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Water adsorption on MO2 (M = Ti, Ru, and Ir) surfaces. Importance of octahedral distortion and cooperative effects
González, Danilo (Universitat Autònoma de Barcelona. Departament de Química)
Heras-Domingo, Javier (Universitat Autònoma de Barcelona. Departament de Química)
Pantaleone, Stefano (Universitat Autònoma de Barcelona. Departament de Química)
Rimola, Albert (Universitat Autònoma de Barcelona. Departament de Química)
Rodríguez Santiago, Luis (Universitat Autònoma de Barcelona. Departament de Química)
Solans Monfort, Xavier (Universitat Autònoma de Barcelona. Departament de Química)
Sodupe Roure, Mariona (Universitat Autònoma de Barcelona. Departament de Química)

Data: 2019
Resum: Understanding metal oxide MO2 (M = Ti, Ru, and Ir)-water interfaces is essential to assess the catalytic behavior of these materials. The present study analyzes the H2O-MO2 interactions at the most abundant (110) and (011) surfaces, at two different water coverages: isolated water molecules and full monolayer, by means of Perdew-Burke-Ernzerhof-D2 static calculations and ab initio molecular dynamics (AIMD) simulations. Results indicate that adsorption preferably occurs in its molecular form on (110)-TiO2 and in its dissociative form on (110)-RuO2 and (110)-IrO2. The opposite trend is observed at the (011) facet. This different behavior is related to the kind of octahedral distortion observed in the bulk of these materials (tetragonal elongation for TiO2 and tetragonal compression for RuO2 and IrO2) and to the different nature of the vacant sites created, axial on (110) and equatorial on (011). For the monolayer, additional effects such as cooperative H-bond interactions and cooperative adsorption come into play in determining the degree of deprotonation. For TiO2, AIMD indicates that the water monolayer is fully undissociated at both (110) and (011) surfaces, whereas for RuO2, water monolayer exhibits a 50% dissociation, the formation of H3O2 - motifs being essential. Finally, on (110)-IrO2, the main monolayer configuration is the fully dissociated one, whereas on (011)-IrO2, it exhibits a degree of dissociation that ranges between 50 and 75%. Overall, the present study shows that the degree of water dissociation results from a delicate balance between the H2O-MO2 intrinsic interaction and cooperative hydrogen bonding and adsorption effects.
Ajuts: Ministerio de Economía y Competitividad CTQ2017-89132-P
Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-1323
Drets: Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. Creative Commons
Llengua: Anglès
Document: Article ; recerca ; Versió publicada
Matèria: Oxides ; Adsorption ; Molecules ; Monolayers ; Deprotonation
Publicat a: ACS omega, Vol. 4, Issue 2 (February 2019) , p. 2989-2999, ISSN 2470-1343

DOI: 10.1021/acsomega.8b03350
PMID: 31459524


11 p, 2.8 MB

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 Registre creat el 2020-07-06, darrera modificació el 2023-05-25



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