掃描電化學(xué)顯微鏡-瑞士萬通學(xué)習(xí)報告PPT課件

.,1,ScanningElectrochemicalMicroscopy掃描電化學(xué)顯微鏡,掃描電化學(xué)顯微鏡學(xué)習(xí)總結(jié)張富緯2016.9.17,.,2,Asmallprobeisscannedinshortdistanceoverasamplesurfaceandacharacteristicpropertyofthesampleisdetected.Interactionofprobeandsample!其原理是在樣品短距離的表面上，通過探針與樣品的相互作用并檢測到樣品的特征屬性。掃描探針技術(shù)有STM,AFM,SNOM,SECMScanningelectrochemicalmicroscopy(SECM)istheonlytechniqueabletodetect(electro-)chemicalreactions.SECM是唯一一種能夠檢測（電）化學(xué)反應(yīng)的掃描探針技術(shù)。Resolutiondependsonthetipsize!,SECMClassificationSECM歸類于掃描探針技術(shù)Scanningprobetechniques:,3,.,3,BasicSetup下圖是整個儀器的形貌,4,.,4,4,這是與SECM連用的電化學(xué)工作站,這是SECM的工作池也就是放樣品的區(qū)域（長寬高大概為2*2*1cm）,SECM目前只能在小樣品（1cm左右），平面上做一些基礎(chǔ)性研究使用。,.,5,ImagingModes,5,SECM的這些工作模式基底都是不通電的，這是原來理解上的一個誤區(qū)。這個誤區(qū)在下面反饋模式中的正反饋中給本人和萬通中國的人都造成了誤解。正反饋是由于基底為導(dǎo)體由于導(dǎo)體與探針之間的相互作用導(dǎo)致了電流的增大。其關(guān)于電流密度的掃描是通過一定電鍍時間的間隔下對被鍍件表面進(jìn)行掃描通過哪里沉積的多少來實現(xiàn)的。,.,6,ImagingModesNegativeFeedback,Areversibleredoxspeciesisrequired!,6,.,7,ImagingModesPositiveFeedback,7,由于基底不通電所以檢測基底活性是SECM都是采用的可溶解的氧化還原電對（如Fe3+/Fe2+）。,.,8,FeedbackMode-MeasurementConditions,CalculatedapproachcurveswithRG=10accordingtoJ.L.Amphlettetal.,J.Phys.Chem.B102(1998),9946,8,.,9,FeedbackMode,9,.,10,ArrayScanforSurfaceMapping,x,y,datapoint,individuallineofarrayscan,10,.,11,FeedbackMode,Visualizationofelectrochemicalactivitydistributiononasamplesurface.,11,.,12,FeedbackMode-Example,Ru3+Ru2+,itip,-400mV,12,.,13,FeedbackMode-ExampleDifferencesinlocalelectrochemicalactivitye.g.duetosurfaceimpurities.,GeneralgoalofSECMstudiesisthedeterminationoftheelectron-transferkineticsatthesamplesurface!,13,.,14,Generator/CollectorMode(GCMode),14,.,15,Generator/CollectorMode-Example,15,.,16,ComparisonFeedbackandGCMode,5mMRu(NH3)63-in100mMKCl,RE:Ag/AgCl(3MKCl),forGC:WE1:2ndbandEsample=-400mV,WE2:25mPttip,Ru2+,Ru3+,0mV,Ru3+,Ru2+,Ru3+,Ru2+,-400mV,16,.,17,ComparisonFeedbackandGCMode,5mMRu(NH3)63-in100mMKCl,RE:Ag/AgCl(3MKCl),forGC:WE1:2ndbandEsample=-400mV,WE2:25mPttip,+sensitivitylateralresolution(diffusionprofiles)timedependency,+lateralresolutionhighbackgroundcurrentredoxmediatorrequired,17,.,18,PracticalTrainingSECM,18,Fe2+Fe3+,500mV,.,19,LocalexperimentsduetomobileelectrochemicalcellStandardEC(OCPdetection,polarizationcurvesetc.)possibleOnlysmallareaofsamplesisincontactwithelectrolyte,exchangeofsolutionpriortoeachnewgridpoint,RE,CE,ElectrolyteWE,19,對于我們公司這種大且形狀復(fù)雜的產(chǎn)品，Thomas給出了一下Cell的解決方案不過這是一種全新的技術(shù)，其液滴口直徑也不超過1mm，基本無工業(yè)化應(yīng)用價值。,ScanningDropletCellSDC,.,20,ScanningDropletCellOptionSDC,LocalexperimentsduetomobileelectrochemicalcellStandardEC(OCPdetection,polarizationcurvesetc.)possibleOnlysmallareaofsamplesisincontactwithelectrolytePhotoelectrochemistry,RE,CE,Electrolyteinlet20,.,21,SECMApplicationsSECM的應(yīng)用領(lǐng)域,.,22,Application,SECMisalwaysuseablewhenthelocaleffectsdeterminethepropertyofthewholematerial(globalappearance).SECM主要是通過研究材料的局部反應(yīng)來判斷材料的整體性能。,2,.,23,FieldsofApplication,3,腐蝕,催化劑,燃料電池,表面修飾,與我們公司關(guān)聯(lián)性較大的主要就是腐蝕不過其主要是用于單層涂層的耐蝕性研究。對于電鍍產(chǎn)品而言此功能通過電化學(xué)工作站的阻抗分析也可以實現(xiàn)。,.,24,ReactivityonStainlessSteels304and316,J.Izquierdoetal.,ElectrochimicaActa134(2014),167,StainlessSteel316,StainlessSteel304,0.5h,4h,7.5h,24h,0.5h,3h,4,Distributionofiron(II)ions0.25MHCl(GC-Mode),.,25,O2,O2,O2,O2,O2,CorrosionofSteelOxygenCompetitionE,iiT,EConsumptionofOxygenistracedVariationofGC-modeJ.J.Santanaetal.,Electrochim.Acta55(2010),44885,.,26,CorrosionProtectiveCoatings,R.G.Duarteetal.,Prog.Org.Coat.74(2012),365,PVCPlastisolcoatednickel,foilsand0.5mM,ferrocene-methanol.,Insulatoras,samplesurfaceTopography,6,.,27,CorrosionProtectiveCoatings,J.Izquierdoetal.,Prog.Org.Coat.74(2012),526,2-mercaptobenzimidazole,SECMimagerecordedinmeasuringsolutionof,0.1MNa2SO4+1mM,ferrocenemethanol,7,.,28,E.Martinez-Lombardiaetal.,Electrochim.Acta116(2014),89,5mMferrocenemethanol,Corrosion-CopperImagewithpassivelayerEffectsduetocrystallographicorientationsofcopperImageafterremovalofpassivelayer,8,.,29,DissimilarWeld,J.Jayarajetal.,J.Adv.Microsc.Res.7(2012),214,Tipreactionat1.5V:,HNO3+2H+2e-HNO2+H2O,9,.,30,Self-healingCoatings,A.Pilbthetal.,Prog.Org.Coat.75(2012),480,DetectionofFe2+,DetectionofO2,Microcapsuleswithlinseedoilmixed,intoepoxyresincoating.,10,.,31,Catalysis,11,.,32,PtonCsupport(E-tek),VulcanXC-72R,PrintexL6,CatalysisFuelCellsOxygenReductionReactionORRinalkalinesolution,effectofcarbonsupportH2O2detection,M.H.M.T.Assumpoetal.,Carbon49(2011),284212,.,33,ElectrocatalyticActivityofCarbonFiber,Investigationofasinglestrandofcarbonfiber.,3mM-methylferrocenemethanolinphosphatebuffer,PseudofirstorderrateconstantviaapproachcurvesV.S.Joshietal.,J.Phys.Chem.C116(2012),970313,.,34,MembraneTransport,Transportphenomenainchannels/membranes/pores,14,.,35,DiffusionthroughMembranesforGasSensors,M.Nebeletal.,Electrochim.Acta55(2010),7923,15,.,36,LifeSciences-BiodegradableMaterial,M.D.Peredaetal.,ActaBiomater.6(2010),1772,16,.,37,MaterialScienceReducedGrapheneOxideonFabrics,J.Molinaetal.,Appl.Surf.Sci.279(2013),46,17,.,38,Biosensors,Biosensorcharacterization,18,.,39,GCandRC-SECMforBiosensors,I.Morkvenaite-Vilkoncieneetal.,RSCAdv.4(2014),50064.,19,.,40,CellularActivity,Releaseorconsumption,20,.,41,RespirationActivity,d,t=15ms,Topography,M.Nebeletal.Angew.Chem.Int.Ed.52(2013)633521,.,42,Intra-andExtracellularRedoxProcessesYeastCell,I.Morkvenaite-Vilkoncieneetal.,SensorsandActuatorsB:Chemical228(2016),200,22,.,43,SECMAdvancedDetectionModesSECM前沿的檢測方法,.,44,AC-SECM阻抗-SECM聯(lián)用技術(shù),Alladvantagesoffrequency,dependentresponse,NoredoxmediatornecessaryDilutedsolutionpossible,Impedancespectraateachpointofthescannedgrid,measuredatthetipinclosedistancetothesamplesurface.,2,.,45,AC-SECM,RE,CE,non-conductive,B.BallesterosKatemann,A.Schulte,E.J.Calvo,M.Koudelka-Hep,W.Schuhmann,Electrochem.Commun.(2002),4134,A.S.Baranski,P.M.Diakowski,J.SolidStateElectrochem.(2004),8,683K.Eckhard,T.Erichsen,M.Stratmann,W.Schuhmann,Chem.Eur.J.(2008),14,3968,RCt,Cdl,RS,RCt,Cdl,RS,RSt,RSs,RP1,RP2,CP1,CP2,conductivesample,RctCdlRsRP,=,chargetransferresistancedoublelayercapacitancesolutionresistancepolarizationresistance(sample),3,.,46,AC-SECM,RE,CE,RE,CE,Cdl,RS,RCt,Cdl,RS,RSt,RSs,RP1,RP2,CP1,CP2,constant,Nofaradayprozess,A.S.Baranski,P.M.Diakowski,J.SolidStateElectrochem.(2004),8,683K.Eckhard,T.Erichsen,M.Stratmann,W.Schuhmann,Chem.Eur.J.(2008),14,3968,NofaradayprozessRCt,non-conductiveRSincreasesduringapproach,conductivesamplealternativepaththroughsample,4,.,47,Z/Z,AC-SECM,1mMKCl,RE:Ag/AgCl,Ampl.10mV,RCt,Cdl,RS,RSt,RSP,RP1,RP2,CP1shortcut,CP2,RctCdlRsRP,=,chargetransferresistancedoublelayercapacitancesolutionresistancepolarizationresistance(sample),0,8,0,1,32,Glass,0.5kHz,GlassPlatinumPlatinum,6kHZ0.5kHz6kHz,4L=d/r,5,.,48,ComparisonLEISandAC-SECMEWE,5-electrodeconfigurationLEIS:GlobalACperturbationatsample,measurementoflocalACcurrentdensitytocalculatelocalimpedance.,3-electrodeconfigurationAC-SECM:ACperturbationdirectlyattipelectrodeandinteractionunderneathmeasured,usesSECMtips(muchsmallertipsresolution)6,.,49,HighresolutionimaginginSECM成像技術(shù),.,50,ResolutioninSECM,Tipsize(ratioofthesizeoftipandstructure)Distancebetweendatapoints(stepsize)Workingdistance(contrast),DetectionmodeandRGvalueoftip,*Ratioofoverallelectroderadiustotheradiusoftheactivetipsurface,2,.,51,Fe2+Fe3+,itip,500mV,3,.,52,ResolutioninSECMEffectofTipSize,5mMFe(CN)64-in100mMKCl,RE:Ag/AgCl(3MKCl),Etip=+500mV,Feedbackmode,25mPttipIncrements:x=12.5m,y=25mWorkingdistance:25m,10mPttipIncrements:x=5m,y=10mWorkingdistance:10m,4,.,53,ResolutioninSECMEffectofTipSize,Interactionarea,dependsontipsize,Signalaveragedovertipsize,5,.,54,ResolutioninSECMEffectofTipSize,25mPttipIncrements:x=12.5m,y=10mWorkingdistance:12.5m5mMFe(CN)64-in100mMKCl,RE:Ag/AgCl(3MKCl),Etip=+500mV,10mPttipIncrements:x=5m,y=10mWorkingdistance:5m,6,.,55,ResolutioninSECM-TheParameterStepWidth,d,r,Fastexperiment,nolossofinformation.Max.ofinformationandwellresolvedgraphs.NoadditionalinformationBUTincreaseoftheexp.duration.Lossofinformation(dottedlines)butfastexperiments.7,.,56,ResolutioninSECMEffectofStepWidth,5m12.5m,2m50m,10mPttip,workingdistance5m,10my-increment,5mMFe(CN)64-in100mMKCl,RE:Ag/AgCl(3MKCl),Etip=+500mV,8,.,57,I=i/i,0,2,4,6,8,10,3210,4,L=d/r,1,2,10mPttip,12.5mx-increment,10my-increment,5mMFe(CN)64-in100mMKCl,RE:Ag/AgCl(3MKCl),Etip=+500mV,WD25m(5r),WD5m(r),Workingdistancedeterminescontrast!,9,.,58,ResolutioninSECMECdeterminestheresolution!Thechoiceoftheelectrodesizeandtheparameterstepwidth(distancebetweendatapoints)iscrucial.dr,Thepositioningsystemhasasufficientrepeatability(bidirectional15msteppermotorsand10nmpiezosystem).,10,.,59,ComparisonFeedbackandGCMode,5mMRu(NH3)63-in100mMKCl,RE:Ag/AgCl(3MKCl),forGC:WE1:2ndbandEsample=-400mV,WE2:25mPttip,Ru2+,Ru3+,0mV,Ru3+,Ru2+,Ru3+,Ru2+,-400mV,11,.,60,ComparisonFeedbackandGCMode,5mMRu(NH3)63-in100mMKCl,RE:Ag/AgCl(3MKCl),forGC:WE1:2ndbandEsample=-400mV,WE2:25mPttip,+sensitivitylateralresolution(diffusionprofiles)timedependency,+lateralresolutionhighbackgroundcurrentredoxmediatorrequired,12,.,61,workingdistancedependsontipsize,tipcrash,Constant-Heightvs.Constant-DistanceModeSECMWhenusingaverysmallprobe(sub-m),orscanningaroughsample,thedistancedependencyofthecurrentsignalcancausedifficulties.lossofnearfieldinteraction,13,.,62,Constant-HeightModeSECM,itip,z-position,ii,Electrochemicalactivityandtopographyinfluencethetipsignal(datainterpretationdifficult).,14,.,63,Constant-DistanceModeSECM,itip,z-position,i,Tipfollowstopographyandthetipsignalrepresentstheelectrochemicalactivity.,15,.,64,magnitude/mV,RequiresspecialvibratorySECMtips,Constant-DistanceSECMDetectionofshearforceinteractionsforcurrentindependentdistancecontrolPiezoelement,Agitator,Detector,86420,10,200,250,350,400,300frequency/kHz,solutionsfregime,16,.,65,MAG/mV,Constant-DistanceSECMApproachCurve,0,1,2,3,64,161412108,interactionrange,contact,bulksignalsetpointshearforce,z-position/m17,.,66,Constant-Dista