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Hydrogenating activity of Pt/zeolite catalysts focusing acid support and metal dispersion influence

2015-09-05Journal article Restricted access
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dc.contributor.authorMendes, Pedro S. F.
dc.contributor.authorLapisardi, Grégory
dc.contributor.authorBouchy, Christophe
dc.contributor.authorRivallan, Mickaël
dc.contributor.authorSilva, João
dc.contributor.authorRibeiro, M. Filipa
dc.date.accessioned2016-03-11T14:48:43Z
dc.date.available2016-03-11T14:48:43Z
dc.date.issued2015-09-05
dc.description.abstractToluene hydrogenation was studied over catalysts based on Pt supported on large pore zeolites (HUSY and HBEA) with different metal/acid ratios. Acidity of zeolites was assessed by pyridine adsorption followed by FTIR showing only small changes before and after Pt introduction. Metal dispersion was determined by H2–O2 titration and verified by a linear correlation with the intensity of Pt0–CO band obtained by in situ FTIR. It was also observed that the electronic properties of Pt0 clusters were similar for the different catalysts. Catalytic tests showed rapid catalyst deactivation with an activity loss of 80–95% after 60 min of reaction. The turnover frequency of fresh catalysts depended both on metal dispersion and the support. For the same support, it changed by a 1.7-fold (HBEA) and 4.0-fold (HUSY) showing that toluene hydrogenation is structure-sensitive, i.e. hydrogenating activity is not a unique function of accessible metal. This was proposed to be due to the contribution to the overall activity of the hydrogenation of adsorbed toluene on acid sites via hydrogen spillover. Taking into account the role of zeolite acidity, the catalysts series were compared by the activity per total adsorbing sites which was observed to increase steadily with nPt/(nPt + nA). An increase of the accessible Pt atoms leads to an increase on the amount of spilled over hydrogen available in acid sites therefore increasing the overall activity. Pt/HBEA catalysts were found to be more active per total adsorbing site than Pt/HUSY which is proposed to be due to an augmentation in the efficiency of spilled over hydrogen diffusion related to the proximity between Pt clusters and acid sites. The intervention of Lewis acid sites in a greater extent than that measured by pyridine adsorption may also contribute to this higher activity of Pt/HBEA catalysts. These results reinforce the importance of model reactions as a closer perspective to the relevant catalyst properties in reaction conditions.pt_PT
dc.identifier.citationMENDES, Pedro S. F.; [et al.] - Hydrogenating activity of Pt/zeolite catalysts focusing acid support and metal dispersion influence. Applied Catalysis A-General. ISSN.0926-860X. Vol. 504, SI (2015), pp. 17-28pt_PT
dc.identifier.doi10.1016/j.apcata.2015.03.027pt_PT
dc.identifier.issn0926-860X
dc.identifier.issn1873-3875
dc.identifier.urihttp://hdl.handle.net/10400.21/5836
dc.language.isoengpt_PT
dc.peerreviewedyespt_PT
dc.publisherElsevier Science BVpt_PT
dc.relation.ispartofseriesSI;
dc.relation.publisherversionhttp://www.sciencedirect.com/science/article/pii/S0926860X15002136pt_PT
dc.subjectPlatinumpt_PT
dc.subjectHUSYpt_PT
dc.subjectHBEApt_PT
dc.subjectToluene hydrogenationpt_PT
dc.subjectFTIRpt_PT
dc.titleHydrogenating activity of Pt/zeolite catalysts focusing acid support and metal dispersion influencept_PT
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage28pt_PT
oaire.citation.startPage17pt_PT
oaire.citation.volume504pt_PT
person.familyNameSilva
person.givenNameJoão Miguel Alves da
person.identifierfWmw7kEAAAAJ
person.identifier.ciencia-id3D1F-BD3A-4A9D
person.identifier.orcid0000-0003-1244-6483
person.identifier.scopus-author-id16317291000
rcaap.rightsclosedAccesspt_PT
rcaap.typearticlept_PT
relation.isAuthorOfPublication36449517-d0f7-4619-aae3-81af776b82fd
relation.isAuthorOfPublication.latestForDiscovery36449517-d0f7-4619-aae3-81af776b82fd

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