2020/5/201现代电化学分析测试研究方法ModernElectrochemicalMethods陈昌国教授cgchen@cqu.edu.cn2015-3[现代电化学工程:]2020/5/202主要参考书:2ndEd(2001)ByAJBard&LRFaulkner图书馆有第1版中译本2)Electrochemicalmethods:Fundamentalsandapplications1)电化学测量.2020/5/203ModernElectrochemistry(2002,2ndEd)2020/5/204ModernElectrochemistry(2002,2ndEd)J.O’MBockrisandS.U.M.Khan,“SurfaceElectrochemistry–amolecularlevelapproach”,PlenumPress,NY(1993,2000)2020/5/2051.概述—关于电化学测量:•电极过程动力学【电化学原理、理论电化学】•电化学测量方法【含电化学分析】•应用电化学【电化学工程—电池、腐蚀、电镀】【化学电源、腐蚀与防护、表面工程、电解加工…】现代电化学:2020/5/206现代电化学测量方法—主要内容:1.概述—关于电化学测量2.控制电位法3.控制电流法4.交流阻抗法5.光谱电化学方法6.量子电化学方法2020/5/207现代电化学测量方法—内容:2020/5/208电化学测试技术:主要教学内容(应用化学专业)•稳态极化曲线与动力学方程式•稳态极化曲线的测定•暂态法总论•控制电流暂态法•控制电位暂态法•交流阻抗法•电极与电解池•电化学测试中常见的电子线路•谱学电化学研究方法与电化学研究方法的发展趋势•电化学测试技术的应用示例2020/5/2091.概述—关于电化学测量1.1电化学测量——原理1.2ThreeElectrodesSystem—SingleElectrode1.3恒电位技术—PotentiostaticTechnique1.4恒电流技术—GalvanostatTechnique1.5恒电位仪与电化学工作站—Galvanostat&ElectrochemicalWorkStation2020/5/20101.1电化学测量——原理•控制电位法E:测量I(计算Z(E)=U/I)•控制电流法I:测量E(计算Z(I)=E/I)•交流阻抗法Z:测量Z(EorIorf)(=E/I)Z(EorI)IIE2020/5/2011•Anode:electrodecompartmentwhereoxidationoccurs•Cathode:electrodecompartmentwherereductionoccurs•Half-cell:compartmentwherehalf-reactionoccurs+—CellSystem——Terminology2020/5/2012•CE:CounterElectrode•WE:WorkingElectrode•RE:ReferenceElectrode1.2ThreeElectrodesSystem:SingleElectrode“两回路”:控制主回路测量显示回路2020/5/2013三电极体系的基本组成:(1)研究电极(WorkingElectrode):(2)辅助电极(CounterElectrode):大面积(3)参比电极(ReferenceElectrode):不极化(4)盐桥(SaltBridge):(5)隔膜(Membrane):分隔辅助电极与研究电极之间的溶液(6)鲁金毛细管(LugginCapillary):2020/5/2014重现性好抛光技术:机械抛光机械压制化学抛光电化学抛光封装技术:WorkingElectrode:大面积:稳定:无污染:CounterElectrode:2020/5/2015ReferenceElectrode:不极化,可逆性好稳定,重现性好温度系数小制备简单维护方面保存容易常用参比电极的电位:2020/5/2016现代电化学——内容1.3恒电位技术—Potentiostatic经典恒电位电路—大功率蓄电池和低阻值滑线电阻由运算放大器组成的恒电位电路2020/5/2017实际恒电位电路:2020/5/20181.4恒电流技术—Galvnostatic由运算放大器组成的恒电流电路经典恒电流电路—高电压蓄电池组和高阻值滑线电阻2020/5/2019实际恒电流电路:2020/5/20201.5恒电位仪与电化学工作站:2020/5/20211.5恒电位仪与电化学工作站:2020/5/20221.5恒电位仪与电化学工作站:2020/5/20231.5恒电位仪与电化学工作站:2020/5/20241.5恒电位仪与电化学工作站:2020/5/20251.5恒电位仪与电化学工作站:LK98BIICHI660A2020/5/2026电化学工作站:-概述国外主要的电化学工作站仪器型号厂家(公司)国别1200系列SolartronAnalytical英国2000、7000系列AMELsrl意大利Autolab系列ECochemie荷兰BAS系列BioAnalyticalSystems美国CHI系列CHInstrument美国EG&G270系列PrincetonAppliedResearch美国IM6/6e系列ZAHNERElektrik德国OMNI90系列CypressSystems美国PG系列HEKAInstrument德国PINEAF系列PineInstrument美国Powerlab系列ADInstruments澳大利亚PS-205系列ELCHEMA美国Voltalab系列RadiometerAnalytical法国……2020/5/2027ECWindow—inH2OSolution2020/5/20282.Controlled-PotentialTechnique2.1PotentialStep—ChronoAmperometry2.2LSV—LinearSweepVoltammetry2.3CV—CyclicVoltammetry2.4ACV—AlternatingCurrentVoltammetry/5x10-7M2.5SWV—Square-WaveVoltammetry/10-8M2.6NPV—Normal-PulseVoltammetry2.7DPV—Differential-PulseVoltammetry/10-9M2020/5/20292.1PotentialStep:(1)ChronoAmperometry2020/5/2030DoublePotentialStep(dincreaefromatoe)0.1MKe4Fe(CN)6+0.2MK2SO4onPt2.1PotentialStep:(1)ChronoAmperometry2020/5/2031Including:SolidPhaseformation(Nucleation)Pb→PbO22.1PotentialStep:(1)ChronoAmperometry2020/5/20322.1PotentialStep:(2)PolarizedCurve—PassivationCurve:Niin0.2MH2SO42020/5/20332.1PotentialStep:(2)PolarizedCurve2020/5/2034—TafelCurve2.1PotentialStep:(2)PolarizedCurve2020/5/20352.2LSV—LinearSweepVoltammetryO+ne-RExcitationWaveform2020/5/2036LSV—Stripping2020/5/20372.3CV—CyclicVoltammetryO+ne-RExcitationWaveform2020/5/2038CV—Peak:ip&Ep53/21/21/2p2.6910inACDv1/2p~ivp~iCCotroll方程——峰电流Nernst方程——峰电位可逆反应——峰参数2020/5/2039CV—ReactionReversibility2020/5/2040CV—电化学实验控制参数:初始电位终止电位扫描速度扫描方向扫描周期数或单方向扫描记录方式:伏安曲线、电流时间曲线记录精度2020/5/2041正向峰电流iPC正向峰电位fPC正向半峰电位fp/2C正向峰面积SC逆向峰电流iPA逆向峰电位fPA逆向半峰电位fp/2A逆向峰面积SA峰电位差DfCV—电化学实验测定参数:2020/5/2042(1)ipc/v1/2与v的关系(2)dEP/v与v的关系(峰电位移动dEp)(3)ipc/ipa与v的关系(4)峰电位差与v的关系CV—研究电化学反应的理论依据:2020/5/2043反应物与生成物均可溶:O+neR(1)峰电流规律:–可逆反应:iP与v1/2成正比–不可逆反应:ipc与v1/2成正比;ipa=0–准可逆反应:ipc与v1/2随v增加而增大,但不成正比(2)峰电位规律:–可逆反应:EP与v无关–不可逆反应:dEp随v增加而增大:dEp/2/dv=30mV/αn–准可逆反应:dEp随v增加而增大:dEp/2/dv≤30mV/αnCV—研究电化学反应的理论结果:2020/5/2044CV—Poly-Ptin0.5MH2SO42020/5/2045CV—C60inAcetonitrile/Toluene2020/5/2046CV—Thin-LayerElectrolyticCell&ScanRateCVsof0.1MKe4Fe(CN)6+0.2MK2SO4onPt2020/5/2047CV—MicroElectrode&ScanRate2020/5/2048CV—PB-ModifiedElectrodeThinFilmCVofPrussianBluemodifiedelectrodein1MKCl(3mV/s)BerlinGreenPrussianBluePrussianWhiteBGPBPW2020/5/2049CV—Agin1MNaOH2020/5/2050CV—CrystalPlane:Ptin0.1MHClO4•0.1MHClO4(brokencurves)•+1mMH2SO4(solidcurves)Pt(100)Pt(poly)Pt(110)2020/5/2051CV—CrystalPlane:Ptin0.5MH2SO4Pt(111)Pt(110)Pt(100)2020/5/2052CV—CrystalPlane:Ptin0.5MH2SO4Ptn(111)x(111)50mV/s(1991)2020/5/2053•Cl-?CV—UnstableProduct:Pt/1MCH3OH+1MH2SO42020/5/2054CV—UnstableProduct:Pt/0.1MCH3OH+1MHClO4MSDetectPorousPtRoughnessc.5020mV/s(1990)2020/5/2055CV—小孔腐蚀Fe的小孔腐蚀模型inNaCl(pH=10)自催化使顺扫曲线与逆扫曲线形成滞后环2020/5/2056CV—UnstableProduct???Pt/0.27MNaBH4in1.5MNaOH(5mV/s)直接氧化:NaBH4+8OH−→NaBO2+6H2O+8e−水解:NaBH4+2H2O→4H2↑+NaBO22020/5/2057CV—∫dt1/2&d1/2/dt1/22020/5/2058CV—∫dt1/2&d1/2/dt1/22020/5/2059CV—∫dt1/2&d1/2/dt1/22020/5/2060CV—∫dt1/2&d1/2/dt1/22020/5/2061CV—∫dt1/2&d1/2/dt1/2Q(t)=∫I(