在CO2降电过程中,研究氧化/氧化物衍生的铜电极中增强的C2+选择性
Qiong Lei1, Hui Zhu1, Kepeng Song1
1Advanced Membranes and Porous Materials Center, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
Journal of the American Chemical Society
|February 12, 2020
概括
氧化物/氧化物衍生铜电极在减少二氧化碳方面提高了C2+产品的选择性. 这种增强的选择性源于碎片化纳米铜粒和暴露的高指数面,而不是特定的铜氧化状态.
科学领域:
- 电化学
- 材料科学
- 催化剂
背景情况:
- 氧化物/氧化物衍生铜电极在电催化降低CO2过程中对C2+产品具有很高的选择性.
- 这种增强的选择性背后的原因尚未完全被理解,并且仍在争论中.
研究的目的:
- 研究铜氧化状态和电极结构在电催化二氧化碳还原反应 (CO2RR) 中的作用.
- 为了阐明氧化物/氧化物衍生铜电极中增强的C2+选择性的起源.
主要方法:
- 两种混合氧化状态的铜电极 (HQ-Cu和AN-Cu) 的制备.
- 聚焦离子束 (FIB) 用于样本提取.
- 电子显微镜 (EM) 和电子能量损失光谱 (EELS) 用于分析铜物种的分布和演变.
- 使用预处理的电极进行控制实验.
主要成果:
- 所有铜电极,无论初始状态如何,都在CO2RR过程中被减少到Cu0.
- 预处理的电极,完全减少到Cu0,表现出更高的C2+选择性.
- 在负电位下,氧化物/氧化水晶分裂成纳米尺寸的不规则的Cu粒.
- 碎片化造成了粒度边界和暴露的高指数面,促进了C-C合.
结论:
- 增强的C2+选择性不是由于特定的铜氧化状态,而是由于电极的结构演变.
- 氧化物/氧化水前体的碎片化成纳米粒,以及高指数面的暴露是改善C-C合的关键.
- 先进的特征技术为CO2RR过程中的电极行为提供了详细的见解.
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