从银电极上氢析出的温度效应得到的反应动力学启示-论文.pdf

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1、CHINESEJoURNALoFCHEMICALPHYSICSVoLUME27．NUMBER1FEBRUARY27．2014ARTICLEKineticImplicationfr0mTemperatureEfectonHydrogenEvolutionReactionatAgElectrodeJingKang，Chu—hongLin，YaoYao，Yan—xiaChenH@eiNationalLaboratoryforPhysicalSciencesatMicroscale，DepartmentofChemicalP

2、hysics，Uni-versityofScienceandTechnologyofChina，Hefei230025，China(Dated：ReceivedonMay28．2013；AcceptedonJune8，2013)HydrogenevolutionreactionfHER1atpolycrystallinesilverelectrodein0．1mol／LHC104solutionisinvestigatedbycyclicvoltammetryinthetemperaturerangeof278-33

3、3K．Wefoundmatatelectrodepotential~

4、ntialforHERtothepotentialofzerocharge(PZC≈一0．4V)，bothEa，appandAforHERincrease(e．g．，Ea，appincreasesfrom24kJ／molto32kJ／mo1)．TheincreaseinEaandAwithnegativeshiftinfrom-0．25VtoPZCisexplainedbytheincreasesofbothinternalenergychangeandentropychangefromreactantstothet

5、ransitionstates．whichiscorrelatedwiththechangeinthehydrogenbondnetworkduringHER．Thepositiveentropyefectsovercompensatetheadverseefectfromtheincreaseintheactivationenergy．whichleadstoanetincreaseinHERcurrentwiththeactivationenergynegativeshiftfromtheonsetpotenti

6、alofHERtoPZC．Itispointedoutthatentropychangemaycontributegreatlytothekineticsforelectrodereactionwhichinvolvesthetransferofelectronandproton，suchasHER．Keywords：Hydrogenevolutionreaction，Agelectrode，Temperatureefect，Activationenergy，Pre—exponentialfactor，Interna

7、lenergy，EntropychangeI．INTR0DUCT10NOrthroughtheTafelreaction，i．e．，thecombinationoftwoadsorbedHatomsandthesubsequentdesorptionHydrogenevolutionreaction(HER)isatypicalmodelOfH2，reactionforunderstandingtheprincipleofelectrocatal—Had+Had__÷H2ysisduetothesimplicityo

8、fitsreactionmechanism[1]．TheoverallreactionforHERinacidicelectrolyteis：TheefrectofcatalyststructureontheHERactiv—ityhasbeenextensivelystudiedinthepastyears．a2H+(aq)+2e．．+H2(