Durable PROX catalyst based on gold nanoparticles and hydrophobic silica

Handle URI:
http://hdl.handle.net/10754/594734
Title:
Durable PROX catalyst based on gold nanoparticles and hydrophobic silica
Authors:
Laveille, Paco; Guillois, Kevin; Tuel, Alain; Petit, Corine; Basset, Jean-Marie ( 0000-0003-3166-8882 ) ; Caps, Valerie
Abstract:
3 nm gold nanoparticles (Au NP) obtained by direct chemical reduction of AuPPh3Cl in the presence of methyl-terminated silica exhibit superior durability for low temperature CO oxidation in the presence of hydrogen (PROX). The activity of hydrophobic Au/SiO2-R972 indeed appears much more stable with time-on-stream than those of the OH-terminated, hydrophilic Au/TiO2 and Au/Al2O3 catalysts, with similar Au NP size. This enhanced stability is attributed to the peculiar catalyst surface of Au/SiO2-R972. Not only may the support hydrophobicity concentrate and facilitate reactant adsorption and product desorption over Au NP, but methyl-terminated SiO2-R972 likely also inhibits carbonatation of the Au/support interface. Hence, at a temperature at which H2/H2O “cleaning” of the carbonate-contaminated Au/Al2O3 and Au/TiO2 surface is inefficient (< 100°C), passivated Au/SiO2-R972 displays much more stable PROX activity. Besides, the virtual absence of surface hydroxyl groups, which provide sites for water formation in H2/O2 atmospheres, can also account for the improved PROX selectivity (>85%) observed over Au/SiO2-R972. This new example, of CO oxidation activity of gold nanoparticles dispersed over a hydrophobic, “inert” support, clearly emphasizes the role of hydrogen as a promoter for the gold-catalyzed oxidation of CO at low temperature. Unlike support-mediated oxygen activation, hydrogen-only mediated oxygen activation takes full advantage of the hydrophobic surface, which is much more resistant against CO2 and thus remains free of poisonous carbonate species, as compared with hydroxyl-terminated catalysts. Hence, although the absence of surface hydroxyl groups prevents the hydrophobic Au/SiO2-R972 catalyst to reach the state-of-the-art activities initially displayed by Au/TiO2 and Au/Al2O3, it brings long-term stability with time-on-stream and superior selectivity, which opens up promising perspectives in the development of viable PROX catalysts based on gold.
KAUST Department:
KAUST Catalysis Center (KCC)
Citation:
Durable PROX catalyst based on gold nanoparticles and hydrophobic silica 2016 Chem. Commun.
Publisher:
Royal Society of Chemistry (RSC)
Journal:
Chem. Commun.
Issue Date:
20-Jan-2016
DOI:
10.1039/C5CC09561A
Type:
Article
ISSN:
1359-7345; 1364-548X
Additional Links:
http://pubs.rsc.org/en/Content/ArticleLanding/2016/CC/C5CC09561A
Appears in Collections:
Articles; KAUST Catalysis Center (KCC)

Full metadata record

DC FieldValue Language
dc.contributor.authorLaveille, Pacoen
dc.contributor.authorGuillois, Kevinen
dc.contributor.authorTuel, Alainen
dc.contributor.authorPetit, Corineen
dc.contributor.authorBasset, Jean-Marieen
dc.contributor.authorCaps, Valerieen
dc.date.accessioned2016-01-24T10:25:34Zen
dc.date.available2016-01-24T10:25:34Zen
dc.date.issued2016-01-20en
dc.identifier.citationDurable PROX catalyst based on gold nanoparticles and hydrophobic silica 2016 Chem. Commun.en
dc.identifier.issn1359-7345en
dc.identifier.issn1364-548Xen
dc.identifier.doi10.1039/C5CC09561Aen
dc.identifier.urihttp://hdl.handle.net/10754/594734en
dc.description.abstract3 nm gold nanoparticles (Au NP) obtained by direct chemical reduction of AuPPh3Cl in the presence of methyl-terminated silica exhibit superior durability for low temperature CO oxidation in the presence of hydrogen (PROX). The activity of hydrophobic Au/SiO2-R972 indeed appears much more stable with time-on-stream than those of the OH-terminated, hydrophilic Au/TiO2 and Au/Al2O3 catalysts, with similar Au NP size. This enhanced stability is attributed to the peculiar catalyst surface of Au/SiO2-R972. Not only may the support hydrophobicity concentrate and facilitate reactant adsorption and product desorption over Au NP, but methyl-terminated SiO2-R972 likely also inhibits carbonatation of the Au/support interface. Hence, at a temperature at which H2/H2O “cleaning” of the carbonate-contaminated Au/Al2O3 and Au/TiO2 surface is inefficient (< 100°C), passivated Au/SiO2-R972 displays much more stable PROX activity. Besides, the virtual absence of surface hydroxyl groups, which provide sites for water formation in H2/O2 atmospheres, can also account for the improved PROX selectivity (>85%) observed over Au/SiO2-R972. This new example, of CO oxidation activity of gold nanoparticles dispersed over a hydrophobic, “inert” support, clearly emphasizes the role of hydrogen as a promoter for the gold-catalyzed oxidation of CO at low temperature. Unlike support-mediated oxygen activation, hydrogen-only mediated oxygen activation takes full advantage of the hydrophobic surface, which is much more resistant against CO2 and thus remains free of poisonous carbonate species, as compared with hydroxyl-terminated catalysts. Hence, although the absence of surface hydroxyl groups prevents the hydrophobic Au/SiO2-R972 catalyst to reach the state-of-the-art activities initially displayed by Au/TiO2 and Au/Al2O3, it brings long-term stability with time-on-stream and superior selectivity, which opens up promising perspectives in the development of viable PROX catalysts based on gold.en
dc.language.isoenen
dc.publisherRoyal Society of Chemistry (RSC)en
dc.relation.urlhttp://pubs.rsc.org/en/Content/ArticleLanding/2016/CC/C5CC09561Aen
dc.rightsArchived with thanks to Chem. Commun.en
dc.titleDurable PROX catalyst based on gold nanoparticles and hydrophobic silicaen
dc.typeArticleen
dc.contributor.departmentKAUST Catalysis Center (KCC)en
dc.identifier.journalChem. Commun.en
dc.eprint.versionPost-printen
dc.contributor.institutionIRCELYON (Institut de recherches sur la catalyse et l'environnement de Lyon), University of Lyon / CNRS UMR 5256, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex, Franceen
dc.contributor.institutionICPEES (Institut de Chimie et Procédés pour l'Energie, l'Environnement et la Santé), Université de Strasbourg / CNRS UMR 7515, 25 rue Becquerel, 67087 Strasbourg Cedex 2, Franceen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorLaveille, Pacoen
kaust.authorBasset, Jean-Marieen
kaust.authorCaps, Valerieen
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