Study of Pyridine-Mediated Electrochemical Reduction of CO2 to Methanol at High CO2 Pressure.
Study of Pyridine-Mediated Electrochemical Reduction of CO2 to Methanol at High CO2 Pressure.
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DOI：
10.1002/cssc.201600267
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发表时间：
2016-07
期刊：
影响因子：
8.4
通讯作者：
S. Rybchenko;D. Touhami;J. Wadhawan;S. Haywood
中科院分区：
文献类型：
--
作者：
S. Rybchenko;D. Touhami;J. Wadhawan;S. Haywood
在高CO2压力下，在铂电极上探索了最近提出的吡啶催化CO2还原合成甲醇的高效路线。在55巴(5.5兆帕)的二氧化碳下，恒电位和恒电流状态下的本体电解都产生了甲醇，第一次充电5-10C cm(-2)时，法拉第的产率高达10%。对于较长时间的电解，无论偏置条件和吡啶浓度如何，甲醇浓度都不能成比例增加，并且被限制在亚ppm水平。这一限制不能通过电极重新激活和/或预电解来消除，并且似乎是还原过程的固有特征。与整体电解结果一致的是，模拟支持的循环伏安分析表明，即使溶液中CO2浓度过高，在含吡啶的电解液中，析氢仍然是主要的电极反应。没有发现直接或耦合的二氧化碳减排的显著贡献。结果表明，CO2还原为甲醇是一个暂态过程，与电极电荷转移有很大的解耦关系。
The recently proposed highly efficient route of pyridine-catalyzed CO2 reduction to methanol was explored on platinum electrodes at high CO2 pressure. At 55 bar (5.5 MPa) of CO2 , the bulk electrolysis in both potentiostatic and galvanostatic regimes resulted in methanol production with Faradaic yields of up to 10 % for the first 5-10 C cm(-2) of charge passed. For longer electrolysis, the methanol concentration failed to increase proportionally and was limited to sub-ppm levels irrespective of biasing conditions and pyridine concentration. This limitation cannot be removed by electrode reactivation and/or pre-electrolysis and appears to be an inherent feature of the reduction process. In agreement with bulk electrolysis findings, the CV analysis supported by simulation indicated that hydrogen evolution is still the dominant electrode reaction in pyridine-containing electrolyte solution, even with an excess CO2 concentration in the solution. No prominent contribution from either a direct or coupled CO2 reduction was found. The results obtained suggest that the reduction of CO2 to methanol is a transient process that is largely decoupled from the electrode charge transfer.