Systematic Analysis of Electrochemical CO2 Reduction with Various Reaction Parameters using Combinatorial Reactors

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• 作者：Hiroshi Hashiba ; Satoshi Yotsuhashi ; Masahiro Deguchi ; Yuka Yamada
• 刊名：ACS Combinatorial Science
• 出版年：2016
• 出版时间：April 11, 2016
• 年：2016
• 卷：18
• 期：4
• 页码：203-208
• 全文大小：390K
• 年卷期：0
• ISSN：2156-8944

文摘

Applying combinatorial technology to electrochemical CO₂ reduction offers a broad range of possibilities for optimizing the reaction conditions. In this work, the CO₂ pressure, stirring speed, and reaction temperature were varied to investigate the effect on the rate of CO₂ supply to copper electrode and the associated effects on reaction products, including CH₄. Experiments were performed in a 0.5 M KCl solution using a combinatorial screening reactor system consisting of eight identical, automatically controlled reactors. Increasing the CO₂ pressure and stirring speed, or decreasing the temperature, steadily suppressed H₂ production and increased the production of other reaction products including CH₄ across a broad range of current densities. Our analysis shows that the CO₂ pressure, stirring speed, and reaction temperature independently contributed to the limiting rate of CO₂ supply to the electrode (J_lim). At a constant temperature, the limiting current density of CH₄ increased proportionally with J_lim, illustrating that the production rate of CH₄ was proportional to CO₂ supply. Varying the CO₂ pressure and stirring speed hardly affected the maximum Faradaic efficiency of CH₄ production. However, changes to the reaction temperature showed a significant contribution to CH₄ selectivity. This study highlights the importance of quantitative analysis of CO₂ supply in clarifying the role of various reaction parameters and understanding more comprehensively the selectivity and reaction rate of electrochemical CO₂ reduction.