物理化学学报

所属专题: CO2还原

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面向CO2电化学转化的铜基催化剂研究进展

孟怡辰, 况思宇, 刘海, 范群, 马新宾, 张生   

  1. 天津大学化工学院, 绿色合成与转化教育部重点实验室, 天津 300072
  • 收稿日期:2020-06-12 修回日期:2020-06-28 录用日期:2020-06-29 发布日期:2020-07-02
  • 通讯作者: 张生 E-mail:sheng.zhang@tju.edu.cn
  • 基金资助:
    天津市重大科技专项(18ZXJMTG00180,19ZXNCGX00030)资助项目

Recent Advances in Electrochemical CO2 Reduction Using CopperBased Catalysts

Yichen Meng, Siyu Kuang, Hai Liu, Qun Fan, Xinbin Ma, Sheng Zhang   

  1. Key Laboratory for Green Chemical Technology of Ministry of Education, Collaborative Innovation Centre of Chemical Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
  • Received:2020-06-12 Revised:2020-06-28 Accepted:2020-06-29 Published:2020-07-02
  • Supported by:
    The project was supported by the Key Research and Development Project of Tianjin (18ZXJMTG00180, 19ZXNCGX00030)

摘要: 化石燃料的大量使用造成大气中CO2含量不断上升,带来了一系列气候及环境问题。将温室气体CO2进行捕集并转化利用有助于缓解能源短缺和全球变暖等问题,其中电化学技术因其具有温和可控的工作条件以及与可再生能源的相容性等特点,成为了一种很有前景的CO2转化利用技术。铜催化剂因其在电化学还原CO2过程中可以产生高价值的碳氢化合物而受到广泛关注与研究,但是有效产物的选择性依然较低,特别是C2+物种。因此提高铜基催化剂表面产物选择性成为了该领域研究难点与热点。为此,本文主要介绍了近五年不同改性方式的Cu基催化剂在选择性制备C2+产物方面的研究进展,概述了可能的反应机理并且总结了影响产物选择性的因素,最后提出了该领域进一步的研究方向与展望。

关键词: 二氧化碳, 电化学还原, Cu基催化剂, C2+产物, 选择性

Abstract: Burning of fossil fuels increases CO2 concentration in the atmosphere, resulting in a series of climate- and environment-related concerns such as global warming, sea-level rise, and melting of glaciers. Therefore, utilization of renewable energy to reduce the CO2 concentration, in order to realize a sustainable development, is urgent. Capturing and utilizing CO2, a greenhouse gas, can not only address these concerns but also alleviate the current scenario of energy shortage. Thermal catalytic CO2 hydrogenation offers various pathways with high conversion efficiencies to produce fuels and industrial chemicals including CO, HCOOH, CH3OH, and CH4. However, CO2 is chemically inert due to the highly stable C=O bond. Thus, harsh reaction conditions such as high temperature and pressure are required for CO2 hydrogenation.
Electrocatalytic CO2 reduction using renewable electricity and water is a promising alternative to thermocatalysis. This technology can not only store and transport the intermittent solar or wind energy but can also use water as the proton source instead of H2, which is indispensable for thermal CO2 hydrogenation. Electrochemical CO2 reduction under ambient conditions is a proton-coupled electron transfer process. The key to promote the electrochemical reduction of CO2 is to develop highly selective and active catalysts with high stability. Among various CO2 electrocatalysts, copper-based catalysts have attracted significant attention and have been extensively investigated, since they exhibit good selectivity and efficiency for the reduction of CO2 to hydrocarbons and alcohols. A broad range of products, up to 16 different gases and liquids, can be obtained in the CO2electroconversion on copper. Copper is the only metal that has a negative adsorption energy for *CO and a positive adsorption energy for *H. Thus, it has a unique property of generating >2e- transfer products. However, selectivity of the target product is still low, especially for high value-added C2+ species (C2H4, C2H5OH, CH3COOH, CH3CHO, n-C3H7OH, etc.).
The selectivity of various products on copper-based catalysts could be enhanced by surface engineering techniques such as tuning the morphologies, particle sizes, surface facets, strains levels, and atomic coordination. Electrolyte engineering could also aid in CO2 electroreduction. Therefore, improving the selectivity of C2+ products by modifying copper-based catalysts could be a hot research topic. In addition, C-C coupling is a key step in forming C2+ products, though the C2+ product formation pathway is complex, and the mechanisms are still unclear. Considering these, this paper mainly reviews the research progress in copper-based catalysts producing C2+ species in the last five years. It also discusses the possible reaction mechanisms and the factors that affect the product selectivities. In the end, further research directions are proposed.

Key words: Carbon dioxide, Electrochemical reduction, Copper-based catalysts, C2+ products, Selectivity

MSC2000: 

  • O646