Adsorption and Oxidation of CO on Ceria Nanoparticles Exposing Single-Atom Pd and Ag: A DFT Modelling

Various CO<sub>x</sub> species formed upon the adsorption and oxidation of CO on palladium and silver single atoms supported on a model ceria nanoparticle (NP) have been studied using density functional calculations. For both metals M, the ceria-supported MCO<sub>x</sub> moie...

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Autores principales:	Vladimir A. Nasluzov, Elena A. Ivanova-Shor, Aleksey M. Shor, Svetlana S. Laletina, Konstantin M. Neyman
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	CeO<sub>2</sub>-based nanomaterials density functional calculations single-atom catalysts structure reactivity Technology T Electrical engineering. Electronics. Nuclear engineering TK1-9971 Engineering (General). Civil engineering (General) TA1-2040 Microscopy QH201-278.5 Descriptive and experimental mechanics QC120-168.85
Acceso en línea:	https://doaj.org/article/fa9ff7b775fe4054bfc70192e9fdee46
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spelling	oai:doaj.org-article:fa9ff7b775fe4054bfc70192e9fdee462021-11-25T18:14:29ZAdsorption and Oxidation of CO on Ceria Nanoparticles Exposing Single-Atom Pd and Ag: A DFT Modelling10.3390/ma142268881996-1944https://doaj.org/article/fa9ff7b775fe4054bfc70192e9fdee462021-11-01T00:00:00Zhttps://www.mdpi.com/1996-1944/14/22/6888https://doaj.org/toc/1996-1944Various CO<sub>x</sub> species formed upon the adsorption and oxidation of CO on palladium and silver single atoms supported on a model ceria nanoparticle (NP) have been studied using density functional calculations. For both metals M, the ceria-supported MCO<sub>x</sub> moieties are found to be stabilised in the order MCO < MCO<sub>2</sub> < MCO<sub>3</sub>, similar to the trend for CO<sub>x</sub> species adsorbed on M-free ceria NP. Nevertheless, the characteristics of the palladium and silver intermediates are different. Very weak CO adsorption and the small exothermicity of the CO to CO<sub>2</sub> transformation are found for O<sub>4</sub>Pd site of the Pd/Ce<sub>21</sub>O<sub>42</sub> model featuring a square-planar coordination of the Pd<sup>2+</sup> cation. The removal of one O atom and formation of the O<sub>3</sub>Pd site resulted in a notable strengthening of CO adsorption and increased the exothermicity of the CO to CO<sub>2</sub> reaction. For the analogous ceria models with atomic Ag instead of atomic Pd, these two energies became twice as small in magnitude and basically independent of the presence of an O vacancy near the Ag atom. CO<sub>2</sub>-species are strongly bound in palladium carboxylate complexes, whereas the CO<sub>2</sub> molecule easily desorbs from oxide-supported AgCO<sub>2</sub> moieties. Opposite to metal-free ceria particle, the formation of neither PdCO<sub>3</sub> nor AgCO<sub>3</sub> carbonate intermediates before CO<sub>2</sub> desorption is predicted. Overall, CO oxidation is concluded to be more favourable at Ag centres atomically dispersed on ceria nanostructures than at the corresponding Pd centres. Calculated vibrational fingerprints of surface CO<sub>x</sub> moieties allow us to distinguish between CO adsorption on bare ceria NP (blue frequency shifts) and ceria-supported metal atoms (red frequency shifts). However, discrimination between the CO<sub>2</sub> and CO<sub>3</sub><sup>2−</sup> species anchored to M-containing and bare ceria particles based solely on vibrational spectroscopy seems problematic. This computational modelling study provides guidance for the knowledge-driven design of more efficient ceria-based single-atom catalysts for the environmentally important CO oxidation reaction.Vladimir A. NasluzovElena A. Ivanova-ShorAleksey M. ShorSvetlana S. LaletinaKonstantin M. NeymanMDPI AGarticleCeO<sub>2</sub>-based nanomaterialsdensity functional calculationssingle-atom catalystsstructurereactivityTechnologyTElectrical engineering. Electronics. Nuclear engineeringTK1-9971Engineering (General). Civil engineering (General)TA1-2040MicroscopyQH201-278.5Descriptive and experimental mechanicsQC120-168.85ENMaterials, Vol 14, Iss 6888, p 6888 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	CeO<sub>2</sub>-based nanomaterials density functional calculations single-atom catalysts structure reactivity Technology T Electrical engineering. Electronics. Nuclear engineering TK1-9971 Engineering (General). Civil engineering (General) TA1-2040 Microscopy QH201-278.5 Descriptive and experimental mechanics QC120-168.85
spellingShingle	CeO<sub>2</sub>-based nanomaterials density functional calculations single-atom catalysts structure reactivity Technology T Electrical engineering. Electronics. Nuclear engineering TK1-9971 Engineering (General). Civil engineering (General) TA1-2040 Microscopy QH201-278.5 Descriptive and experimental mechanics QC120-168.85 Vladimir A. Nasluzov Elena A. Ivanova-Shor Aleksey M. Shor Svetlana S. Laletina Konstantin M. Neyman Adsorption and Oxidation of CO on Ceria Nanoparticles Exposing Single-Atom Pd and Ag: A DFT Modelling
description	Various CO<sub>x</sub> species formed upon the adsorption and oxidation of CO on palladium and silver single atoms supported on a model ceria nanoparticle (NP) have been studied using density functional calculations. For both metals M, the ceria-supported MCO<sub>x</sub> moieties are found to be stabilised in the order MCO < MCO<sub>2</sub> < MCO<sub>3</sub>, similar to the trend for CO<sub>x</sub> species adsorbed on M-free ceria NP. Nevertheless, the characteristics of the palladium and silver intermediates are different. Very weak CO adsorption and the small exothermicity of the CO to CO<sub>2</sub> transformation are found for O<sub>4</sub>Pd site of the Pd/Ce<sub>21</sub>O<sub>42</sub> model featuring a square-planar coordination of the Pd<sup>2+</sup> cation. The removal of one O atom and formation of the O<sub>3</sub>Pd site resulted in a notable strengthening of CO adsorption and increased the exothermicity of the CO to CO<sub>2</sub> reaction. For the analogous ceria models with atomic Ag instead of atomic Pd, these two energies became twice as small in magnitude and basically independent of the presence of an O vacancy near the Ag atom. CO<sub>2</sub>-species are strongly bound in palladium carboxylate complexes, whereas the CO<sub>2</sub> molecule easily desorbs from oxide-supported AgCO<sub>2</sub> moieties. Opposite to metal-free ceria particle, the formation of neither PdCO<sub>3</sub> nor AgCO<sub>3</sub> carbonate intermediates before CO<sub>2</sub> desorption is predicted. Overall, CO oxidation is concluded to be more favourable at Ag centres atomically dispersed on ceria nanostructures than at the corresponding Pd centres. Calculated vibrational fingerprints of surface CO<sub>x</sub> moieties allow us to distinguish between CO adsorption on bare ceria NP (blue frequency shifts) and ceria-supported metal atoms (red frequency shifts). However, discrimination between the CO<sub>2</sub> and CO<sub>3</sub><sup>2−</sup> species anchored to M-containing and bare ceria particles based solely on vibrational spectroscopy seems problematic. This computational modelling study provides guidance for the knowledge-driven design of more efficient ceria-based single-atom catalysts for the environmentally important CO oxidation reaction.
format	article
author	Vladimir A. Nasluzov Elena A. Ivanova-Shor Aleksey M. Shor Svetlana S. Laletina Konstantin M. Neyman
author_facet	Vladimir A. Nasluzov Elena A. Ivanova-Shor Aleksey M. Shor Svetlana S. Laletina Konstantin M. Neyman
author_sort	Vladimir A. Nasluzov
title	Adsorption and Oxidation of CO on Ceria Nanoparticles Exposing Single-Atom Pd and Ag: A DFT Modelling
title_short	Adsorption and Oxidation of CO on Ceria Nanoparticles Exposing Single-Atom Pd and Ag: A DFT Modelling
title_full	Adsorption and Oxidation of CO on Ceria Nanoparticles Exposing Single-Atom Pd and Ag: A DFT Modelling
title_fullStr	Adsorption and Oxidation of CO on Ceria Nanoparticles Exposing Single-Atom Pd and Ag: A DFT Modelling
title_full_unstemmed	Adsorption and Oxidation of CO on Ceria Nanoparticles Exposing Single-Atom Pd and Ag: A DFT Modelling
title_sort	adsorption and oxidation of co on ceria nanoparticles exposing single-atom pd and ag: a dft modelling
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/fa9ff7b775fe4054bfc70192e9fdee46
work_keys_str_mv	AT vladimiranasluzov adsorptionandoxidationofcoonceriananoparticlesexposingsingleatompdandagadftmodelling AT elenaaivanovashor adsorptionandoxidationofcoonceriananoparticlesexposingsingleatompdandagadftmodelling AT alekseymshor adsorptionandoxidationofcoonceriananoparticlesexposingsingleatompdandagadftmodelling AT svetlanaslaletina adsorptionandoxidationofcoonceriananoparticlesexposingsingleatompdandagadftmodelling AT konstantinmneyman adsorptionandoxidationofcoonceriananoparticlesexposingsingleatompdandagadftmodelling
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Adsorption and Oxidation of CO on Ceria Nanoparticles Exposing Single-Atom Pd and Ag: A DFT Modelling

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