相關課程材料合成化學4-3metal synthesis color

Chapter4-2:Synthesisofmetaland.2Theory:nucleation-seed-4.2.3Chemicalreduction(synthesisofAuandbi-metallic4.2.4Electrochemical.64.2.7ChemicalVapor PhysicalVaporDeposition(Vacuum4.2.9Case“金并不難，看你“金并不難，看你怎樣去還原““” 做還原劑，送你多少電子也與你穩(wěn)定地在一“最外層電子越多越容易得到電子，正如易掙錢。所以 充滿 Nanomaterialsisnotnew…nanoscienceChi’enLungDynasty(1736-

TEMof4nmAu–lightpinkTEMof30nmAu–deepredGoldnanosphereswithincreasingdiameterBulk4122537Opticalpropertiesofmetalnanoparticlesdependon4122537ParticlefunctionalizationcanbedoneontheVisibleopticalchangesMichael1791-09-22–1867-08-25(agedKnownfor:PortraitbyHenryWilliamPickersgill,ca.

PhysicsandRoyalFaraday'slawofFaradayeffectFaradaycageFaradayconstantFaradaycupFaraday'slawsofelectrolysisFaradayparadoxFaradayrotatorFaraday-efficiencyeffectFaradaywaveFaradayLines“Faraday'sGold”andGoldGold

Incontrasttoallothermetals,“Goldhasbeenbeatenintoleavessofineasto partiallytransparent,—notinconsequenceofanycracks,holes,orfissures,butbytheshiningoflightthroughitssubstance”(Faraday1853,p.Gold“Faraday'sGold”andGoldLecturegivenonJune12th1858,entitled'OntherelationofGoldtoM.Faraday,'TheBakerianlecture:experimentalrelationsofgold(andothermetals)tolight',PhilosophicalTransactionsoftheRoyalSocietyofLondon,Vol.147(1847),145-181Faradaydiscoveredthathecouldturnthepreparationbluebyaddingcertainsalts.Goldsolsalsocoagulatedwhensaltswereadded,althoughthiscouldbepreventedbytheadditionofgelatin.5HAuCl43P12H2O5Au20HCl3H36Au3CHO315OH6Au6CO10H

SlidethatFaradayusedinhislectureongoldsols,in1858En2h2FluorescenceofCdSeQ-dotsunderUV

ParticlesizeSemiconductornanoparticles(1-20nm,quantumdots,Qparticles)haveastructuralarrangementsimilartobulkmaterials,butverydifferentphysicalproperties(optical,En2h2ParticlesizeSizetunablefluorescenceemissionfromCdSe/ZnScores AuCoord.Chem.Rev.249(2005)1870-Thecolorofgoldrodsandtherespectivemicrographs.Thecolorchangestake ceforverysmallchangesinmeanaspectratio.TheoryofTwowaystopreparemetalMetalnanoparticlescanbepreparedsubdivisionofbulkmetals(physicalmethod);thegrowthofparticlesstartingfrommetalatomsobtainedfrommolecularorionicprecursors(chemicalmethod).②ismoresuitablethan①tosmallanduniform②,controloftheatomaggregationisthemostimportantsteptocontrolthesizeanduniformityofthemetal

NewJ.Chem.,1998,22,1179- Bottom-up(Y.N.Xiaetal.,Angew.Chem.Int.Ed.2009,48,60–SynthesisofMetalSimpleChemistryComplexofvariousshapesNucleation positionLaMer2)Nuclei+atoms?seedsseeds*+nuclei?seedsV.K.LaMer,R.H.Dinegar,J.Am.Chem.Soc.1950,72,4847.Au13,Au20,Pt38,M55(M=Au,Pt,andRh),Pt309,Pd1415,andPd2057havebeenReactionpathwaysthatleadtofccmetalnanocrystalshavingdifferentshapes.

Rr100/r100:growthratealong100r111:growthratealong111EvolutionfromnucleitoForfcc,surface{100}=4(/a2),{110}=4.24(/a2),{111}=∴{111}<{100}<∴Asingle-crystalseedshouldtakeanoctahedraltetrahedralshapeinorder izetheexpression{111}facetsandminimizethetotalsurfaceBothBothshapes,however,havelargersurfaceareasthanacubeofthesamevolume.Asaresult,single-crystalseedsareexpectedtoexistastruncatedoctahedrons(orWulffpolyhedrons)enclosedbyamixof{111}and{100}facets.Thisshapehasanearlysphericalprofileandthusthesmallestsurfaceareatominimizethetotalinterfacial energy. EvolutionfromnucleitoKineticte-likeseeds)canbeachievedInpractice,structurescharacteristicte-likeseeds)canbeachievedInpractice,structurescharacteristicofkineticallypositionsubstantiallyslowingdownprecursorusingaweakreducing syntheses synthesescouplingthereductiontoanoxidationprocess,couplingthereductiontoanoxidationprocess,takingadvantageofOstwaldte-likeEvolutionfromnucleitoOxidativesingle-crystalvs.twinnedseedscanbefurthermanipulatedthroughtheuseofoxidativeetching,inwhichzero-valentmetalatomsareoxidizedbacktoions.Combinationoftheligand+O2canresultinapowerfuletchantforboththenucleiandseeds.,Defectzonesintwinnedseedsaremuchhigherinenergyrelativetothesingle-crystalregionsandthusaremostsusceptibletoanoxidativeenvironment,withtheiratomsbeingattackedbytheetchant,oxidized,anddissolvedintothesolution.AgNO3PVP今

1010244Inair,0.06mM

B.Wileyetal.,NanoLett.2004,4,EvolutionfromseedstoSurfaceSurface

Harris,P.J.F.Nature792?794[Pt(NH3)4]Cl2supportedonAl2O3in-situgenerated:CO,S(S-poisoning),addedpurposely:PVP,Br-,CH3(CH2)15N+(CH3)3Br-(orCTAB),etc.EvolutionfromseedstoShapeEvolutionduringCrystalGrowth:3-DOvergrowthOvergrowthprocessofAgnanocrystals,inwhichAgatomsarecontinuouslydepositedontothe{100}facetsofaAgnanocubetoeventuallyresultinanoctahedronenclosedby{111}facets.In3-D,ifthefastgrowingedgescorrespondtothecornersofatruncatedcube,thefinalcrystalshapewillthenbeacubefacetedbytheslowgrowing nes.Incontrast,ifin3-Dthefastgrowingedgescorrespondtothefacesofatruncatedcube,thefinalcrystalshapewillbeanoctahedronfacetedbythoseslowgrowingChemicalreduction

M=Au,Pt,Ag,Pd,Co,Fe,Reductant=H2,Citrate,Borohydride(ABH4),N2H4?H2O,N2H4?2HCl,Shipway,A.N.;Katz,E.;Willner,I. .2000,1,18-Functionalized XXXXXXYYYYYYYYYYXXX

XXXSyntheticApproachesforMetal(andMetalPositivelychargemetalsalt,MetalcentersofSolvents(dependsonthenatureofthePolarorganic-polarorganicReducingagent(determinedbythenatureofthemetalHydridicReducingorganics,e.g.Alkalimetals,e.g.K(AlCl3+3K-.Al+3KClindryManyothers(e.g.SyntheticApproachesforMetalandRoleofstabilizers:Stabilizing agents/passivatingpreventuncontrollablegrowthofpreventparticlecontrolgrowthcontrolparticleallowparticlesolubilityinvariousCommonOrganicThiols(thioethanol,thioglycerol,mercaptoethylamine,phosphates(HPO42-Polyoxoanions:P2W15Nb3O629-,SiW9Nb3O407-,Mo6O192-W ControlfactorsinchemicalreductionStirringRateSizeRateofReductantStirringFreshFilteredSolutionHayat,M.A.,Ed.,ColloidalGold: Applications;AcademicPress:SanDiego,1989;Vol1.HowtopreparemonodisperseHomogeneousnucleationoccursviaastepwisesequencebimolecularadditionsuntilanucleusofcriticalsizeisNucleationfromsupersaturatedDiffusion-ControlledSn+

LaMerLaMeretal.J.Am.Chem.Soc.1950,72,HighlymonodispersenanoparticlesareformediftheprocessesHighlymonodispersenanoparticlesareformediftheprocessesofnucleationandgrowthcanbesuccessfullyNucleationprocessmustbeGrowthprocessmustbeNanoparticleGrowthinArrestedprecipitation(抑制性沉淀Precipitationunderstarvingconditions:alargenumberofnucleationcentersareformedbyvigorousmixingofthereactantsolutions.Ifconcentrationgrowthiskeptsmall,nucleigrowthisstoppedduetolackofmaterial.OswaldThegrowthmechanismwheresmallparticlesdissolve,andareconsumedbylargerparticles.Asaresulttheaveragenanoparticlesizeincreaseswithtimeandtheparticleconcentrationdecreases.Asparticlesincreaseinsize,solubilitydecreases.ParticlesParticleshadtobeprotectedfromOswaldRipeningbyA1-SchematicProcedureforCluster?????????????

electron

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Addphasee.g.tetraoctylbromide(TOAB)

Standardelectrode2H++2e-? E°=B(OH)3+7H++8e-?BH4-+ E°=-N2H4?2H2O?N2H5++

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+

+N2+5H++4e-?N2H5

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+ E°=-ExamplesofmetalparticlesfromchemicalreductioninaqueoussolutionsSDS=sodiumdodecylsulfateExamplesofmetalparticlesfromchemicalreductionin -aqueoussolutionsOthercommonEx.PreparationofAunanoparticlesbychemicalreductionReducingAu3+

AuParametersAffectingParticleGrowth/Shape/ Typeof agent/stabilizers:e.g. Concentrationofthe pHvalueofthe Durationofheat

CTAB=cetyltrimethylammoniumbromideSDS=sodiumdodecylAunanoparticlespreparedinthepresenceofJ.J.Phys.Chem.B.2001,105, teSoft 納納Hard te

Pt

PVP Synthesisof++(

160-180VariousStagesofWire10 2040 60SilverNanowireswith~40Example:Aunanorodssynthesizedbyseed-mediatedchemicalreductionAunanorodssynthesizedbyseed-mediatedchemicalreductionCitrateCitrateisasaagentagenttoparticleFromFrom3.5-4nmsphericalseedscangrowoutto20-30nmwideandupto600longnanorods,andnoAunanorodssynthesizedbyseed-mediatedchemicalreduction:aspectratio(L/w)

Twofactorstodetermineseedsize;2)tailDependenceofgoldnanorodaspectratioonthetaillengthofthecationicsurfactantCnTAB(allalkyltrimethylammoniumGrowthmechanismsurfactant-directedmetalnanorodgrowthnardensityofatomsofFCCstructure{111}:{100}:{110}: model”:theformationofthebilayerofCnTAB(squiggles)onthenanorod(blackrectangle)surfacemayassistnanorodformationasmoregoldion(blackdots)isintroduced.Thepreferentialbindingisbasedonsterics-theAuatomspacingonthesidefacesismorecomparabletothesizeoftheCTA+headgroupthantheclose-packed{111}faceofgold,whichisattheendsofthenanorods.(CCHnote:CouldalsobeduetoenergyEffectofdifferent Ag teandselectiveJinR.etal.Nature2003,425,JinR.etal.Science2001,294,AherneD.etal.Adv.Funct.Mater.2008,18,Effectofdifferent Ag Effectofdifferent AgZeng,J.etal.J.Am.Soc.2010,132,Effectofdifferent Ag teandselectiveZengJ.etal.Angew.Chem.Int.Ed.50,Effectofdifferent Ag teandselectiveSynthesisofbimetallic (bysuccessive

+ M2++

MixedAlloy(byco-M1++M2++Toshima,N.;Yonezawa,T.NewJournalofChemistry1998,1179-However,therearecomplicatede.g.inAu-Pdsystem:a)AufollowedbyPd今monometallicAu+Pd;b)PdfollowedbyAu今Pd-Aubutnotcore-s ;c)co-reductionofAuandPd今Au@Pd(core-s );d)largePdcorefollowedbyAu今Pd@Au(core-s SynthesisofFePtalloynanoparticleinhightemperaturesolutionsoleic

J.AM.CHEM.SOC.2006,128,7132-Adv.Mater.2006,18,SonochemicalApproachesforParticleUltrasonic:>‘a(chǎn)rea’+

Rectified ’-Acousticcavitation空穴效應Supercriticalfluid:Step

BubbleexpandswhensurroundingmediumexperiencesBubblecollapseswhensurroundingmediumexperiencesBubblecollapseleadstoextremetemperatures(5,000K),and(100atm)withintheStepSolventorsolutemoleculespresentwithinthebubbles undertheseextremeconditionsandgeneratehighlyreactiveFormationofHighlyReactiveDependingontheliquidmedium,sonicationleadstogenerationofoxidizingandreducingInaqueous H?+ +H

Insoluteslikealcohols,sonicationleadstosecondaryRCH2OH+H?(OH?)RCHOH?+M+

RCHOH?+H2(H2O)M+RCHO+H+ExamplesofMetalNanoparticlesPreparedbyAgnanoparticlespreparedinaqueoussolutionat1 +H?

H?+ J.J.Phys.Chem.1987,91,Aunanoparticlespreparedby

ROH

Au+LangmuirLangmuir2002,18,7831-Electrochemical

→Metn++nCathode:Metn++ne-+stabilizer Metbulk+stabilizer→Reetz,M.T.;Winter,M.;Breinbauer,R.;Thomas,T.-A.;Vogel,W.Chem.Eur.J.2001,7,ElectrochemicalreductiontoprepareAu teCuorAgbyCoord.Chem.Rev.2491870-(aandb)Analuminamembrane.(c)Successivestagesduringtheformationofgoldnanorodsviathetem temethod.(d)Goldnanorodsobtainedbythe temethod.Limitationofthe temethod:verylowyield.Sinceonlymonolayersofareprepared,evenmilligramamountsofrodsarearduoustoElectrochemicalreductiontoprepareAuSonoelectrochemical Electrolytecontains:hexadecyltrimethylammoniumbromide(C16TAB)+asmallamountofamuchmorehydrophobiccationicsurfactant,tetradodecylammoniumbromide(TC12AB)(actsasarod-inducingcosurfactant).C16TAB:asthesupportingelectrolyte+asthestabilizerforthenanoparticles(topreventtheirfurtheraggregation).

VA,powersupply;G,glasswareelectrochemicalcell;T,teflonspacer;S,electrodeholder;U,ultrasoniccleaner;A,anode;C,cathode.Beforetheelectrolysis,appropriateamountsofacetoneandcyclohexaneareaddedintotheelectrolyticsolution.AcetoneisusedforlooseningthemicellarframeworkC16TABmicelles,andcyclohexaneisnecessaryforenhancingtheformationofelongatedrod-likeC16TABmicellesWangetal.,Langmuir15(1999)電化學研磨 納米金屬粒子(“Top-Tarasconetal.,J.Electrochem.Soc.148(2001)電化學研磨 納米金屬粒CuO/Licell(CR2032)

CuO＋Linano-Cu+

Chem.Mater.Chem.Mater.17(2005)5242-J.Phys.Chem.C112(2008)4176-Electrochem.Commun.6(2004)33-J.AlloyComp.391(2005)212-216;J.Electroceram.15(2005)109-電化學研磨 納米金屬粒電化學研磨 納米金屬粒ParticlesizeParticlesize0

StartingCuOparticlesize: Current電化學研磨 納米金屬粒CuOCuO＋Linano-Cu+Afterdifferent Cu2O-Li2OfilmbyESD ting化學鍍，無電（電）鍍Doesn’trequireacontinuousconductivepath tingontotingcanbedonestraight sticsandotherGenerally2mechanismsforelectrolessdeposition:(1) cementreactionor(2)autocatalyticdeposition.Galvanicdis cementreliesonrelativepositionsinelectrochemicalseries.AutocatalyticrequirestheemploymentofacatalyticmetalkickstartandaidsustainmentoftheGalvanic ting ting（浸鍍Galvanic ting: Inanimmersiontingbath,theelectronsare dbythebasemetal,andeffectivelythebasemetalisthereducingagent.Asthebasemetaldonateselectronstothemetalbeingted,thebasemetalitselfgoesintosolution,whichiswhythisisalsocalledarecementreaction.Thekeycharacteristicsoftheimmersion tingbathisthatitisselflimiting,whichmeansthatoncethebasemetal,copper,inthecaseofaPCB(i.e.PrintedCircuitBoard),iscovered,thetingThiscanresultinaverythin,dense, -porouscoating,thatisveryeconomical,fromabaththatisextremelystable,andimpossibletodropout,unlessitisdesired,forwastetreatment.Galvanic ting: 化學鍍錫機φ，錫的標準）4(NH2)2CS+2Cu-2e→Sn2++2e→ ting:silveringofFlatglasssubstrateisimmersedinstannous(tin)chlorideandrinsed–asmalldispersionoftinionsremainonthesurfaceThesubstrateisthenimmersedinasolutioncontainingsilvernitrateandotherchemicalse.g.,ammonia,hydrochloricacid,isopropanol(IPA).Asmallamountofformaldehydeisaddedtothesolutionandthereductionoccursofsilverionsinthenitratetosilvermetalonthesurfacewherethetinispresent.Potentials

Iron-Tin-HydrogenIodineGold

Nickel-Lead-CopperSilver ting:AutocatalyticprocessrequiresthepresenceofaPalladium(Pd)isapopular tinum(Pt)andnoblemetalshavealsobeenInelectrolesscopper,palladiumisgenerallyusedtokickstartthereductionofcopperionstocoppermetalfromionsinCopperitselfisalsocatalytic(althoughmuchlessactiveHencethetermAutocatalytic–oncepalladiumisusedup,thecopperitselfactsasthecatalysttosustaintheprocess–depositionslowsdownthough. ting:InitialdepositionisProcessdoeshoweverslowdown afteracertainthicknessisreached–e.g.~100mforAg,~1mforCu.MetalionsinsolutionmayhavetobereplenishedforitremainInanelectrolesscopperbaththeformaldehydeisthereducingagent.InElectrolessNickelitiseitherHypophosphite,orDimethylAmine二甲胺硼

次磷酸Commonelectrolessmetalsare:copper,silverand tingsolutionsgenerallyincludeorganicsubstancesmetal-ioncomplexingagentsandOfelectroless tingmethods,the iscommonlyusedto sticobjectscosmetically,andtheethylenediaminetetraacetic-acid(EDTA)bathto teprinted-circuitboards.Complexingagentsareessentialtoproduce Typicalcopperloadingis2to3gperlitreofElectrolessdepositionofAu:thin化學鍍薄金工藝配]Au（以KAu(CN)2入 12次磷酸 氯化 氯化 2L溫 時 9ElectrolessdepositionofAu:thick化學鍍厚金金（以KAu(CN)2形式加入）（g/L） 偏亞硫酸 次磷酸 44NanometalsfromthermolysisandThermolysisofe.g.transitionmetalcarbonylsunderaninertatmospheremayproducemetalcolloids.e.g.thermolysisofFe(CO)5-+Fe+5COinanorganicproduces“ferrofluids”ofmetallicironnanoparticles(8.5Ni,Co,FeandCunanoparticleshavebeenpreparedfromM(OOCH)x-+M+xCO2+x/2H2(orM+x/2CO+x/2CO2+x/2OrfromthePhotolysis,e.g.photochemical positionofsilverhalide(AgCl)nanocrystals.4.2.8Chemicalvapordeposition2Cu3Cl3(g)+3H2(g)?6Cu(s)+6HClCo(CO)4(g)?Co(s)+4CO4.2.9VacuumVacuum熱蒸鍍法:熱蒸鍍法:粉末樣品,無基底

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