Theoretical Insights into Pyridinium-Based Photoelectrocatalytic Reduction of CO2
Theoretical Insights into Pyridinium-Based Photoelectrocatalytic Reduction of CO2
复制标题
DOI：
10.1021/ja300128e
复制
发表时间：
2012-05-09
影响因子：
15
通讯作者：
Carter, Emily A.
中科院分区：
文献类型：
--
作者：
Keith, John A.;Carter, Emily A.
吡啶阳离子在电化学中的作用已经被认为是已知的几十年，并且它们的自由基形式已经被提出作为现代光电催化CO2还原过程中的关键中间体。利用第一性原理密度泛函理论和连续溶剂化模型，我们计算了吡啶阳离子和相应的吡啶基自由基的酸度常数，以及它们的电化学氧化还原电位。与以前的假设相反，我们的研究结果表明，这些物种可以被排除在均相电化学的积极参与者。计算的酸度和氧化还原电位的比较表明，吡啶阳离子的行为与以前认为的不同，电极表面起着关键（但仍然未知）的作用，在吡啶还原。这项工作大大改变了吡啶催化的光电化学CO2还原的机理观点。
The role of pyridinium cations in electrochemistry has been believed known for decades, and their radical forms have been proposed as key intermediates in modern photoelectrocatalytic CO2 reduction processes. Using first-principles density functional theory and continuum solvation models, we have calculated acidity constants for pyridinium cations and their corresponding pyridinyl radicals, as well as their electrochemical redox potentials. Contrary to previous assumptions, our results show that these species can be ruled out as active participants in homogeneous electrochemistry. A comparison of calculated acidities and redox potentials indicates that pyridinium cations behave differently than previously thought, and that the electrode surface plays a critical (but still unknown) role in pyridinium reduction. This work substantially alters the mechanistic view of pyridinium-catalyzed photoelectrochemical CO2 reduction.