在电催化水氧化中活跃的表面电子孔丰富物种
Juan-Jesús Velasco-Vélez1,2, Emilia A Carbonio2,3, Cheng-Hao Chuang4
1Department of Heterogeneous Reactions, Max Planck Institute for Chemical Energy Conversion, Mülheim an der Ruhr 45470, Germany.
Journal of the American Chemical Society
|August 6, 2021
概括
氧化催化剂在酸性条件下通过表面激活水的Ir(V) 物种促进水的氧化. 大量物种没有直接参与,更薄的电极提高了催化剂的利用率.
科学领域:
- 电化学
- 材料科学
- 表面科学
背景情况:
- 氧化物/氧化物是硬酸性介质中氧化演化反应 (OER) 的主要候选物.
- 氧化铁的低超电位和高耐腐蚀性使其适用于苛刻的应用.
研究的目的:
- 在电催化水氧化过程中阐明活性中心的电子结构.
- 了解表面与散装物种在高性能Ir基催化剂中的作用.
主要方法:
- 使用了先进的表面和批量敏感X射线光谱.
- 使用专门设计的电极纳米制造.
- 进行了*ab initio*密度函数理论 (DFT) 的计算.
主要成果:
- 确定了表面上空的Ir5d状态的形成,与IrV物种相关,驱动水的激活.
- 观察到表面μ1-O和μ1-OH物种,而不是散装μ3-O,是水氧化的关键.
- 在OER期间排除了μ1-OO (peroxo) 种类的高覆盖率.
结论:
- 氧进化反应是表面控制的,由与单个原子结合的缺电子氧物种介导.
- 较薄的电极通过增加表面与体积的比率来提高材料的利用率,尽管有活跃物种的潜在沉.
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