction

Dunfeng Gao1,*(), Pengfei Wei1, Hefei Li1,2, Long Lin1,2, Guoxiong Wang1,2,*(), Xinhe Bao1   

  1. 1 State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning Province, China
    2 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2020-09-04 Accepted:2020-09-24 Published:2020-10-09
  • Contact: Dunfeng Gao,Guoxiong Wang E-mail:dfgao@dicp.ac.cn;wanggx@dicp.ac.cn
  • About author:Email: wanggx@dicp.ac.cn (G.W.); Tel.: +86-411-84379976 (G.W.)
    Email: dfgao@dicp.ac.cn (D.G.); Tel.: +86-411-84379128 (D.G.)
  • Supported by:
    the National Key R & D Program of China(2016YFB0600901);the National Natural Science Foundation of China(21573222);the National Natural Science Foundation of China(91545202);the National Natural Science Foundation of China(22002155);Dalian National Laboratory for Clean Energy, China(DNL180404);Dalian National Laboratory for Clean Energy, China(DNL201924);Dalian Institute of Chemical Physics, China(DICP DMTO201702);Dalian Outstanding Young Scientist Foundation, China(2017RJ03);the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB17020200);the CAS Youth Innovation Promotion(Y201938)

摘要:

可再生能源驱动的二氧化碳电催化还原反应(CO2RR)是实现CO2高效转化和利用的有效途径。电解器的理性设计对于提高CO2RR性能及其工业放大应用具有重要意义。电解器构型及其操作条件在很大程度上决定了电极附近的局部反应环境,从而调变催化性能。本文深度剖析了三种CO2电解器(H型电解池、流动电解池和膜电极电解池)的研究进展和现状,结合文献报道,在电流密度、法拉第效率、能量效率和稳定性等四个关键性能参数上比较和讨论了不同电解器构型的优缺点及其对CO2RR性能的影响。面向实际应用的CO2RR研究应该把工业级电流密度作为提高其它三个指标的前提。尽管目前还存在一些问题和挑战,膜电极电解器被认为是最具工业应用前景的技术方案。本文最后提出了一些可能的研究策略和机遇,展望了该领域的未来发展趋势。

关键词: CO2电解器, 电催化还原, 能量效率, 工业级电流密度, 流动池, 膜电极

Abstract:

The electrocatalytic CO2 reduction reaction (CO2RR) driven by renewable energy is an efficient approach to achieve the conversion and utilization of CO2. In this context, CO2RR has become an emerging research focus in the field of electrocatalysis over the past decade. While a large number of nanostructured catalysts have been developed to accelerate CO2RR, the tradeoff between activity and selectivity usually renders the overall electrocatalytic performance very poor. Beyond catalyst design, rationally designing electrolyzers is also of substantial importance for improving the CO2RR performance and achieving its scale-up for practical applications. To a large extent, the electrolyzer configuration determines the local reaction environment near an electrode by affecting the process conditions, thereby resulting in remarkably different electrocatalytic performances. To be techno-economically viable, the performance of CO2 electrolyzers is expected to be at least comparable to that of the current state-of-the-art proton exchange membrane (PEM) water electrolyzers, with regard to their activity, selectivity, and stability. Researchers have made great progress in the development of CO2 electrolyzers over the past few years, but they are also facing many issues and challenges. This review aims to provide an in-depth analysis of the research progress and status of current CO2 electrolyzers including H-cell, flow-cell, and membrane electrode assembly cell (MEA-cell) electrolyzers. Herein, operation at industrial current densities (> 200 mA∙cm−2) is set as a basis when these electrolyzers are discussed and compared in terms of the four main figures of merit (current density, Faradic efficiency, energy efficiency and stability) that describe the CO2RR performance of an electrolyzer. The advantages and drawbacks of each electrolyzer are discussed and highlighted with emphasis on the key achievements reported to date. Compared to conventional H-cell electrolyzers that work well in mechanistic studies, the newly developed electrolyzers using gas diffusion electrodes, both flow-cell and MEA-cell electrolyzers, are able to break the limitation of CO2 solubility in water and acquire industrial current densities. Although flow-cell electrolyzers have achieved current densities exceeding 1 A∙cm−2, they suffer from low energy efficiencies because of the significant iR drop and poor stability owing to the use of alkaline electrolytes. These issues can be overcome in the case of zero-gap MEA-cell electrolyzers with ion exchange membranes being as solid electrolytes. The anion exchange membrane (AEM)-based CO2 electrolyzers are at the center of the current research, as they demonstrate promising activity and selectivity toward specific CO2RR products and exhibit excellent stability for over thousands of hours in few cases. Meanwhile, the crossover of CO2 and liquid products from the cathode to the anode through the membrane tends to lower the utilization efficiency of the CO2 supplied to the AEM electrolyzers. MEA-cell electrolyzers using cation exchange membranes and bipolar membranes have also been explored; however, neither of them have shown satisfactory CO2RR performance. The development of new polymer electrolyte membranes and ionomers would help address these problems. While issues and challenges still exist, MEA-cell electrolyzers hold the greatest promise for practical applications. As concluding remarks, research strategies and opportunities for the future have been proposed to accelerate the development of CO2RR technology for practical applications and to deepen the mechanistic understanding behind improved performance. This review provides new insights into rational electrolyzer design and guidelines for researchers in this field.

Key words: CO2 electrolyzers, Electrocatalytic reduction, Energy efficiency, Industrial current density, Flow cell, Membrane electrode assembly

MSC2000: 

  • O643