Kinetics of Hydride Transfer from Catalytic Metal-Free Hydride Donors to CO 2
Kinetics of Hydride Transfer from Catalytic Metal-Free Hydride Donors to CO 2
复制标题
氢化物从催化无金属氢化物供体向CO 2 转移的动力学
DOI：
10.1021/acs.jpclett.0c03662
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Glusac, Ksenija D.
中科院分区：
文献类型：
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作者：
Weerasooriya, Ravindra B.;Gesiorski, Jonathan L.;Alherz, Abdulaziz;Ilic, Stefan;Hargenrader, George N.;Musgrave, Charles B.;Glusac, Ksenija D.
选择性还原二氧化碳为甲酸盐是光电催化领域持续面临的挑战。为了提供机理见解，我们研究了从一系列无金属氢化物供体到二氧化碳的氢化物转移（HT）动力学。通过使用 Marcus 氢化物转移形式对观察到的实验和计算的 HT 势垒对热力学驱动力的依赖性进行建模，以深入了解重组能对反应动力学的影响。我们的结果表明，即使发现了最理想的氢化物供体，HT 转化为 CO2 的动力学也会表现出缓慢的动力学（在 -0.1 eV 驱动力下每秒<100 次转换），这表明传统的 HT 可能不是 CO2 太阳能转化为甲酸盐的合适机制。我们建议传统的 HT 机制不应被考虑用于 CO2 还原催化，并认为之前提出的用于解决该反应的热力学限制的正交 HT 机制也可能导致 CO2 还原成甲酸盐的动力学障碍较低。
Selective reduction of CO2to formate represents an ongoing challenge in photoelectrocatalysis. To provide mechanistic insights, we investigate the kinetics of hydride transfer (HT) from a series of metal-free hydride donors to CO2. The observed dependence of experimental and calculated HT barriers on the thermodynamic driving force was modeled by using the Marcus hydride transfer formalism to obtain the insights into the effect of reorganization energies on the reaction kinetics. Our results indicate that even if the most ideal hydride donor were discovered, the HT to CO2would exhibit sluggish kinetics (<100 turnovers per second at −0.1 eV driving force), indicating that the conventional HT may not be an appropriate mechanism for solar conversion of CO2to formate. We propose that the conventional HT mechanism should not be considered for CO2reduction catalysis and argue that the orthogonal HT mechanism, previously proposed to address thermodynamic limitations of this reaction, may also lead to lower kinetic barriers for CO2reduction to formate.