电极过程动力学陈胜利

化学学院物理化学专业研究生课程,“电极过程动力学”,授课教师：陈胜利Tel:68754693Email:slchenOffice:化学楼135,授课教材,查全性等著：电极过程动力学导论（第三版，科学出版社，2002年）,推荐参考书,WrittenbyAllenJ.BardandLarryF.Faulkner,ElectrochemicalMethods:FundamentalsandApplications（SecondEdition,Wiley,2001）,邵元华等译,电化学方法：原理及应用（第二版，化学工业出版社,2005年）,Chapter1,INTRODUTIONANDOVERVIEWOFELECTRODEPROCESSES,Electrochemistry?,Thelaws(principles)andthetechnologiesconcerningtheconversionbetweenchemicalenergyandelectricalenergyInterrelationbetweenchemicalphenomena(chemicalreactions,chemicalchanges,etc.)andelectricphenomena(charge,current,potential,electricfield,etc.),Withahistoryofmorethantwocenturies,electrochemistryhasbeenatypicalexampleofatrulyinterdisciplinary(各学科间的)areaofscienceandtechnology.Itsrootshavebeeninchemistry,physics,materialsandbiologicalscienceanditsapplicationsspreadingfromelectrochemicalanalysisandsynthesistoenvironmentalprotectionandenergyconversionandstorage.Everydaylifeitemssuchasbatteries,theglucose（葡萄糖）sensoranddomesticormedicalgassensorsarenowacommodity,whiletheprospectofmassproductionofgreenelectricvehicles(Electricvehicles)isnomoreachallengebutaviableoption.Onanindustrialscale,apartfromthenowmaturechlor-alkaliandmetalfinishingandextractionindustries,thereissignificantactivityintheareasofenergyconversionandstoragebymeansoffuelcellsandsolarcellsaswellasintheuseofelectrochemicalmethodsforeffluenttreatment.“Electrochemistryprovidesmanyopportunitiesforsustainabledevelopment.”,ElectrochemicalCellsandReactions,Pt,Pt,Pt,Pt,H2SO4Solution,H2,O2,H2,O2,H+,H+,H2O,H+,H2O,H+,e,e,e,e,Cathode:1/2O2+2H+2e-=H2OAnode:H2=2H+2e-Overallcellreaction:H2+1/2O2=H2O,Positiveelectrode:H2O=1/2O2+2H+2e-Negativeelectrode:2H+2e-=H2Overallcellreaction:H2O=H2+1/2O2,GalvanicCell（原电池）,VoltaicCell,H+,H+,Thefeaturesofelectrochemicalreactions,Theoverallredoxreactionismadeupoftwohalf-reactionstakingplaceindependentlyattwolocationswhereelectronicconductors(Electrodes)andionicconductors(electrolytes)aremadeincontact;Charge(electronorions)transferbetweentheelectrodesandchemicalspeciesalwaysoccursandacurrentflowsinexternalcircuitbetweentwoelectrodes;Theextentandthedirectionofthereactioncanbealteredbythepotentialsappliedtotheelectrodes;,Electrodereactionatelectrode/solutioninterfaces,Chargetransferplane,Feimilevel,LUMO,HOMO,Chargetransferplane,Feimilevel,Potentialshiftsnegatively,e,ForExample:,Possibleprocessesinvolvedinanelectrodereaction,Oad,O,Rad,R,O*,R*,ne,Ob,Rb,Masstransfer,Masstransfer,PrecedingChemicalreactions,FollowingChemicalreactions,Electrode,Chargetransfer,Adsorption,Desorption,Whatwillwedealwithinthiscourse?,ThekineticsoftheelectrodereactionsofvarioustypeandthefactorsthataffectthesekineticsCurrentPotentialdependence,Thephilosophyinelectrochemicalstudies,Schematicthree-electrodecellusedinelectrochemicalstudies,StandardHydrogenElectrode(SHE),Pt,CH+=1mol.l-1,H2,H2,Saturatedcalomelelectrode(SCE),Metalwire,KClsolution,Hg2Cl2,Hg,Ptwire,Strategiestostudytheelectrodeprocesses,Potential-controlledtechniques,Current-controlledtechniques,Potentiostatic（恒电势）methods,Potentiodynamicmethods,Abriefdescriptionoftheelectricdoublelayeranditseffectsontheelectrodereactionkinetics,Thedoublelayerisaresultofre-arrangementandorientationofthechargesandthedipolesattheelectrode/electrolyteinterface.Theelectrodeandtheelectrolytebearthesameamountofchargeswithoppositenature:qM=-qS;Thedoublelayerconsistsoftworegions:Compactlayer(alsocalled“innerHelmholtzlayer”or“sternlayer”)anddiffuselayer(alsocalled“outerHelmholtzlayer”);Theeffectivepotentialtodrivetheinterfacialchargetransfermaybesignificantlydifferentfromthatappliedthetheelectrode/solutioninterface:Eeff=Eapp(1),Thecapacitor（电容器）-likenatureoftheelectricdoublelayer,Regardlessofthenatureofanelectrodeprocess,thedoublelayeritselfwouldresponsetotheelectrochemicalperturbationsasaseriesofcapacitorsThecapacitancevaluesofthedoublelayerarepotential-dependentMostoftheelectrochemicalmeasurementsaremoreorlessaffectedbythechargingprocessofthedoublelayer,Thedoublelayerchargingeffectsinelectrochemicalmeasurements,E,=RsCdi=0