留学美国签证研究计划模板大全.docx

留学美国签证研究计划模板大全.docx

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留学美国签证研究计划模板大全

留学美国签证研究计划模板大全

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Descriptionsoftheresearchplan

Title:

Synthesis,FormationMechanism,andPropertiesofDifferentMetal/MetalNanostructures

Keywords:

Multi-ShellNanostructures,IonicLiquids,Electrochemistry,Multi-Functionality,

PorousMetalMaterials,Low-Dimensionality,GreenChemistryObjectives:

Thisprogramistodevelopanovelmethodforfabricatingheterogeneousoralloyeddifferentmetal/metallow-dimensionalnanostructures,forexample,multi-shellorporousAg-Aunanowires,nanorods,andnanocubesusinganionicliquidasboththesolventandshape-inducingtemplate.Synthesisofionicliquids（ILs）withdifferentalkylchainsandfunctionalgroups,aswellastheformationofdifferentmetal/metalnanostructureswithnewpropertiesareinvolvedinthisresearchplan.Alloyedorheterogeneousmulti-shellnanostructuresaregeneratedbyutilizingelectrochemical（electroless）depositionorasimplegalvanicreplacementreactioninILs.Bycontrollingthesize,shape,composition,crystalstructureandsurfacepropertiesofthesestructures,itenablesusnotonlytouncovertheirintrinsicproperties,butexploittheirformationmechanisminILsmedia,aswellastheirapplicationsincatalysis,surface-enhancedRamanscattering（SERS）,sensors,porouselectrodes,etc.Thisgreenchemistryprocessalsomaybeextendedtosynthesizeotherorganicandinorganicnanostructureswithnovelproperties,morphologyandcomplexform.State-of-the-art

Metalnanostructureshavenumerousapplicationsasnanoscalebuildingblocks,templates,andcomponentsinchemicalandbiologicalsensors,aswellaselectronic/opticaldevices,duetotheirinterestingoptical,catalyticandelectricalpropertiesthatdependstronglyonbothsizeandshape.Overthepastdecade,impressiveprogresshasbeenmadetowardsthefairlygoodshapeandsizecontrolofmetalnanostructures[1][2].Fornoblemetals,moreemphasisisplacedontuningthenovelshape-dependentpropertiesofthesenanostructuresincontrasttothesize-dependency.Avarietyofmetallicbuildingblockswithuniquepropertieshavebeensynthesizedincludingcubes[3][4],prisms[5],disks[6],andhollownanostructures[7].Currentlytheinterestsmigratetothesynthesisandapplicationofmorecomplexstructureswithdifferentmetals,suchasmulti-shellandheterogeneousnanostructureshavingnewproperties[8][9],couplingaconceptionforoptimizingpreparativestrategiesinanenvironmentallybenignsystem[10].Therefore,besidescreatingnovelnanostructureswithuniqueproperties,aproblemarisingfromtheutilizationofvolatileorpoisonousorganicsolventsandadditivesisofmuchconcerninviewofcleanertechnologythroughoutbothindustryandacademia.

Mostofthecurrentshapeselectivesynthesisofmetalnanostructuresthattheiropticalpropertiesaremarkedlyaffectedbytheirshapeandaspectratioarecenteredeitheronasolidsubstratebyphysicalmethodsorinaqueousororganicmediathroughchemicalprocedures[2].Forinstance,complexandhighlyregularcrystallinesilverinukshukarchitecturescanbeproduceddirectlyonagermaniumsurfacethroughasimplegalvanicdisplacementreactionthatonlythreeingredientswererequired:

silvernitrate,water,andgermanium[11].Despitetheseadvancements,however,limitedreportshavebeenreportedonhowtheparticlemorphologyanddimensionalitycouldberegulatedbytheutilizationofILs[12].

Recently,environmentallybenignroom-temperatureionicliquids（RTILs）havereceivedincreasingattentionworldwideduetotheirfavorablepropertiesincludingexcellentthermalandchemicalstability,goodsolubilitycharacteristics,highionicconductivity,negligiblevaporpressure,nonflammability,relativelylowviscosity,andawideelectrochemicalwindow.Thisclassoffluidmaterialscontainscomplicatedmolecularinteractionssuchasionicinteractions,hydrogenbonding,л-лinteractions,andamphiphilicpolarization,renderingvariousmolecularstructuresfrommerelylocalordernessuptomacroscopicthermotropicorlyotropicliquidcrystallinephases[13].Theseadvantagesmakethemactivelybeingemployedasgreensolventsfororganicchemicalreactions,extractionandseparationtechnologies,catalysis,solarcells,andelectrochemicalapplications[14][15].

IncontrasttotremendousgrowthinR&Donapplicationofionicliquidstochemicalprocessing,theuseofRTILsininorganicsynthesisisstillinitsinfancy.Therehavebeenonlyafewreportsontheshape-and-dimensioncontrolledformation,byusingRTILs,ofhollowTiO2microspheres[16]andnanowiresofpalladium[17],goldnanosheets[12],telluriumnanowires[18],flower-likeZnOnanostructures[19],andCuClnanoplatelets[20].Sofar,alloyedmetalstructures,eithersphericalnanoparticlesornanocompositefilms,havebeengeneratedinRTILsusingelectrochemicaldepositionofnanocrystallinemetalssuchasAl-Fe,andAl-Mnalloysondifferentsubstrates[21].However,formationofmulti-shellorhollownanostructuresbycontrollingboththeshapeanddimensioninRTILshasnotyetappearedinliterature,especiallyusinganelectrochemicalapproach.Itisthereforeproposedinthisprogramthatanewroutetoopticallyorcatalyticallytunethepropertiesofcomplexmetal/metalnanostructuresthroughthecontrolofshapeanisotropyandsurfacemorphologyisestablishedinRTILsusingagreenchemistryapproach.ThereasonswechooseRTILsasreactionmediaarenotonlyintheviewofenvironmentprotection,butintheconsiderationoftheirdiversiformmolecularstructures,whichcouldbeusedasshape-inducingtemplatesforthesynthesisofnewnanostructures.ItisveryunlikelythatILswillentirelyreplaceorganicsolventsoraqueoussystemsorgasphaseprocessesforthefabricationofinorganicmatter.Nevertheless,ionicliquidswithdifferentfunctionalgroupsmayprovideameanstofabricatenanostructuresthatarenototherwiseavailable.Theapplicanthasaccumulatedgoodbackgroundsinshape-controlledsynthesisandcharacterizationofmetalandsemiconductorlow-dimensionalnanostructureswithuniqueopticalproperties.AseriesofapproacheshavebeenusedtofabricateAg-SiO2,andAg-TiO2core-shellnanostructuresandAg-SiO2-TiO2nanocompositefilms.DuringthePh.Dprogram,novelsoftsolandpolymer-assistedmethodshavebeendevelopedtoformmetalandsemiconductornanorodsandwires,suchassilverandgoldnanowires,CdSandZnSnanowiresandrods,aswellasanisotropicmetalnanocrystals,forexample,silvernanoprisms,goldnanocubes,nanodisks,andsoon[22][23].Atthesametime,tuningtheopticalpropertiesthroughtheinteractionofnanostructureswithfemtosecondlaserpulsestocontrolthesize,shapeordimensioninnanometerregimehasalsobeeninvestigated[24].AsfortheinstitutiontowhichtheapplicantisapplyingandthegroupofProfessorXXXXXXX,equipmentsincludingTEM,SEM,UV-Vis-NIRabsorptionspectrometerandotheremissionspectrometer（static,time-resolvedandtemperaturedependent）,aswellasthegroup’sexcellentresearchexperienceinsemiconductorandmetalnanomaterials[25][26]provideasoundfoundationfortheimplementationofthisresearchplan,probablyresultinginnotonlyabetterunderstandingoftheutilizationofRTILsinnanochemistryandelectrochemistry,butcreatingnewnanostructures,suchasmicroporousAg/Aumulti-shellnanowireswithpromisingapplicationsinSERS,catalysis,etc.

Amultidisciplinaryapproachandtheplannedactivities

Amultidisciplinaryapproachisdesignedinthisproposalthroughintegratingorganicsynthesis,electrochemistry,materialsscienceandoptoelectronics,aimingtofabricatedifferentmetal/metalmulti-shellheterogeneousnanostructuresincludingnanocubes,nanorings,nanoplates,nanowiresandnanotubes.Thisresearchplancoversthreeaspects:

ThefirstoneistocreatenovelstructuresthroughthereductionofdifferentmetalprecursorsinRTILsusingreducingagentsorelectrosyntheticprocesses.Thesecondistoproduceporouslowdimensionalmetalnanostructuresbyetchingwithspecificsolutions（e.g.concentratedammoniaorhydrochloricacid）orusinggalvanicdisplacementreactionandelectrochemicalanodization.Thethirdistoinvestigatetheformationmechanismandpropertiesofthesenanomaterials.

1.Synthesisofmetalnanostructureswithtailoredmorphology

2.Formationofporouslowdimensionalnanostructures.

3.Propertiesofdifferentmetal/metalnanostructures.

4.Apossibleextensionofthisresearchplan

Anotherimportantdirectionistofabricatemagnetic/semiconductingcore-shellnanocrystals,suchasFe3O4/CdSe,ordyemoleculecomplexedrareearthmetalstoformGd（BPy）/CdSeusingRTILsasreactionmedia.Thesenanocrystalscontainingbothfluorescenceandmagneticresonanceembeddedinsilicananoparticlescanbeusedasprobesforthestudyofbiologicalmaterials,especiallyinbio-imaging.Themagnetic/semiconductingcore-shellcomplexnanocrystalsofferdistinctadvantagesoverconventionaldye-molecules,magneticresonanceimaging（MRI）,andsimplexsemiconductornanocrystalsnotonlyinthattheyemitmultiplecolorsoflightandcanbeusedtolabelandmeasureseveralbiologicalmarkerssimultaneously,butinthecapabilitytotargetmoleculeswithagoodspatialresolution.

Timeschedulefortheplan

May1,2006-July1,2006

TwomonthsGermanlearninginaGoetheInstitute

July1,2006-Oct.31,2006

1.Discussiononthedetailedresearchplanandthepreparationofmaterials

2.Synthesisandcharacterizationoflow-dimensionalnanostructuresinRTILs

3.Publishing1papers

4.Attendingoneinternationalconventiononnanostructuresandapplications

Nov.1,2007-Mar.31,2007

1.Furtherimprovementoftheopticalandcat