ElectrochemicalandElectrocatalyticReactionsof

ElectrochemicalandElectrocatalyticReactionsofCarbonDioxideEditor-in-Chief:B.RSullivanDepartmentofChemistryUniversityofWyomingLaramie,WY,USAAssociateEditors:K.KristGasResearchInstituteChicago,IL,USAH.E.GuardOfficeofNavalResearchDepartmentoftheNavyArlington,VA,USA1993ELSEVIERAmsterdam•London•NewYork•TokyoELSEVIERSCIENCEPUBLISHERSB.V.SaraBurgerhartstraat25P.O.Box211,1000AEAmsterdam,TheNetherlandsLibraryofCongressCataloging-in-PublicationDataElectrochemicalandelectrocatalyticreactionsofcarbondioxide/editedbyB.P.Sullivan,K.Krist,H.E.Guard.P.cm.Includesbibliographicalreferencesandindex.ISBN0-444-88316-91.Carbondioxide.2.Electrochemistry.3.Catalysis.I.SullivanB.P.(B.Patrick)II.Krist,K.III.Guard,H.E.QD181.C1E441992546'.6812—dc2092-34495CIPISBN:0-444-88316-9©1993ElsevierSciencePublishersB.V.Allrightsreserved.Nopartofthispublicationmaybereproduced,storedinaretrievalsystemortransmittedinanyformorbyanymeans,electronic,mechanical,photocopying,recordingorotherwise,withoutthepriorwrittenpermissionofthepublishers,ElsevierSciencePublishersB.V.,Copyright&PermissionsDepartment,P.O.Box521,1000AMAmsterdam,TheNetherlands.SpecialregulationsforreadersintheU.S.A.ThispublicationhasbeenregisteredwiththeCopyrightClearanceCenterInc.(CCC),Salem,Massachusetts.InformationcanbeobtainedfromtheCCCaboutconditionsunderwhichphotocopiesofpartsofthispublicationmaybemadeintheU.S.A.Allothercopyrightquestions,includingphotocopyingoutsideoftheU.S.A.,shouldbereferredtothecopyrightowner,ElsevierSciencePublishersB.V.,unlessotherwisespecified.Noresponsibilityisassumedbythepublisherforanyinjuryand/ordamagetopersonsorpropertyasamatterofproductsliability,negligenceorotherwise,orfromanyuseoroperationofanymethods,products,instructionsorideascontainedinthematerialherein.Thisbookisprintedonacid-freepaper.PrintedinTheNetherlands.PREFACETherecyclingofatmosphericmoleculesforuseasfuelsandchemicalsisagoalwhichcanbeachievedonlywithadeeperunderstandingofcatalyticprocesses,particularlyelectrocatalysiswherebyredoxtransformationscanbeinterfacedwithsolarornuclearenergyinput.Carbondioxideisaprototypicalsmallmoleculeinmanyregardssinceitischemicallyinert.Inaddition,becauseofthelikelyroleofcarbondioxideingobaltemperaturecycles,itmaybethatfutureregulationofoutputfromindustrialprocesseswillbedesirable.Itisthepurposeofthisvolumetopresentaunifieddiscussionofthecarbondioxidechemistrythatisnecessaryfortheunderstandinganddesignofelectrochemically-drivenprocessesforthereductionofcarbondioxide.Theorganizationofthisvolumeisasfollows.First,inchapter1,apresentationofthermodynamicsandkineticsofcarbondioxidereactivitysetsthestageforanin-depthdiscussionofthebindingofcarbondioxidetotransitionmetalcentersinchapter2.Chapter3presentsmechanisticinterpretationsofperhapsthemostimportantcatalyticreactionofC02,thewater-gasshift.Inchapter4methodsfortheconcentrationofC02,whichcouldproveusefulforprovidingfeedstocksforcatalyticsystems,arepresented.Chapter5summarizesthestate-of-the-artconcerningelectrochemicalmechanismsofC02reductionatmetalcenters,focusingprincipallyontheprocessesthattakeplaceinhomogeneoussolution.Chapters6and7aredevotedtoaspectsofthereductionofC02atmetalelectrodes,bothinpreparativeandmechanisticdetails.Lastly,chapter8coversthemoreunusualphotochemicalandphotoelectrochemicalmethodsofactivatingandreducingcarbondioxide.Itishopedthatthisvolumewillprovideanimpetusforfurtherdevelopmentofelectrocatalyticcarbondioxidechemistry.B.PatrickSullivanLaramie,WyomingJune1992LISTOFCONTRIBUTORSW.BellRonaldL.CookCarolCreutzDanielL.DuBoisPeterC.FordKarlW.Frese,Jr.F.RichardKeeneNathanS.LewisA.MiedenerAnthonyF.SammellsGaryA.ShreveJ.C.SmartB.PatrickSullivanSolarEnergyResearchInstituteGolden,CO80401EltronResearch,Inc.Aurora,IL60504ChemistryDepartmentBrookhavenNationalLaboratory,UptonNY,11973SolarEnergyResearchInstituteGolden,CO80401DepartmentofChemistryUniversityofCaliforniaSantaBarabara,CA93111InterfacialSciences,Inc.SantaClara,CA95051JamesCookUniversityofNorthQueenslandDepartmentofChemistryandBiochemistryTownsville,Queensland4811,AustraliaDepartmentofChemistryandChemicalEngineering,CaliforniaInstituteofTechnology,Pasadena,CASolarEnergyResearchInstituteGolden,CO80401EltronResearch,Inc.Aurora,IL60504DepartmentofChemistryandChemicalEngineering,CaliforniaInstituteofTechnology,Pasadena,CASolarEnergyResearchInstituteGolden,CO80401DepartmentofChemistry,UniversityofWyoming,Laramie,WY82071-3838Chapter11THERMODYNAMIC,KINETIC,ANDPRODUCTCONSIDERATIONSINCARBONDIOXIDEREACTIVITYF.RichardKeeneDepartmentofChemistryandBiochemistry,JamesCookUniversityofNorthQueensland,Townsville,Australia4811Therehasbeenarecentupsurgeininterestinthereactivityofcarbondioxidefortwoprimaryreasons.Firstly,carbondioxideistheultimateby-productofallprocessesinvolvingoxidationofcarboncompoundsanditsincreasingpresenceintheatmospheresincethebeginningoftheIndustrialRevolutionhasgivenrisetowidespreadconcernaboutpossibleconsequences(theso-calledGreenhouseEffect).Secondly,inviewofthevastnessofitssupply,carbondioxiderepresentsapossiblepotentialsourceforQfeeds