Steric Hindrance of NH3 Diffusion on Pt(111) by Co-Adsorbed O-Atoms

A detailed velocity-resolved kinetics study of NH3 thermal desorption rates from p(2 x 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...

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Detalles Bibliográficos
Autores: Borodin, Dmitriy, Galparsoro Larraza, Oihana, Rahinov, Igor, Fingerhut, Jan, Schwarzer, Michael, Horandl, Stefan, Auerbach, Daniel J., Kandratsenka, Alexander, Schwarzer, Dirk, Kitsopoulos, Theofanis N., Wodtke, Alec M.
Tipo de recurso: artículo
Fecha de publicación:2022
País:España
Institución:Universidad del País Vasco
Repositorio:Addi. Archivo Digital para la Docencia y la Investigación
OAI Identifier:oai:addi.ehu.eus:10810/59324
Acceso en línea:http://hdl.handle.net/10810/59324
Access Level:acceso abierto
Palabra clave:total energy calculations
ultrasoft pseudopotentials
wave
transition
adsorption
Descripción
Sumario:A detailed velocity-resolved kinetics study of NH3 thermal desorption rates from p(2 x 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 x 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 x 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 x 2) O/Pt(111), which indicates the importance of dispersion interactions for both systems.

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