This computational chemistry analysis compares the interactions of H₂O and CO₂ with zigzag graphene edges, and in particular their adsorption and desorption steps. We provide detailed information regarding the geometric and electronic factors that influence both their adsorption and desorption (of H₂ and CO) processes. Density functional theory results are compared with experimental information to offer heretofore unavailable insights into key aspects of the rate-limiting steps, inhibition phenomena and nanoscale differences in these two reactions. Thus, for example, the orientation and rotation of the adsorbing H₂O molecules are elucidated using intrinsic reaction coordinate calculations and molecular orbital analysis, and these results complement recent pulse field gradient NMR measurements and molecular dynamics calculations. Such mechanistic findings reveal the H₂O adsorption process to be a slow rotational phenomenon whereas the low-temperature H₂ desorption is geometrically constrained by the presence of contiguous (di)hydrogenated carbon atoms with or without hydroxyl groups. This surface-assisted desorption mechanism is proposed to be responsible for the formation of hexagonal pits during the graphite-H₂O reaction. Similar insights were obtained for the graphene-CO₂ reaction. Mechanistic schemes are proposed for the desorption products observed in experiments, distinguishing zigzag from armchair sites.

该计算化学分析比较了H ₂ O和CO ₂与之字形石墨烯边缘的相互作用，特别是它们的吸附和解吸步骤。我们提供有关影响其H ₂和CO吸附和解吸的几何和电子因素的详细信息。将密度泛函理论的结果与实验信息进行比较，以提供迄今为止对这两个反应中限速步骤，抑制现象和纳米级差异的关键方面尚无可用的见解。因此，例如，吸附H ₂的取向和旋转使用本征反应坐标计算和分子轨道分析来阐明O分子，这些结果补充了最近的脉冲场梯度NMR测量和分子动力学计算。这种机理上的发现表明，H ₂ O的吸附过程是一个缓慢的旋转现象，而低温H _2的解吸在几何上受到具有或不具有羟基的连续的（二）氢化碳原子的限制。有人提出这种表面辅助解吸机制负责在石墨-H ₂ O反应过程中形成六边形凹坑。对于石墨烯-CO ₂也获得了类似的见解。反应。针对在实验中观察到的解吸产物，提出了机械方案，以区分锯齿形和扶手椅形。