在酸溶液中使用MnOx/IrOx作为选择性氧进化电催化剂
Johannes G Vos1, Tim A Wezendonk2, Adriaan W Jeremiasse3
1Leiden Institute of Chemistry , Leiden University , PO Box 9502, 2300 RA Leiden , The Netherlands.
Journal of the American Chemical Society
|July 20, 2018
概括
在氧化 (IrOx) 上沉积的氧化 (MnOx) 薄膜显著提高了氧化演化反应 (OER) 选择性,而不是演化反应 (CER). 这种MnOx覆盖层起到屏障作用,阻碍离子输送,提高能源应用的OER效率.
科学领域:
- 电化学
- 材料科学
- 催化剂
背景情况:
- 氧进化反应 (OER) 和进化反应 (CER) 是重要的电化学过程.
- 开放式能源对太阳能转化 (水分离) 至关重要,而可再生能源对化工生产至关重要.
- 由于链接的催化中间体,特别是在酸性介质中,实现OER对CER的选择性具有挑战性.
研究的目的:
- 调查氧化 (MnOx) 催化剂的OER与CER选择性.
- 探索MnOx作为酸溶液中的选择性OER催化剂的潜力.
主要方法:
- 薄薄的MnOx薄膜 (∼5-20 nm) 在含水的氧化/玻璃碳 (IrOx/GC) 上的电解.
- 旋转环盘电极电压测量以评估催化活性和选择性.
- 在线电化学质谱 (OEMS) 用于识别反应产物.
- 使用扫描电子显微镜 (SEM),传输电子显微镜 (TEM) 和X射线光电子光谱 (XPS) 的现场表征.
主要成果:
- 在IrOx/GC上沉积MnO,在30mMCl-中将CER选择性从86%降低到<7%.
- MnOx膜作为一个高度选择性的OER催化剂.
- SEM,TEM和XPS分析表明MnOx膜作为一个透的上层,而不是一个催化活性相.
结论:
- 薄薄的MnOx膜有效地抑制了基于IrOx的演变反应.
- MnOx覆盖层的机制涉及阻碍离子运输而不是直接的催化活性.
- 这种方法为提高对能源转换相关的电化学系统的OER选择性提供了一个有希望的策略.
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