在银催化剂上捕获的CO2的电还原:捕获剂和质子源的影响
Robert Michael Kowalski1, Avishek Banerjee1, Chudi Yue1
1Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095, United States.
Journal of the American Chemical Society
|July 22, 2024
概括
研究捕获的二氧化碳电还原 (c-CO2RR),这项研究发现质子源显著影响反应性和选择性. 虽然甲氧化物表现有前途,但演化反应 (HER) 仍然在银催化剂中占主导地位.
科学领域:
- 电化学
- 碳捕获和利用
- 催化剂
背景情况:
- 通过绕过二氧化碳分离,直接电降碳 (c-CO2RR) 提供了一种能源高效的碳再利用途径.
- 了解捕获剂和质子源的影响对于优化c-CO2RR过程至关重要.
研究的目的:
- 通过使用银电催化剂,研究不同捕获剂 (甲氧化物,NH3,二碳酸盐) 和质子源对捕获的二氧化碳 (c-CO2RR) 的直接电还原的影响.
- 在不同的条件下阐明c-CO2RR,自由CO2电还原和演化反应 (HER) 之间的相互作用.
主要方法:
- 理论计算 (密度函数理论) 和实验电化学研究的结合.
- 使用旋转筒电极电池来控制质量传输.
- 分析了质子源酸度 (pKa) 对反应途径的影响.
主要成果:
- 质子源酸度 (较低的pKa) 增强了c-CO2RR反应,但也有利于银的演化反应 (HER).
- 在银催化剂上,无论采集剂或溶剂如何,都发现HER比c-CO2RR占主导地位.
- 甲氧化物作为潜在的捕获剂出现,与氨基基系统相比,其HER活性较低,尽管c-CO2RR仍然是次要的.
结论:
- 质子源在c-CO2RR中起着关键作用,影响反应性和选择性.
- 为了实现高效的c-CO2RR,需要克服白银催化剂的优惠HER,需要改善催化剂设计.
- 甲氧化物是直接减少二氧化碳的有希望的替代捕获剂,但需要进一步优化才能使c-CO2RR具有竞争力.
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