Abstract
A detailed velocity-resolved kinetics study of NH3 thermal desorption rates from p(2 × 2) O/Pt(111) is presented. We find a large reduction in the NH3 desorption rate due to adsorption of O-atoms on Pt(111). A physical model describing the interactions between adsorbed NH3 and O-atoms explains these observations. By fitting the model to the derived desorption rate constants, we find an NH3 stabilization on p(2 × 2) O/Pt(111) of 0.147-0.014+0.023 eV compared to Pt(111) and a rotational barrier of 0.084-0.022+0.049 eV, which is not present on Pt(111). The model also quantitatively predicts the steric hindrance of NH3 diffusion on Pt(111) due to co-adsorbed O-atoms. The derived diffusion barrier of NH3 on p(2 × 2) O/Pt(111) is 1.10-0.13+0.22 eV, which is 0.39-0.14+0.22 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 NH3-O adsorbate-adsorbate interactions and NH3 binding energies at Pt(111) and p(2 × 2) O/Pt(111), which indicates the importance of dispersion interactions for both systems.
Original language | English |
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Pages (from-to) | 21791-21799 |
Number of pages | 9 |
Journal | Journal of the American Chemical Society |
Volume | 144 |
Issue number | 47 |
DOIs | |
State | Published - 30 Nov 2022 |
Bibliographical note
Funding Information:D.B., J.F., A.K., and T.N.K. acknowledge support from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. [833404]). O.G. acknowledges financial support by the Spanish Ministerio de Ciencia e Innovación [Grant no. PID2019-107396GB-I00/AEI/10.13039/501100011033]. I.R. gratefully acknowledges the support by Israel Science Foundation, ISF (grant No. 2187/19), and by the Open University of Israel Research Authority (grant No. 31044). M.S. thanks the BENCh graduate school, funded by the DFG (389479699/GRK2455).
Funding Information:
Open access funded by Max Planck Society.
Publisher Copyright:
© 2022 The Authors. Published by American Chemical Society.
Keywords
- Adsorption
- Diffusion
- Kinetics