CO oxidation promoted by a subnano Pt 4 cluster deposited on the anatase a-TiO 2 (101) surface has been investigated by means of DFT + U calculations. The focus of the study is on the role of supported Pt 4 in favoring the formation of an oxygen vacancy at interface sites between Pt 4 and the TiO 2 surface, a key step in CO oxidation reactions according to a Mars–van Krevelen mechanism. The motivation is to compare this reaction mechanism with other processes described in the literature for Pt clusters on anatase TiO 2 where the reaction involves O 2 dissociation at the surface of the metal particle or its activation at the metal/oxide interface. A significant decrease in the energetic cost to remove a lattice oxygen is observed at the interface sites between Pt 4 and TiO 2 , compared to regular sites. This favors the CO oxidation processes by a direct interaction of the CO molecule with a lattice oxygen, with formation of CO 2 and an oxygen vacancy. The processes is slightly endothermic, and occurs with barriers comparable, or even lower, than found for the case of Au nanoparticles supported on the same a-TiO 2 (101) surface. The next step consists in the re-oxidation of the support. The calculations show that the O 2 molecule adsorbs strongly on the reduced catalyst, dissociates with one O atom that recreates the stoichiometric surface, and the other that remains adsorbed on the surface, ready to react with a second CO molecule. Graphical Abstract: [Figure not available: see fulltext.].

Thang, H., Pacchioni, G. (2019). CO Oxidation Promoted by a Pt 4 /TiO 2 Catalyst: Role of Lattice Oxygen at the Metal/Oxide Interface. CATALYSIS LETTERS, 149(2), 390-398 [10.1007/s10562-018-2610-2].

CO Oxidation Promoted by a Pt 4 /TiO 2 Catalyst: Role of Lattice Oxygen at the Metal/Oxide Interface

Thang, HV
;
Pacchioni, G
2019

Abstract

CO oxidation promoted by a subnano Pt 4 cluster deposited on the anatase a-TiO 2 (101) surface has been investigated by means of DFT + U calculations. The focus of the study is on the role of supported Pt 4 in favoring the formation of an oxygen vacancy at interface sites between Pt 4 and the TiO 2 surface, a key step in CO oxidation reactions according to a Mars–van Krevelen mechanism. The motivation is to compare this reaction mechanism with other processes described in the literature for Pt clusters on anatase TiO 2 where the reaction involves O 2 dissociation at the surface of the metal particle or its activation at the metal/oxide interface. A significant decrease in the energetic cost to remove a lattice oxygen is observed at the interface sites between Pt 4 and TiO 2 , compared to regular sites. This favors the CO oxidation processes by a direct interaction of the CO molecule with a lattice oxygen, with formation of CO 2 and an oxygen vacancy. The processes is slightly endothermic, and occurs with barriers comparable, or even lower, than found for the case of Au nanoparticles supported on the same a-TiO 2 (101) surface. The next step consists in the re-oxidation of the support. The calculations show that the O 2 molecule adsorbs strongly on the reduced catalyst, dissociates with one O atom that recreates the stoichiometric surface, and the other that remains adsorbed on the surface, ready to react with a second CO molecule. Graphical Abstract: [Figure not available: see fulltext.].
Articolo in rivista - Articolo scientifico
CO oxidation; Density functional theory; Heterogeneous catalysts; Mars–van Krevelen mechanism; Oxygen vacancy; Pt/TiO ; 2; TiO ; 2; anatase ;
CO oxidation; Density functional theory; Heterogeneous catalysts; Mars–van Krevelen mechanism; Oxygen vacancy; Pt/TiO ; 2; TiO ; 2; anatase
English
2019
149
2
390
398
none
Thang, H., Pacchioni, G. (2019). CO Oxidation Promoted by a Pt 4 /TiO 2 Catalyst: Role of Lattice Oxygen at the Metal/Oxide Interface. CATALYSIS LETTERS, 149(2), 390-398 [10.1007/s10562-018-2610-2].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/260122
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