在水中跟踪质质子还原催化剂的结构和电子配置
Dooshaye Moonshiram, Carolina Gimbert-Suriñach1, Alexander Guda2
1Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology , Avinguda Països Catalans 16, 43007 Tarragona, Spain.
Journal of the American Chemical Society
|July 26, 2016
概括
这项研究使用X射线暂时吸收光谱 (X-TAS) 调查催化剂的演变. 该研究确定了关键的中间体,并确定了CoI物种的质子化作为改进燃料电池催化剂的速度限制步骤.
科学领域:
- 光催化和电催化
- 协调化学
- 光谱学和反应动力学
背景情况:
- 在燃料电池等可再生能源技术中开发高效的催化剂至关重要.
- 由于其可调节的电子特性,基于的复合物是进化催化物的有希望的候选物.
- 了解反应机制和识别瞬态中间体是催化剂优化的关键.
研究的目的:
- 阐明由宏环复合物催化的光诱导进化的现场机制.
- 使用时间分辨率光谱识别和描述在催化周期中形成的过渡性中间体.
- 确定由复合物催化的演化反应的速度限制步骤.
主要方法:
- 使用X射线瞬时吸收光谱 (X-TAS) 实时探测催化剂的电子和结构变化.
- 使用X射线吸收近边结构 (XANES) 和扩展X射线吸收细结构 (EXAFS) 进行详细的结构分析.
- 综合密度函数理论 (DFT) 计算,包括分子轨道 (DFT-MO) 和有限差异方法 (FDM),用于物种分配和机械建模.
主要成果:
- 在二进制系统中确定了具有51 ns电子转移动量的扭曲Co (II) 中间体的现场形成.
- 在完整的光催化系统中,在纳米秒内观察到正方形平面 Co ((I) 物种的短暂形成,在微秒时间尺度上衰减.
- 确定Co (I) 中间体的质子化是催化循环中的速度限制步骤.
结论:
- 建立了由宏环复合物催化的演化反应的综合机械路径.
- 提供了对催化循环的独特动态见解, 对于设计燃料电池的先进催化剂至关重要.
- 这项研究突出了理解催化剂发展的短暂物种和反应动力学的重要性.
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