使用悬浮的质子捐赠继电器和添加的基来控制与Mn复合物的二氧化碳还原过程中的产品选择性
Emma N Cook1, Ian M Courter1, Diane A Dickie1
1Department of Chemistry University of Virginia PO Box 400319 McCormick Rd Charlottesville VA 22904-4319 USA machan@virginia.edu.
Chemical science
|March 22, 2024
概括
研究人员开发了两种催化剂,用于减少氧气. 一种催化剂选择性地产生过氧化,而另一种是定量性的. 添加基因将选择性转移到水中,在一个案例中增强了活动.
科学领域:
- 无机化学 无机化学 有机化学
- 催化剂是一种催化剂.
- 电化学 电化学 电化学
背景情况:
- 氧降解反应 (ORR) 对于能量转化至关重要.
- 对ORR的均质催化剂的探索比铁或系统少.
- 非氨酸配体为金属催化剂提供可调节的电子和硬质性质.
研究的目的:
- 为了研究悬浮的质子捐赠继电器对基ORR催化剂的影响.
- 评估连接体修饰如何影响ORR.的活性和选择性.
- 了解ORR的机械路径与不同的质子源和复合体.
主要方法:
- 两种复合物的合成与基于双的配体:Mn(p-dhbpy) Cl (1) 和Mn(nPrdhbpy) Cl (2).
- 使用基于氨的质子源对ORR活性和选择性的电催化评估.
- 机理学研究涉及添加联基来探测质子转移和中间物种.
主要成果:
- 综合体1对H2O2具有64%的选择性,而综合体2对H2O2具有定量性.
- 对减少的Mn (II) 中心的O2结合是复合体1的速度决定性步骤.
- 添加一个结合基将选择性转移到H2O对于两个复合体,增强复合体2的活性.
- 基添加改变了Mn-hydroperoxo物种对复合物2的O-O键裂变的速度决定性步骤.
结论:
- 垂直继电器部分可以增强H2O2的选择性,但可能会由于结合而降低反应速度.
- 基添加可以通过缓冲质子活性来提高催化速率并改变产品选择性.
- 有悬挂继电器的催化剂显示了选择性氧气减少的潜力,但中间稳定可以限制最大速率.
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