Modification of Metal Nanoparticles with TiO2 and Metal−Support Interaction in Photodeposition

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1、RESEARCHARTICLEpubs.acs.org/acscatalysisModificationofMetalNanoparticleswithTiO2andMetal-SupportInteractioninPhotodeposition††,‡†,†JunyaOhyama,AkiraYamamoto,KentaroTeramura,*TetsuyaShishido,andTsunehiroTanaka*†DepartmentofMolecularEngineering,GraduateSchoolofEngin

2、eering,KyotoUniversity,Kyoto615-8510,Japan‡KyotoUniversityPioneeringResearchUnitforNextGeneration,KyotoUniversity,Kyoto615-8510,JapanbSSupportingInformationABSTRACT:Rh,Pt,andAumetalsphotodepositedonTiO2withananatasephase(M-TiO2(p),M:Rh,Pt,Au)werestudiedusingtrans-

3、missionelectronmicroscopy(TEM),scanningtransmissionelectronmicroscopy,energydispersiveX-ray(EDX)analysis,X-rayabsorptionfinestructure(XAFS)spectroscopy,X-rayphotoelectronspectroscopy(XPS),andXPSdepthprofileanalysis.TheTEMimagesofRh-TiO2-(p)andPt-TiO2(p)didnotclearly

4、showthegrainboundaryofmetalparticles,althoughtheRhandPtspeciesofRh-TiO2(p)andPt-TiO2-(p)wereobservedbyEDXanalysistoshowthemetalparticles10-20nminsize.TheseresultssuggestthatthephotodepositedRhandPtmetalpar-ticleshaveadisorganizedstructure,whichisalsosupportedbyext

5、endedXAFSspectralanalysis.Itisspeculatedthatastrongmetal-supportinter-actiontakesplaceinthecaseofRhandPt,resultinginthedisorganizedstructure.InthecaseofAu,however,metalparticleswithawell-organizedandsphericalstructurewereobserved,indicatingthatAudoesnotstronglyint

6、eractwithTiO2.TheXPSanalysesrevealedthatthesurfaceofmetalparticlesofM-TiO2(p)receivedelectronsfromTiO2.TheXPSdepthprofileanalysissuggeststhatthemetalparticlesaremodifiedwithTiO2.TiO2-δgeneratedbythephotoirradiationofTiO2cancausethemodificationandthedisorganizedstruct

7、ureofRhandPtmetalparticles.KEYWORDS:photodeposition,Rh-TiO2,Pt-TiO2,Au-TiO2,M-TiO,photoirradiation,EM,EDX,XAFS,XPS,depthanalysis’INTRODUCTIONTheinteractionbetweenthesupportandthemetalinasupported-metalcatalystplaysanimportantroleinthecatalyticPhotodepositionhasbee

8、nusedtorecovernoblemetals,to10,11reaction.ThetreatmentofgroupVIIInoblemetals(e.g.,Pt,removemetalcationsfromaqueouseffluents,andtopreparemetal-supportedcat