Han Erxun, Fang Wei, Stamatakis Michail, Richardson Jeremy O, Chen Ji
School of Physics, Peking University, Beijing 100871, China.
Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing 100871, People's Republic of China.
J Phys Chem Lett. 2022 Apr 14;13(14):3173-3181. doi: 10.1021/acs.jpclett.2c00520. Epub 2022 Apr 1.
It is commonly believed that it is unfavorable for adsorbed H atoms on carbonaceous surfaces to form H without the help of incident H atoms. Using ring-polymer instanton theory to describe multidimensional tunnelling effects, combined with electronic structure calculations, we find that these quantum-mechanical simulations reveal a qualitatively different picture. Recombination of adsorbed H atoms, which was believed to be irrelevant at low temperature due to high barriers, is enabled by deep tunnelling, with reaction rates enhanced by tens of orders of magnitude. Furthermore, we identify a new path for H recombination that proceeds via multidimensional tunnelling but would have been predicted to be unfeasible by a simple one-dimensional description of the reaction. The results suggest that hydrogen molecule formation at low temperatures are rather fast processes that should not be ignored in experimental settings and natural environments with graphene, graphite, and other planar carbon segments.
人们普遍认为，在没有入射氢原子的帮助下，碳质表面吸附的氢原子不利于形成氢气。利用环聚合物瞬子理论描述多维隧穿效应，并结合电子结构计算，我们发现这些量子力学模拟揭示了一种截然不同的情况。吸附氢原子的重组，由于势垒高，在低温下被认为是无关紧要的，但通过深度隧穿得以实现，反应速率提高了数十个数量级。此外，我们确定了一条氢重组的新路径，该路径通过多维隧穿进行，但简单的一维反应描述预计该路径是不可行的。结果表明，在低温下氢分子的形成是相当快速的过程，在含有石墨烯、石墨和其他平面碳片段的实验环境和自然环境中不应被忽视。
