在近中性KCl电解质中选择性和高电流CO2电降解为多碳产品
Xiao Zhang1, Jiachen Li1, Yuan-Yao Li1,2
1Department of Chemistry and BioX, Stanford University, Stanford, California 94305, United States.
Journal of the American Chemical Society
|February 22, 2021
概括
这项研究提出了一种稳定和选择性的电催化剂,用于将二氧化碳 (CO2) 减少为有价值的多碳产品. 气体扩散层电极上的新铜催化剂在近中性电解质中有效运行,克服了CO2减排方面的挑战.
科学领域:
- 电化学
- 催化剂
- 可再生能源
背景情况:
- 减少大气中的二氧化碳对于缓解气候变化至关重要.
- 电催化CO2降解 (CO2RR) 到多碳 (C2+) 产品在选择性和稳定性方面面临挑战,特别是在高电流密度下.
- 现有的CO2RR方法经常与性介质中的催化剂降解作斗争.
研究的目的:
- 开发一种稳定且有选择性的电催化剂,用于CO2RR到C2+产品.
- 研究铜电催化剂在疏水气扩散层 (GDL) 电极上的性能.
- 在近中性和性电解质中比较CO2的RR性能.
主要方法:
- 铜催化剂的电子沉积在疏水性多孔气体扩散层 (GDL) 上.
- 使用近中性KCl和性KOH电解质在H电池和流电池组合中测试Cu/GDL电极.
- 构建和操作具有周期性pH调节的双电极CO2电解器.
主要成果:
- 在接近中性的KCl电解质中,Cu/GDL电极实现了接近100mA cm-2的高C2+部分电流密度.
- 在KCl中观察到稳定的CO2RR性能,优于KOH,基媒介中的催化剂不稳定性归因于Cu蚀刻/腐蚀.
- 一个流电池电解仪在30小时内在150mA cm-2下表现出稳定的CO2RR活性和选择性,达到约75%的法拉第效率和40%的C2+产品能效.
结论:
- 一个简单的 Cu/GDL 电极为稳定和选择性的 CO2RR 到 C2+产品提供了一个有前途的平台.
- 与性介质相比,近中性电解质通过抑制铜腐蚀显著提高了催化剂的稳定性.
- 开发的CO2电解系统显示了高效碳捕获和利用技术的潜力.
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