通过修改第一个和第二个协调球来调整单原子催化剂的酸氧降低选择性
Cheng Tang1, Ling Chen1, Haijing Li2
1School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide, SA 5005, Australia.
了解催化活性位点是高效电催化剂的关键. 这项研究表明,局部结构,而不仅仅是单个原子,决定了单原子催化剂 (SAC) 氧降解反应 (ORR) 的选择性.
科学领域:
- 电化学
- 催化剂
- 材料科学
背景情况:
- 多电子电催化反应中的产品选择性对于能量转化和化学合成至关重要.
- 一个重大挑战是对精确的催化活性位点的理解有限.
- 单原子催化剂 (SAC) 提供高原子利用率,但需要详细的活性位点特征.
研究的目的:
- 在单原子催化剂 (SAC) 中研究酸氧还原反应 (ORR) 的结构-特性关系.
- 证明局部协调环境, 不仅仅是中央原子,
- 阐明ORR选择性针对特定路径的机制.
主要方法:
- 使用理论预测和实验验证.
- 使用X射线吸收细结构 (XAFS) 分析探测局部结构.
- 现场红外 (IR) 光谱监测反应中间体和活性位点.
主要成果:
- 局部结构,包括第一和第二协调球 (CSs),协同决定了电催化反应.
- 通过修改协调球来调整-SAC (Co-SAC) 的ORR选择性.
- 活动部位从中心的C原子转移到相邻的O原子,优化电子结构和*OOH吸附.
结论:
- SACs的分子水平局部结构是电催化选择性的主要决定因素.
- 定制协调球可以精确控制ORR路径.
- 这项工作实现了酸性H2O2电合成的高选择性 (> 95%),证明了催化剂设计的新范式.
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