Lead oxide-modified TiO2 photocatalyst: tuning light absorption and charge carrier separation by lead oxidation state

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dc.contributor.authorIwaszuk, Anna
dc.contributor.authorNolan, Michael
dc.contributor.funderHigher Education Authorityen
dc.contributor.funderScience Foundation Irelanden
dc.contributor.funderEuropean Commissionen
dc.contributor.funderSeventh Framework Programme
dc.contributor.funderPartnership for Advanced Computing in Europe AISBL
dc.date.accessioned2016-07-22T09:06:20Z
dc.date.available2016-07-22T09:06:20Z
dc.date.issued2013-05-09
dc.date.updated2014-04-08T12:39:13Z
dc.description.abstractModification of TiO2 with metal oxide nanoclusters such as FeOx, NiOx has been shown to be a promising approach to the design of new photocatalysts with visible light absorption and improved electron–hole separation. To study further the factors that determine the photocatalytic properties of structures of this type, we present in this paper a first principles density functional theory (DFT) investigation of TiO2 rutile(110) and anatase(001) modified with PbO and PbO2 nanoclusters, with Pb2+ and Pb4+ oxidation states. This allows us to unravel the effect of the Pb oxidation state on the photocatalytic properties of PbOx-modified TiO2. The nanoclusters adsorb strongly at all TiO2 surfaces, creating new Pb–O and Ti–O interfacial bonds. Modification with PbO and PbO2 nanoclusters introduces new states in the original band gap of rutile and anatase. However the oxidation state of Pb has a dramatic impact on the nature of the modifications of the band edges of TiO2 and on the electron–hole separation mechanism. PbO nanocluster modification leads to an upwards shift of the valence band which reduces the band gap and upon photoexcitation results in hole localisation on the PbO nanocluster and electron localisation on the surface. By contrast, for PbO2 nanocluster modification the hole will be localised on the TiO2 surface and the electron on the nanocluster, thus giving rise to two different band gap reduction and electron–hole separation mechanisms. We find no crystal structure sensitivity, with both rutile and anatase surfaces showing similar properties upon modification with PbOx. In summary the photocatalytic properties of heterostructures of TiO2 with oxide nanoclusters can be tuned by oxidation state of the modifying metal oxide, with the possibility of a reduced band gap causing visible light activation and a reduction in charge carrier recombination.en
dc.description.sponsorshipHigher Education Authority and Science Foundation Ireland (Irish Centre for High End Computing); European Commission (European Union FP7 Research Infrastructures Program PRACE, through the DECI-8 program, 10 contracts RI-261557 and RI-283493; European Union, COST Action CM1104 “Reducible Oxide Chemistry, Structure and Functions”)en
dc.description.statusPeer revieweden
dc.description.versionAccepted Versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationIwaszuk, A. and Nolan, M. (2013) 'Lead oxide-modified TiO2 photocatalyst: tuning light absorption and charge carrier separation by lead oxidation state', Catalysis Science & Technology, 3(8), pp. 2000-2008. http://dx.doi.org/10.1039/C3CY00194Fen
dc.identifier.doi10.1039/c3cy00194f
dc.identifier.endpage2008en
dc.identifier.issn2044-4753
dc.identifier.issn2044-4761
dc.identifier.issued8en
dc.identifier.journaltitleCatalysis Science & Technologyen
dc.identifier.startpage2000en
dc.identifier.urihttps://hdl.handle.net/10468/2923
dc.identifier.volume3en
dc.language.isoenen
dc.publisherRoyal Society of Chemistryen
dc.relation.projectinfo:eu-repo/grantAgreement/SFI/SFI Starting Investigator Research Grant (SIRG)/09/SIRG/I1620/IE/EMOIN: Engineering Metal Oxide Interfaces For Renewable Energy Photocatalysis/
dc.rights© The Royal Society of Chemistry 2013. This is the Accepted Manuscript version of a published work that appeared in final form in Catalysis Science & Technology, http://dx.doi.org/10.1039/C3CY00194Fen
dc.subjectDensity functional theoryen
dc.subjectDoped-TiO2en
dc.subjectTitanium(IV) Dioxideen
dc.subjectElectronic structureen
dc.subjectTransition metalen
dc.subjectOxygen vacanciesen
dc.subjectAnatase TiO2en
dc.subjectSurfaceen
dc.subjectIrradationen
dc.titleLead oxide-modified TiO2 photocatalyst: tuning light absorption and charge carrier separation by lead oxidation stateen
dc.typeArticle (peer-reviewed)en
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