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离子溶剂揭示了铜催化乙烯电合成的改变机制
An T Chu1, Yogesh Surendranath1
1Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
Journal of the American Chemical Society
|March 17, 2022
概括
在近距离溶剂中,铜电催化剂将一氧化碳 (CO) 转化为有价值的C2产品,如乙烯. 这项研究揭示了一种新的机制,涉及合电子转移 (PCET) 步骤,与水性条件不同.
科学领域:
- 电化学
- 催化剂
- 材料科学
背景情况:
- 对一氧化碳 (CO) 电还原的铜 (Cu) 催化对电解质成分敏感.
- 在水性介质中,C2产物形成在很大程度上不受pH或离子变化的影响,这表明pH独立的C-C合步骤.
- 通过改变界面电荷稳定,近距离溶剂可能会揭示新的机械路径.
研究的目的:
- 通过使用作为质子捐赠剂的二甲基硫化物 (dimethyl sulfoxide) 进行二氧化碳电减的研究.
- 探索受抑制的界面电荷稳定所青的替代机械路径.
- 在碳化合物电合成中调整产品选择性向更高阶产品.
主要方法:
- 使用多晶体Cu催化剂的电化学减少CO.
- 使用二甲基硫化物 (DMSO) 作为溶剂和作为质子捐赠物.
- 分析产品分布和电化学参数,包括Tafel斜率和Nernstian依赖性.
主要成果:
- CO电还原主要产生C2产物:乙烯,乙酸,乙烯基醇和乙,其中甲的含量最小.
- 观察到乙烯形成的低塔菲尔斜率 (27 ± 1 mV dec-1),与水系统形成对比.
- 证明了对乙烯形成的质子活动的纳尔斯蒂安依赖,表明准平衡的质子合电子转移 (PCET) 步骤.
结论:
- 溶剂环境和质子捐赠者对二氧化碳电还原机制产生了关键影响.
- 离子电解质暴露了涉及PCET的新机制路径,与水性介质中的不同.
- 这突出了通过溶剂和质子捐赠工程控制碳化合物电合成产品选择性的新策略.
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