Qin Xueping, Hansen Heine A, Honkala Karoliina, Melander Marko M
Department of Energy Conversion and Storage, Technical University of Denmark, Anker Engelunds Vej Building 301, Kgs. Lyngby, 2800, Denmark.
Department of Chemistry, Nanoscience Center, University of Jyväskylä, P.O. Box 35, FI-40014, Jyväskylä, Finland.
Nat Commun. 2023 Nov 22;14(1):7607. doi: 10.1038/s41467-023-43300-4.
The underlying mechanism of cation effects on CORR remains debated. Herein, we study cation effects by simulating both outer-sphere electron transfer (OS-ET) and inner-sphere electron transfer (IS-ET) pathways during CORR via constrained density functional theory molecular dynamics (cDFT-MD) and slow-growth DFT-MD (SG-DFT-MD), respectively. Our results show without any cations, only OS-ET is feasible with a barrier of 1.21 eV. In the presence of K (Li), OS-ET shows a very high barrier of 2.93 eV (4.15 eV) thus being prohibited. However, cations promote CO activation through IS-ET with the barrier of only 0.61 eV (K) and 0.91 eV (Li), generating the key intermediate (adsorbed CO[Formula: see text]). Without cations, CO-to-COFormula: see text conversion cannot proceed. Our findings reveal cation effects arise from short-range Coulomb interactions with reaction intermediates. These results disclose that cations modulate the inner- and outer-sphere pathways of CORR, offering substantial insights on the cation specificity in the initial CORR steps.
阳离子对析氧反应（CORR）的潜在影响机制仍存在争议。在此，我们分别通过受限密度泛函理论分子动力学（cDFT-MD）和慢增长密度泛函理论分子动力学（SG-DFT-MD）模拟析氧反应过程中的外层电子转移（OS-ET）和内层电子转移（IS-ET）途径，来研究阳离子的影响。我们的结果表明，在没有任何阳离子的情况下，只有外层电子转移是可行的，其势垒为1.21电子伏特。在存在钾（锂）的情况下，外层电子转移显示出非常高的势垒，分别为2.93电子伏特（4.15电子伏特），因此被禁止。然而，阳离子通过内层电子转移促进一氧化碳活化，其势垒仅为0.61电子伏特（钾）和0.91电子伏特（锂），生成关键中间体（吸附的CO[化学式：见原文]）。没有阳离子，一氧化碳到CO[化学式：见原文]（吸附态）的转化无法进行。我们的研究结果表明，阳离子的影响源于与反应中间体的短程库仑相互作用。这些结果揭示了阳离子调节析氧反应的内层和外层途径，为析氧反应初始步骤中的阳离子特异性提供了重要见解。
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