《Density Functional Theory Comparison of Methanol Decomposition and Reverse Reactions on Metal Surfaces.docx》由会员分享，可在线阅读，更多相关《Density Functional Theory Comparison of Methanol Decomposition and Reverse Reactions on Metal Surfaces.docx（13页珍藏版）》请在金锄头文库上搜索。
1、iCatalispubs.acs.org/acscatalysisDensityFunctionalTheoryComparisonofMethanolDecompositionandReverseReactionsonMetalSurfacesRodrigoGarcia-Muelas；QiangLi,andNuriaLopez*InstituteofChemicalResearchofCatalonia(ICIQ).Avgda.PaisosCatalans16,43007Tarragona,Catalonia,SpainSupportingInformationsootEJXH一s=qnda
2、laqsAoaoqlao一s3qcosuo=doso.Qp3s3.mqs3JOsoc3sq2d0.sdlaDOSuHe&6L6036一OTP乎云qEwbscoADOUONSEaNVUJONUJ一osA-ND5HNV.2AP0P8一umoqABSTRACI:Methanoldecompositiononmetalshasbeensubjectofseveraltheory叫祖血散岖!allyccyicentratingoaparticularsetofreactionsinthemainreactionpath.Inthiswork,wepresentaneefisiy”elementaryst
3、epsforfourclose-packedsurfacesincludingCu,Ru.P(,andP(|ihaisalternativeroutesthroughwhichthedecompositioncantakeplacebycontributions.Decompositionfollowsdifferentpathsonthesemetals;whilewoiproductfortheothermetals.Inaddition,coverageeffectsmightchangethefi。stepZINTRODUCTIONT-StBdythntpolishersallpote
4、ntt也做(H*differentbaviorsEmethods；includingwouhI_prodvecCH2O,CO敌inPtandRufromalcoholHactivation.Alternativelythereactionnetworkcanbeinspectedforthb.forniation.o.methajiwrhydrogen.Undertheseconditions,CugeneratesCH2OandonlyatveryhighHcov如siappear.歪Pd,methanolformationandCHOHdissociationcompete,thuslea
5、dingtoaninefficientprocess.AsimilarpathtakesplaceforPt.ForRuthelateralpathsleadingtoC-0breakingcanoccuratseveralpointsin(hereactionnetwork,neverreachingCH3OH.Acompilationoftheresultswithcomparablecomputationalsetupspresentsadetaileddatabasethatcanbeaddedtothethermodynamicsandkineticsforotherreaction
6、s,suchasmelhanation.withwhichtheyshareacommonlistofreactions,oremployedwhenanalyzinglargeralcoholssuchasthosederivedfrombiomass.KEYWORDS:methanol,densityfunctionaltheory,Br0nstedandEvans-Polanyi(BEP)relationships.Pt,Pd,Ru,CuthegroupofCampbellshowedthatthemethoxyradicaladsorbedonPt(111)isratherunstab
7、le,aswaspredictedbyDFTstudies.10ForthesamesystemNeurockandco-workers11foundthat,underultra-highvacuumconditions,methanolMethanolisthesmallestofallalcoholsand,asitisaliquidandiseasytostore,ithasbeenpresentedasapotentialenergyvectorthatcanbeemployedinnewenergyapproaches.Indeed,themethanoleconomyconcep
8、twascoinedinthe199()stoaccountforthispossibility.1Theuseofmethanolinmobileapplicationsseemedtohethemostpromising,asitcanbedirectlyusedasfuelincombustionengines,directlyconvertedtoenergyinelectrochemicalcells,orconvertedintoanotherenergyvectorsuchashydrogen.2Severalofthoseapproachesarebasedonitselect
9、rochemicaltransformationandthecorrespondingenergyrelease,buttheproblemofdirectmethanolfuelcellscomesfromthestrongadsorptionofoneofthesubproducts,namelyCO.AlthoughmethanoliscurrentlyproducedbyhydrogenationofamixtureofCOandCO：inaCu/ZnOcatalyst.3,4itisalsopossibletoproduceitfromagriculturalproductsandm
10、unicipalwaste,makingitarecycledproduct.Methanolisalsoemployedasasurrogateforlargerbiomass-derivedalcohols,5evenif(hisapproachmightbeoverlysimple.Methanoldecompositionandsynthesisonmetalsurfaceshasbeenextensivelyinvestigatedbyseveralauthorsduring(hepastdecade.GreeleyandMavrikakisalsoinvestigatedmetha
11、noldecompositiononCu(Hl).6wherethepreferredpathwouldstartbythedehydrogenationof(hehydroxylgroup.In(hedecompositionrouteonPt(l11).7,8(hesameauthorsstudiedareactionnetworkeitherstartingwith(hedissociationofthealcoholhydrogenorstartingfrom(hemethylenicHatoms.ACSPublicationsv&2014AmericanChemicalSociety
12、Accordingto(hem,carbondehydrogenationwouldbeapreferredstep,incontrastwiththepreferentialO-Hbondbreakingfoundinexperimentalstudies.9Arecentstudybywoulddesorbratherthanreact,astheactivationbarrierslorthefirstdehydrogenationarehigherthanthedesorptionenergy.Inthestudy,twointennediateswerediscardedduetoc
13、omplexity,CHOHandCOH;aswewillshow,bothmightbelongtotheminimumenergypath.TorationalizelheresultsforPt,severalattemptshavebeenmade.Accordingto(hed-bandmodel,(heactivityofametalisafunctionoflhed-bandcenter.1214ThisanalysiswasemployedbyParkandcoworkers15tostudythemethanolelectrooxidationactivityofPt.Inp
14、arallel.Ferrinandco-workersdemonstratedthatthecatalystperformanceformethanolclcctrooxidationcanbedescribedasafunctionofthefreeenergyofadsorptionofCOandOHradicals.16However,theadsorptionenergiesandd-bandpositionsarccorrelated,astheenergiesarcafunctionofthed-bandpositions.14Yudanovandco-workersfocused
15、onC-ObondbreakingonPdnanoparticles,identifyingitasaslowsideprocessinthedecompositionreaction.17OnPdandothermetals,theReceived:November3.2014Revised:December23.2014Published:December31,2014decompositionordehydrogenationstepshavebeencompiledforalargerangeofmoleculesandfragmentscontainingthesameheteroa
16、tom.18,19AsibrRu(0001),experimentshaveshownthecoexistenceoftwopaths,oneleadingtoCOandtheotheroneleading10CandOseparatefragments,wherethesecondpathwasidentifiedasresponsibleforsurfacepoisoning.2ThereasonisthatH-assis(cdreactionshavebeenfoundtolowerthebarrierstodifficultdecompositionssuchasthatofCO.21individualmetals(shownbycolors)canillustratethedifferencesother(hanfromaveryqualitativeanalysis.Finally,wehaveconsideredthedependenceofth
