Institute for Physical Chemistry, Georg-August University of Goettingen, Tammannstraße 6, Goettingen37077, Germany.
Department of Dynamics at Surfaces, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, Goettingen37077, Germany.
J Am Chem Soc. 2022 Nov 30;144(47):21791-21799. doi: 10.1021/jacs.2c10458. Epub 2022 Nov 18.
A detailed velocity-resolved kinetics study of NH thermal desorption rates from (2 × 2) O/Pt(111) is presented. We find a large reduction in the NH desorption rate due to adsorption of O-atoms on Pt(111). A physical model describing the interactions between adsorbed NH and O-atoms explains these observations. By fitting the model to the derived desorption rate constants, we find an NH stabilization on (2 × 2) O/Pt(111) of 0.147 eV compared to Pt(111) and a rotational barrier of 0.084 eV, which is not present on Pt(111). The model also quantitatively predicts the steric hindrance of NH diffusion on Pt(111) due to co-adsorbed O-atoms. The derived diffusion barrier of NH on (2 × 2) O/Pt(111) is 1.10 eV, which is 0.39 eV higher than that on pristine Pt(111). We find that Perdew Burke Ernzerhof (PBE) and revised Perdew Burke Ernzerhof (RPBE) exchange-correlation functionals are unable to reproduce the experimentally observed NH-O adsorbate-adsorbate interactions and NH binding energies at Pt(111) and (2 × 2) O/Pt(111), which indicates the importance of dispersion interactions for both systems.
我们对 NH 在（2×2）O/Pt(111) 表面的热脱附速率进行了详细的速度分辨动力学研究。我们发现由于 O 原子在 Pt(111)表面的吸附，NH 的脱附速率大大降低。一个描述吸附 NH 和 O 原子之间相互作用的物理模型解释了这些观察结果。通过将模型拟合到推导出来的脱附速率常数，我们发现与 Pt(111)相比，NH 在（2×2）O/Pt(111)上的稳定化能为 0.147 eV，旋转势垒为 0.084 eV，而在 Pt(111)上则不存在。该模型还定量预测了由于 co-adsorbed O 原子，NH 在 Pt(111)上扩散的空间位阻。NH 在（2×2）O/Pt(111)上的扩散势垒为 1.10 eV，比在原始 Pt(111)上的扩散势垒高 0.39 eV。我们发现，Perdew Burke Ernzerhof（PBE）和修正的 Perdew Burke Ernzerhof（RPBE）交换关联泛函无法重现实验观察到的 NH-O 吸附物-吸附物相互作用和 NH 在 Pt(111)和（2×2）O/Pt(111)上的结合能，这表明对于这两个体系，色散相互作用都很重要。
