物理化学研究方法

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1、PotentialStep（Chronocoulometry)SpectroelectrochemistryOCPCurrentStepVoltammetricAnalysisEISPolarographyRDERRDECyclicvoltammetryCyclicpotentialsweepResultingcyclicvoltammogram(initialpotentialandswitchingpotential)Nernstian(reversible)systemsPeakcurrentislinearwithsquarerootofsc

2、anrateNoeffectsofscanrateonpeakpotentialReductivepeakcurrentisequaltooxidativepeakcurrentValueofpeakpotentialdifferenceis58mV/nPeakcurrentandscanrateAt25℃,ipisTotallyirreversiblesystemsThree-electrodecellandnotationforthedifferentelectrodesScanrateInLSV,thepotentialisscannedfro

3、malowerlimittoanupperlimitUnitofscanrate(υ):V/sormV/sEffectsofscanrateonchargingcurrent:DifferentialPulseVoltammetry/PolarographyDifferentialPulseVoltammetry/PolarographySMDEStablesurfaceNeedleCapillaryTapperHgdropDMEDroplifeNewDropElectrodetypesinVoltammetricAnalysisStaticMerc

4、uryDropElectrodeDroppingMercuryElectrode技术参数：主要应用领域：>重金属分析>有机物分析>测定阴离子>伏安极谱痕量分析订货信息：>2.663.0024:VAStand663多功能汞电极工作台。>旋转圆盘电极的配件：包括转动轴、各种电极头（超痕量石墨头、GC、Ag、Pt和Au）、抛光材料多功能汞工作台VA663SampledCurrentPolarographySampledCurrentPolarographySampledCurrentPolarographyPotentialstepSignalResult

5、ingi-tcurveConcentrationprofilesforvarioustimesintotheexperimentPotentialwaveformforchronoamperometryandchronocoulometryChangeParametersdialogboxforchronoamperometry/chronocoulometryCurrent-timeresponseforadouble-potentialstepchronoamperometryexperimentPotentialstepunderdiffusi

6、oncontrolCottrellequation:Instrumentalandexperimentallimitations:(1)Potentiostaticlimitations,(2)limitationsintherecordingdevice,(3)limitationsimposedbyRuandCd,(4)limitationsduetoconvection:theavailable“timewindow”forCottrellmeasurementsliesapproximatelybetween20μsecand200sec.L

7、imitationsimposedbyRsandCdNotethatforapotentialstepinput,anexponentiallydecayingcurrentisobtained,withatimeconstant,τ=RsCd,hence,thecurrentforchargingthedouble-layercapacitancedropsto37%ofitsinitialvalueatt=τChronocoulometryAtt=0,thepotentialisshiftedtoE2,whichissufficientlyneg

8、ativetoenforceadiffusion-limitedcurrent.Thefollowingeq