用于高效且可擴展二氧化碳轉化的低功耗可調諧微等離子體裝置 Low-Power Tunable Micro-Plasma Devices for Efficient and Scalable CO2 Conversion

EPFLThesisn°11053

LOW-POWERTUNABLEMICRO-PLASMADEVICESFOREFFICIENTANDSCALABLECO2CONVERSION

Presentedon27thJune2025

SchoolofBasicSciences

LaboratoryofSustainableandCatalyticProcessing

DoctoralprograminChemistryandChemicalEngineering

fortheawardofthedegreeofDocteurèsSciences(PhD)

by

BartuKARAKURT

Acceptedonthejury’srecommendation

Prof.M.Drabbels,jurypresident

Prof.J.Luterbacher,Prof.E.D.N.Matioli,thesisdirectors

Prof.E.Rebrov,examiner

DrD.Hegemann,examiner

DrM.B.Ruiz,examiner

Ecole

polytechniquefdrale

deLausanne

2025

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Acknowledgements

Unlikethenorm,Ibeginbyacknowledgingmyself.Thisjourneyhasbeenfarmorethanasimplestoryof“Ihadnodata,butIpushedthroughandgotresults.”Reflectingonthesefouryearsandninemonths,IfeelthatIhaveneverearnedanythingmoreinmylifethanthistitle.Idedicatethisthesistomyownresilienceandtothecourageittooktoreturntothedrawingboardespeciallywhenthingswerenotworkingout.Thisworkstandsasatestamenttothatperseverance.

Havingsaidthat,thisachievementwouldnothavebeenpossiblewithouttheinvaluableguidanceofmyadvisors,Prof.JeremyLuterbacherandProf.ElisonMatioli.Theirtrustinmeduringchallengingtimes,alongwiththeirsupportanddedication,keptmeontrackwhenIfeltlost.Iamdeeplygratefultothemforalwaysaskingthetough-butnecessary-questionsandforteachingmehowtothinkandactlikeascientist.TheirvoiceswillcontinuetoguidemeasIfacecomplexproblemsthroughoutmylife.Besidesmymentors,I’dliketothankmyjurymembersProf.EvgenyRebrov,Dr.DirkHegemann,Dr.MarceloRuizandProf.MarcelDrabbelsfortheirvaluablecommentsonmythesisandmakingmydefenseoneofthemostenjoyablemomentsofmyPhD.Theymademyoralexamfeelmorelikeascientificdiscussionratherthanastressfulexamination.AlsoMs.Odegaardyou’reEDCHangelandwithoutyourhelpIprobablywon’tbeablesurvivethelasttwomonthsofmyPhD.Thankyousomuchforeverything.

IwasluckytoworkindifferenttwolabsduringmyPhDanditallowedmetohavemanyfriends.IwanttostartwithSeongmin.Youhavethisuniquecombinationofbeingbrilliantatwhatyouaredoingandbeingkindandgenerouswithotherpeople.Thanksforbeingmy“thirdco-advisor”,pushingmetobecomebetterandallthefunwehadoutsidethelabincludinggymsessions.IwillneverforgetthepartyyouorganizedwithMinkyungatyourplaceformeformybirthdayandI’mlookingforwardtovisitbothofyouasuncleBartusoon.ChloéandLorenz,youweretheoneswhotookmeoutfrommycomfortzonewhenIfirstarrivedinSwitzerlandandmakemefeelathome.Thanksforappreciatingthenaturewithmeandteachingmyparentshowtorow,althoughtheywerealmostgettingdivorcedattheendofthesession.Louisa,youweremyfirstofficemateinthelabandyouhelpedmealottogetthings

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started.YoutaughtmeapersoncansayanythingtoeveryoneaslongasthewordsarewiselychosenandIwillcarrylessonthisfortherestofmylife.YC,westartedourPhDmoreorlessatthesametimeandwewentthroughquitesimilarchallengesduringourPhDs.You’reonehellofathoughguyandjackofmanytrades.You’realsoalwaysreadytoeitherhelporpunchsomeoneinthefaceandprobablyIwillmissthisattitudeofyoursthemost.I’mgladthatwedidn’tshutdownthebeamlineatPSIwhenwethoughtwewerestuckinsidehutchduringthatfreakingnightshift,otherwiseIprobablywon’tbestartingthereasapostdoc.Tom,shouldIcallyouFT?Youhaveagreatsenseofempathyandbigheartwhichallowsyoutoconnectwithotherpeople’semotions.YoualsohavethisamazingabilitytobecomefriendswitheveryonewhichIalwaysadmired.JusttrynottogetdistractedandI’mprettysurethatI’llbehearingoftenaboutyouinthefuture.SorryIdidn’tbecomeaChristianovernightbutatleastwetried.Marie,you’reakindsoulandIalwaysfeltthatyouactuallycaredaboutmeandtriedtobethereformeespeciallywhenIfeltaloneafterImovedtoSwitzerland.Thanksforallthepingpongsessions,datingplacesuggestionsandall4creditswegot“together”andI’msorryforfinishingmytasksbeforetheactualdeadlinebutnotbeforeyourdeadline.Elisabetta,Ialwayslookeduptohowwellyoumanagetokeepworkinghardonyourstuff,beagoodcitizeninthelabandalwaysbethereforthepeopleyoucareabout.Giveyourselfabitmorecredit,seiunadonnaforteeindipendentewhoIconsiderasareferenceforself-reflection.Thankyousomuchforthebiglaughswehadintheoffice,especiallybecausemakingourcommunicationeffortless.YoucomealongwayfromwashingtheglasswareinESRFtobeabletofixaGCvalveinthelab.Davide,you’reoneofthemostchillguysI’veeverseenandwhenwetalkIalwayssensedyourintelligencebehindyouriconicglasses.ThankssomuchforintegratingmetoteamLCPTandgivemechancetomeetwithwonderfulpeopleyouhaveinyourgroup.Michele,you’rethemostchillguyI’veeverseenandsometimesIactuallyfeelsorrywhenIdoacringestreakonyou,especiallywhenIseethefearinyoureyes.Thankyouforkeepingupwithmeandpreservingthisweirdbutsuperfundynamicbetweenus,youbecomeoneofmyclosestfriendsinashortperiodoftime.Sylvie,fromoutsideyou’relikeanironladybutonsomeoccasionsIgettoseetheglimpsesofyourtendersidewhichmakesmewonderwhichpartofyouwasthereinthefirstplace.Thankyousomuchforlisteningtometalkingabouteatinghealthy,caloriesandstuffandthenimmediatelygoonandeat30freakingpiecesofsushi(IknowyouhadlessIalsoateyours)withme,

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probablythiswasthemostBartuthingI’veeverdonewithsomeonefromthelab.Atabay,thevisionyouhavecomparedtoyouryoungageisveryadmirable,rareandvaluable.Thankyouforthenewperspectivesyou’vegivenmeandI’mlookingforwardtoseewhatthefutureisholdingforyou.Zilin,youweremyfavouritepersonintheoffice(yesitwasn’tYC).Luca,mybiggestregretisthatwecouldn’tgotoaTurinvs.Juventusgameandshout“…ostetrica”towardsJuve.Butit’sokay,thankyousomuchforimprovingmyItalianbeyondimagination.Iwillmisslookingateachotherandstartsmilingwhenwenoticesomethingfunnybutcan’ttolaughoutloudbecauseitwouldbeinappropriate.Also,IwillkeepsendingyoureelsaboutfootballandMeloni,norunningawayfromthat.Francesco,youhavethisuniquecombinationofbeingcare-freeandsmart.Thismakesyouoneofthemostfunpeopleinthelab.Thankyousomuchforallthefuntalkswehadonsuperrandomstuff,Iwishwecouldhavespentmoretimetogether.Hongkeng,youweremyrighthandduringmyPhD.Thanksomuchforalltheeffortyoushowedforrepairinganddesigningthecircuitsaswellasthescientificdiscussionwehad.Withoutyou,thisPhDwouldnotbepossible.Onder,wekneweachotherfromAnkarabutweweren’tclose.That’swhyI’mgladthatyoustarteddoingyourPhDinPOWERlabbecauseitgavemechancetogetyouknowyouclosely.Besidesbeingaclosefriend,youalsocomeupwiththenewcircuitdesignformyprojectandverysignificantlycontributedtomyresearcheventhoughyoudidn’thaveto,Ioweyouoneforthat.ThankyousomuchfortheeffortyoushowedformyresearchaswellasallthefuntripswehadinSwitzerland.I’malsosorryforwatchingGalatasaraygameswithyouandmakeuslose.Cankat,yourwordsandactionsareveryconsistent.Thisissomethingveryvaluableandrare,that’swhyIalwaysvaluedandrespectedyouasaclosefriend.ThankyousomuchforallocatingtimeformefromyourcrazycleanroomscheduleandbethereformewhenIsaidIneededsomeonetotalkto.I’mreallylookingforwardtoseewherethelifewilltakeyou,especiallyaspersonwhounderstandswhereyou’recomingfrombuthasadifferentmindsetcomparedtoyou.Ivan,you’rebyfarmyfavouriteBalkanpersoninthelabandIpromiseyouit’snotbecauseyou’retheonlyBalkanpersoninthelab.You’reoneofthemostgenuinepeopleIhaveeverseeninmylifeandhonestlyeveryinteractionwehadwassuperenjoyable.ThankyousomuchforeffortlesslyliftingupmymoodregardlessofhowdownIwasandcaringaboutmyproblematthesametime.Tobias,youwereright,everythingwentwell.Sorryfornotlisteningtoyouearlyanddrinkadietcoke.Yetyoustilltaughtmewhentotake

5

thingsseriouslyandwhennottoandIwillkeepthislessonwithme.Thanksforthedeliciousbreadandsavagejokes,yourfavoriteTurkishBoywillbearoundforawhile.Darléne,youwereliterallytheonlypersonwhosharedmyjoywhenIhitadeadliftorasquatPRingymandsharingthesewithyoumademeveryhappy.IhopeIalsobroughtjoytoyourdaysasyoudidformine.ThankssomuchfortheNarutogifts,fruitteaandbeingmysafespacewhenitcomestoFrench,youhelpedmealotandwithoutyouprobablyI’dbelost.Guang-Yu,wemettowardstheendofmyPhDbutIwishyouwerehereearlierasIreallyenjoyedworkingwithyouandyoureallyincreasedmyunderstandingbehindthemicro-plasmadischarges.ThankyousomuchforalwaysbeingthereforascientificdiscussionandI’mprettysurethatwewillcontinuetocollaborateinthefuture.MohammadSamizadeh,Nikoo,thanksforyourtimeandeffortsduringtheearlystagesofmyPhD,itwastrulyappreciated.Shasha,Songlan,Farzaneh,Claire,Manon,Julio,Victor,Jean,Stefaniafroméquipecitron,Rémy,Zezhong,Yildiz,Antoine,Jean,Maxime,Utku,Uiho,Weiyu,Qihao,Ibrahim,Amir,MohammadRezaei,Yuan,AnnaandAlessandro(sorryifIforgetanyone!)-thankyousomuchformakingthebothofmylabscheerful.Yourpresencemadethelabawarmandwelcomingplacetowork.LastlyKatia,thanksforbeingtherewhenevernecessary,youwerealifesaverandPOWERlabisveryluckytohaveyou.

Yasmin,youbecamemypartnerduringthelowestpointofmyPhD.Istillrememberthediscussionwehadinthecarwhenyousaid“it’sokayifyoujuststopandcomebackhome,we’llfindaway”.Honestly,thatconversionwasthereasonwhyIkeptgoingbecauseyoushowedmethistitleandmyownvalueweretwodifferentthingsandstuffgoingbaddidn’tmeanthatmyselfself-worthwasdecreasing.YourmindsetwaswhatImostlylackedandmymindsetwaswhatyoumostlylacked,soweendeduplearningalotfromeachothertobecomebetterpeopleandpartners.Thiswasalsopainfulbutyet,attheendoftheday,thelittlekidsinsideofustriedtheirbesttofindawaytokeephuggingandstayingtogether.Thankyousomuchforshowingatremendousamountofpatiencetowardsmeandtirelesslycraftingmetomakeabetterpersonandpartner,especiallyshowingmethatlovingsomeoneforwhotheyareisactuallypossible.

Mydearparents,yoursupportwasmorethantheregularphonecallswehadonMondaysand

6

Thursdays.YouliterallywentthrougheverysecondofthisPhDwithmeandfelteverythingIfelt.Iwillneverforgetthedaywesubmittheinitialdraftofmythesistogether,whereIcalledyouandsaid“Mom,dad,I’vebeenworking45hoursnon-stop.CouldyoupleasestayonthephoneandtalktomesothatIdon’tfallasleep?”.Youstayedonthephonewithmeandwewereabletosubmitmythesisintimearound6a.m.inthemorning.You’rethesecretheroesbehindthistitleI’mverygratefulandlucky

tohaveparentslikeyou.Intheend,thankGod,itworkedverywell.Thistitleisalsoforyouasmuchasit’sforme.

Thankyou,EPFL,forthejourney–fortheknowledge,thechallenges,andthegrowth.You'veshapedmeandpreparedmeforwhatcomesnext.Here'stonewbeginningsandexcitinghorizonsahead!

Lausanne,June11,2025BartuKarakurt

Abstract

7

Abstract

CO2conversionplaysavitalroleinaddressingclimatechangebycuttinggreenhousegasemissionsandpromotingacircularcarboneconomy.Ratherthanreleasingcarbondioxideintotheatmosphere,carbondioxiderecyclingtechnologiesallowstransformationofthecapturedCO2intovaluableend-productssuchasfuelsandbuildingblockmolecules.Inthiscontext,energy-efficientandelectrifiedCO2conversionoffersapromisingpathwayforcarbon-neutralchemicalproduction,asCO2capturedfromtheaircanbevalorizedbyusingfullyrenewableelectricity.ThisapproachnotonlyreducesrelianceonfossilfuelsasanenergysourcebutalsoenablestheuseofCO2asasustainablecarbonfeedstock,offeringarenewablealternativeformaterialsynthesis.

Inthiswork,wepresentanoveldevicecapableofgeneratingtunablemicro-plasmamodes(arc,pulsed,pulsedarc)onachip,enablingefficient,low-powerandscalableCO2valorization.Inthefirstpartofthethesis,weshowasimpleandscalablecleanroomfabricationmethodforproducingcompactmicro-plasmadevicesforelectrifiedCO2valorizationandinvestigatetheimpactofdevicegeometryontheCO2splitting.Detailedmicro-plasmaimageprocessingrevealsthatthemicro-plasmapulseformationexhibitsarandomnature,whichsignificantlyinfluencesreactionkinetics.Asaresult,theeffectsofrandommicro-plasmapulseformationonoverallCO2splittingkineticsaredecoupledbydevelopingsingle-sitedevices,wheretheminimizedelectrodelengthensuresthatpulsesareconfinedtoasinglespot.Extensiveexperimentalkineticstudiesconductedonthesesingle-sitedevicesrevealthatCO2splittingproceedsviaavibrationalexcitationmechanism,achievingamaximumenergyefficiencyof29%.Inaddition,thesestudiesintroducepulsedarcasanovelwayofenhancingCO2conversionwithnegligiblelosesintheefficiency,whereweshowthatsequentiallycombiningpulsedandarcplasmatriplestheCO2conversionwithonlya14.5%decreaseintheenergyefficiency.Wedemonstratethatthepeakenergyefficiencyof29%ismaintainedacrossabroadCO2conversionrange(from0.2%to21%)forplasmapowerslessthan1W–atleastanordermagnitudelowerpowerthanthesystemswithsimilarperformance.Lastly,wedemonstratedevicelife-timesreacting30hours,highlightingtherobustnessofthesystemforpotentiallong-termapplications.

8

Insecondchapter,followingtheextensiveexperimentalstudies,wedevelopacomprehensive,custom-builtcomputationalmodelinMATLABtosimulatethereactionkineticsandhaveanin-depthmechanisticunderstandingoftheunderlyingprocessesgoverningcarbondioxidedissociation.First,theeffectofrandompulseformationontheCO2splittingkineticsisinvestigatedbyusingazero-dimensional(0D)kineticmodel,inwhichtherandomnessofpulseformationwasincorporatedthroughanimage-processing-basedMonteCarlosimulation.ThekineticmodelsolelybuiltonthevibrationalexcitationmechanismrevealsthattheCOproductionrateincreasesnon-linearlywithincreasingnumberofpulsesontheserpentinepatterneddevicessincepulsesstarttooverlapmorefrequentlywhenthepulsenumberisincreased.Inaddition,themodellingeffortsalsorevealhowpulsetimingeffectstheCO2splittingreactionrate,wherethedecayobservedintheenergyefficiencyasfunctionofinter-pulsepackettime(measuredonsinglesitedevices)isattributedtothedecayingofhighlyexcitedCO2asymmetricvibrationalmodestogroundstate.

Lastly,wedemonstratetheversatilityofourdevicesthroughdryreformingmethaneandCO2hydrogenationreactions.Dryreformingofmethaneresultsrevealthatitispossibleachieve33%energyefficiencywithasyngasratiocloseto1,whichisdesirableforthesynthesisofoxygenatedchemicals.CatalyticCO2hydrogenationresultsrevealthatdepositioncoppercatalystinsidethedischargegapsignificantlyincreasesCO2hydrogenationselectivitytowardsmethanol,demonstratingthatitispossibletoincorporatecatalystswiththemicro-plasmadevices,wheretheintegrationofrobustandeasilyfabricatedcatalystsunderscoresthepotentialofourdeviceshaveforawiderangeofchemicalprocesses.

Insummary,wedevelopedanelectrifiedchemicalplatformforlow-power,energyefficientandscalablevalorizationofCO2thatcanbefullyrenewablepoweredandextendedtomanyotherchemicalreactionsuponincorporationofcatalysts.

Keywords

CO2,atmosphericpressuremicro-plasmas,nanosecondrepetitivelypulseddischarges,plasmapower,CO2splitting,dryreformingofmethane,CO2hydrogenation,cleanroomfabrication,imageprocessing.

Résumé

9

Résume

LaconversionduCO2joueunr?leessentieldanslaluttecontrelechangementclimatiqueenréduisantlesémissionsdegazàeffetdeserreetenfavorisantuneéconomiecirculaireducarbone.Plut?tquederejeterdudioxydedecarbonedansl'atmosphère,lestechnologiesderecyclagedudioxydedecarbonepermettentdetransformerleCO2captéenproduitsfinisdevaleurtelsquedescarburantsetdesmoléculesdebase.Danscecontexte,laconversionduCO2,économeenénergieetélectrifiée,offreunevoieprometteusepouruneproductionchimiqueneutreencarbone,carleCO2captédansl'airpeutêtrevaloriségraceàuneélectricitéentièrementrenouvelable.Cetteapprocheréduitnonseulementladépendanceauxcombustiblesfossilescommesourced'énergie,maispermetégalementd'utiliserleCO2commematièrepremièredurable,offrantunealternativerenouvelablepourlasynthèsedematériaux.Danscetravail,nousprésentonsunnouveaudispositifcapabledegénérerdesmodesdemicro-plasmaaccordables(arc,pulsé,arcpulsé)surunepuce,permettantunevalorisationduCO2efficace,économeenénergieetévolutive.Danslapremièrepartiedelathèse,nousprésentonsuneméthodesimpleetévolutivedefabricationensalleblanchepourlaproductiondedispositifsmicro-plasmacompactsdestinésàlavalorisationélectrifiéeduCO2etétudionsl'impactdelagéométriedudispositifsurlaséparationduCO2.Letraitementdétaillédesimagesmicro-plasmarévèlequelaformationdesimpulsionsmicro-plasmaprésenteunenaturestochastique,aléatoire,quiinfluencesignificativementlacinétiquederéactionpourdesgéométriesdedispositifsspécifiques.Parconséquent,leseffetsdelaformationaléatoiredesimpulsionsmicro-plasmasurlacinétiqueglobaledeséparationduCO2sontdécouplésendéveloppantdesdispositifsmono-site,oùlalongueurminimaledesélectrodesgarantitleconfinementdesimpulsionsàunseulendroit.Desétudescinétiquesexpérimentalesapprofondiesmenéessurcesdispositifsmono-siteontrévéléquelaséparationduCO2sefaitviaunmécanismed'excitationvibrationnelle,atteignantunrendementénergétiquemaximalde29%.Deplus,lesmêmesétudescinétiquesprésententl'arcpulsécommeunenouvelleméthodepouraméliorerlaconversionduCO2avecdespertesd'efficaciténégligeables.Nousmontronsquelacombinaisonséquentielledeplasmapulséetd'arctriplelaconversionduCO2avecunediminutiondeseulement14,5%del'efficacitéénergétique.Nousdémontronsquel'efficacitéénergétiquemaximalede29%estmaintenuesurune

10

largeplagedeconversionduCO2(de0,2%à21%)pourdespuissancesplasmainférieuresà1W,soitunepuissanceinférieured'aumoinsunordredegrandeuràcelledessystèmesauxperformancessimilaires.Enfin,nousdémontronsdesduréesdeviede30heuresderéaction,soulignantlarobustessedusystèmepourdesapplicationspotentiellesàlongterme.

Dansledeuxièmechapitre,suiteàdesétudesexpérimentalesapprofondies,nousdévelopponsunmodèleinformatiquecompletetpersonnalisédansMATLABafindesimulerlacinétiquederéactionetd'acquérirunecompréhensionmécanisteapprofondiedesprocessussous-jacentsrégissantladissociationdudioxydedecarbone.Toutd'abord,l'effetdelaformationd'impulsionsaléatoiressurlacinétiquedeséparationduCO2estétudiéàl'aided'unmodèlecinétiquezéro-dimensionnel(0D),danslequellecaractèrealéatoiredelaformationdesimpulsionsaétéintégrépardessimulationsdeMonteCarlobaséessurletraitementd'images.Lemodèlecinétique,baséuniquementsurlemécanismed'excitationvibrationnelle,révèlequeletauxdeproductionnonlinéairedeCO2observédanslesdispositifsdotésd'électrodespluslonguesestd?auchevauchementplusfréquentdesimpulsionsrésultantd'unnombreaccrud'impulsions.Nosrésultatsmontrentégalementquelemodèlecinétiquerévèleégalementl'effetdutimingdesimpulsionssurlavitessederéaction,baséuniquementsurlemécanismed'excitationvibrationnelle,cequiconcordefortementaveclesrésultatsexpérimentauxetattribueladécroissanceobservéedel'efficacitéénergétiqueenfonctiondutempsentrelespaquetsd'impulsions(mesurésurdesdispositifsmono-site)àladécroissancedesmodesvibrationnelsasymétriquesduCO2hautementexcités.

Enfin,nousdémontronslapolyvalencedenosdispositifsparlebiaisderéactionsdereformageàsecduméthaneetd'hydrogénationduCO2.Lesrésultatsdureformageàsecduméthanerévèlentqu'ilestpossibled'atteindreunrendementénergétiquede33%avecunratiodegazdesynthèseprochede1,cequiestsouhaitablepourlasynthèsedeproduitschimiquesoxygénés.Lesrésultatsdel'hydrogénationcatalytiqueduCO2révèlentqueledép?td'uncatalyseuraucuivredansl'espacededéchargeaugmentesignificativementlasélectivitédel'hydrogénationduCO2versleméthanol,démontrantainsilapossibilitéd'intégrerdescatalyseursaudispositifmicro-plasma.L'intégrationdecatalyseursrobustesetfacilesàfabriquersoulignelepotentieldecesdispositifsmicro-plasmapourunelargegammede

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procédéschimiques.Enrésumé,nousavonsdéveloppéuneplateformechimiqueélectrifiéepourlavalorisationduCO2àfaibleconsommationd'énergie,économeenénergieetévolutive,entièrementrenouvelableetextensibleàdenombreusesautresréactionschimiquesgraceàl'incorporationdecatalyseurs.

Mot-clés

CO2,micro-plasmasàpressionatmosphérique,déchargespulséesrépétitivesnanosecondes,puissance

plasma,fractionnementduCO2,reformageàsecefficaceduméthane,hydrogénationduCO2,fabricationensalleblanche.

TableofContents

12

TableofContents

LISTOFABBREVIATIONS 16

LISTOFFIGURES 18

LISTOFSUPPLEMENTARYFIGURESFORCHAPTER4

24

LISTOFSUPPLEMENTARYFIGURESFORCHAPTER5

24

LISTOFEQUATIONS

25

LISTOFTABLES

27

LISTOFSUPPLEMENTARYTABLESFORCHAPTER4

27

CHAPTER1:INTRODUCTION 28

1.1Reducingcarbonemissions 28

1.2Alternativesustainableenergyandcarbonresources 28

1.3CO2asarenewablecarbonfeedstock 29

1.4FoundationalCO2valorizationtechniques 29

1.5ElectrochemicalCO2conversion 31

1.6PlasmatechnologyforCO2conversion 33

1.6.1.Dielectricbarrierdischarge(DBD)plasma 35

1.6.2.Glidingarc(GA)plasma 37

1.6.3.Microwave(MW)plasma 38

1.6.4Nanosecondrepetitivelypulsed(NRP)dischargeplasma 38

TableofContents

13

1.7FuturedirectionsonelectrifiedCO2conversionmethods 39

1.8Foundationalworkforthisthesis 40

1.9Motivationofthisthesis 41

CHAPTER2:OBJECTIVES 43

2.1Objective1:Investigationofnanosecondrepetitivelypulsedmicro-plasmaCO2splitting 43

2.2Objective2:Developmentandresultofzero-dimensionalkineticmodel 43

2.3Objective3:Applicationofmicro-plasmadevicestootherreactions 43

CHAPTER3:EFFECTOFMICRO-PLASMADEVICEGEOMETRYAND

TUNABLEMODESONCO2SPLITTING 46

3.1Fabricationofthemicro-plasmadevices 46

3.2Fundamentalworkingprincipleofthemicro-plasmadevices 48

3.3ExperimentalsetupandcalculationoftheCOproductionrate 49

3.4EffectsofdevicegeometryontheCOproductionrate 50

3.4.1Foundationaldevicedrivingcircuit 50

3.4.2Kineticstudiesonserpentinepatterneddevices 51

3.5Single-sitemicro-plasmadeviceandsquarevoltagegeneratorforinvestigationofpulsedCO2

splittingreactionmechanism 60

3.5.1Single-sitemicro-plasmadevice 60

3.5.2Squarevoltagegenerator 62

3.6PureCO2splittingperformanceofallmicro-plasmamodesofoperation 65

3.6.1Kineticstudiesonthesingle-sitedevice 65

3.6.2.Scalabilityofsinglesitemicro-plasmadevices 70

3.7Life-timeofthemicro-plasmadevices 73

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3.8Concludingremarks 73

CHAPTER4:ZERO-DIMENSIONALKINETICMODELAND

MODELLINGRESULTS 75

4.1Zero-dimensionalkineticmodel 75

4.2Thereactionset 76

4.3Ratelaws 78

4.3.1.Vibrationalquanta-transferreactionsandneutral-neutralcollisions 78

4.3.2.Electron-impactreactions 78

4.4Estimationofthemodelparameters 80

4.4.2Electrondensity 81

4.4.3.Theoreticalestimationoftheplasmavolumeforthesingle-sitedevice 82

4.5ComputationalnumericalsolutionoftheconservationlawinMATLAB 83

4.5.1.Numericalsolutionofthereactionmatrix 83

4.5.2.ValidationoftheordinarydifferentialequationsolvercodedinMATLAB 85

4.60DKineticmodellingresults 86

4.6.1.Kineticmodelresultsforserpentinepatterndevices 86

4.6.2.Kineticmodelresultsforthesingle-sitedevice 87

4.7Concludingremarks 89

CHAPTER5:APPLICATIONOFMICRO-PLASMADEVICESTOOTHER

REACTIONS 90

5.1Non-catalyticdryreformingofmethaneunderatmosphericpressure 90

5.1.1.EffectofCO2/CH4ratiooncokeformationandsyngasratio 90

5.2CO2hydrogenationintomethanol 93

TableofContents

15

5.2.2.IncreasingtheCucatalystsurfacearea 95

5.3Concludingremarks 96

CHAPTER6:CONCLUSIONSANDOUTLOOK 98

6.1Conclusions 98

6.2Outlook 98

APPENDIXAFORCHAPTER3 100

3.1MonteCarloSimulationcode 100

APPENDIXBFORCHAPTER4 101

4.1Electronimpactreactionrateconstantscalculatedforthemodel 101

4.2Optim