Catalyst Preoxidation and EDTA Electrolyte Additive Remedy Activity and Selectivity Declines During Electrochemical CO2 Reduction
Catalyst Preoxidation and EDTA Electrolyte Additive Remedy Activity and Selectivity Declines During Electrochemical CO2 Reduction
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DOI：
10.1021/acs.jpcc.8b08794
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发表时间：
2019-01-31
影响因子：
3.7
通讯作者：
Strasser, Peter
中科院分区：
文献类型：
--
作者：
Jovanov, Zarko P.;de Araujo, Jorge Ferreira;Strasser, Peter
从可再生能源获得的剩余电力需要适当的大规模储存。未来的二氧化碳电解装置有望提供一种方便的途径，以合成燃料的形式储存大量多余的电力，如甲烷，乙烯或含氧化合物。在这项工作中，我们探索了支持长期稳定性的策略，在电催化CO2转化为CO，碳氢化合物和醇。我们展示了如何电化学预氧化的铜电极作为催化剂，可以确保更持久的活性和选择性的CO2还原。我们证明，EDTA作为电解质添加剂可以是一个可靠的杂质清除剂，特别是结合在阳极电位的催化剂预处理。在阳极表面预氧化和足够的添加剂的情况下，在模型多晶铜上电解20小时后，乙烯的前所未有的速率保持率为91%。此外，我们确定EDTA表现出额外的作用，专门作为螯合剂。我们建议，局部pH稳定和增加的CO2浓度附近的电极表面也有助于长期稳定性和提高CO2还原选择性。
Surplus electricity obtained from renewable energy sources requires suitable large-scale storage. Future CO2 electrolysis devices promise to offer a convenient route to store large quantities of excess electricity in the form of synthetic fuels, such as methane, ethylene, or oxygenates. In this work, we explored the strategies to support long-term stability in electrocatalytic CO2 conversion to CO, hydrocarbons, and alcohols. We show how electrochemical preoxidation of copper electrodes used as catalyst may ensure longer-lasting activity and selectivity in CO2 reduction. We demonstrate that EDTA as an electrolyte additive can be a realiable impurity scavenger, especially combined with a catalyst pretreatment at anodic potentials. An unprecedented rate retention after 20 h electrolysis on a model polycrystalline copper was 91% for ethylene in the case when both anodic surface preoxidation and sufficient additive are applied. Additionally, we established that EDTA exhibits an additional role to being exclusively a chelating agent. We propose that local pH stabilization and increased CO2 concentration near the electrode surface also contribute to long-term stability and improved CO2 reduction selectivities.