多晶Pt、Pd电极真实表面积的确定与Pd40Pt电极氧还原活性的初步分析

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1、ABSTRACTProtonexchangemembrancefuelcellO'EMFC)aretypicalfuelceilsworkingatrelativelylowtemperatures(

2、dzeroemission．StateoftheartanodeandcathodeelectrocatalystsusedinthesefuelcellsaregenerallyPt—basednoblemetalcatalysts．Theimprovementofactivityandlifetimeoftheelectrocatalyst(especiallyatthecathodeforoxygenreductionreaction，ORR)andreductionoftheloadingofnobelmetalssuch

3、asPt，arethekeyfactorsforlargescalecommercializationofsuchfuelcells．InordertoevaluatetheelectrocatalyticactivityofPt(orPd)-basedeleetroeatalystsandtoimprovethecatalyticperformance，knowledgeoftherealsurfaceareaofsuchelectrodesisextremelyimportant，becauseitisrequiredtoca

4、lculatethespecificactivityofagivenelectrochemicalprocess．Inordertohelpinsolvingtheabovementionedproblems，twosmallprojectshavebeencarr⋯iedoutinthisthesis．Firstly，fourdifferentmethods，i．e．，doublelayercapacitancemeasurementsandadsorptionofprobemoleculesormetalatomshavebe

5、enappliedtoevaluatetherealsurfaceareaofpolycrystallinePd／PtandroughPtfilmelectrodes．Andthevaluesdeterminedfromdifferentapproachesalecarefullycompared，theapplicabilityandlimitationsassociated、^，itlldifferentapproachesarediscussed．Then，electrocatalystscomposedofPtoverla

6、yerswithvariousthicknessandPt；PtatomicratiohavebeenpreparedandtheirstructuralpropertiesandORRactivityhavebeenstudied．Theresultsarebrieflysummarizedbelow．——、DeterminationoftherealsurfaceareaofpolycrystallinePd／PtandroughPtfihnelectrodes．1)Fourdifferentmethodshavebeenex

7、ploitedtOdeterminetherealsurfaceareaofapc—Pdelectrode．ThesurfaceareadeterminedfromoxygenadsorptionorⅡIABSTRACTdoublelayercapacitanceagreeswell埘theachother，whilethemethodWithCuupdgivesasmallervalue(ca．5％)．OurresultsrevealthatthesaturationcoverageofCOatpc—Pd、ⅣithCOdoese

8、d0．35Visca．0．66ML．TheseresultsrevealthatallthesefourmethodsCanbeusedforthedeterminationoftherealsurfaceareaofsmoothpc—Pdelec