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Wax ku ool ah, jaban oo waara falcelinta dhimista ogsijiinta (ORR) korantada ayaa muhiimad weyn u leh baytariyada Zn-hawada labaad.Dhaqdhaqaaqa ORR ee oksaydhyada birta ah iyo kuwa isku dhafan iyo kaarboonka elektiroonigga ah ayaa la baadhay iyada oo la adeegsanayo cabbirada korantada diskka ee wareega (RDE), jiirarka Tafel, iyo dhulalka Kutetsky-Levich.Waxaa la ogaaday in isku-dhafka MnOx iyo XC-72R ay muujinayaan waxqabadka sare ee PBP iyo xasilloonida wanaagsan, ilaa 100 mA cm-2.Waxqabadka electrodes-ka ORR ee la doortay iyo falcelinta kobaca oksijiinta ee hore loo hagaajiyay (OER) electrode ayaa markaa lagu tijaabiyay baytari hawo-hawo ah oo si gaar ah loo dhisay oo ah qaabaynta saddex-electrode, iyo cufnaanta hadda, molarity electrolyte, heerkulka, nadiifinta oksijiinta sidoo kale la tijaabiyay.Astaamaha ORR iyo OERelectrodes.Ugu dambeyntii, adkaysiga nidaamka sare ee zinc-hawada ayaa la qiimeeyay, taasoo muujinaysa waxtarka tamarta ee 58-61% at 20 mA cm-2 ee 4 M NaOH + 0.3 M ZnO at 333 K saacadaha 40.
Baytariyada birta-hawada leh electrodes ogsijiin waxaa loo arkaa habab aad u soo jiidasho leh sababtoo ah qalabka korantada ee electrodes oxygen si fudud ayaa laga heli karaa jawiga ku wareegsan oo aan u baahnayn kaydinta1.Tani waxay fududeyneysaa naqshadeynta nidaamka iyadoo u oggolaanaysa kororka oksijiinta inuu yeesho awood aan xadidneyn, taas oo kordhinaysa cufnaanta tamarta nidaamka.Sidaa darteed, baytariyada birta-hawada isticmaalaya walxaha anode sida lithium, aluminium, iron, zinc, iyo magnesium ayaa soo baxay sababtoo ah awooddooda gaarka ah ee aad u fiican.Waxaa ka mid ah, baytariyada hawada zinc waa kuwo awood u leh inay daboolaan baahida suuqa ee qiimaha, badbaadada, iyo saaxiibtinimada deegaanka, maadaama zinc uu leeyahay astaamo badan oo la jecel yahay sida walxo anode ah, sida xasilloonida wanaagsan ee electrolytes aqueous, cufnaanta tamarta sare, iyo dheellitirka hooseeya.kartidaWaqtigan xaadirka ah, inkasta oo baytariyada hawada zinc aasaasiga ah loo isticmaalo codsiyada ganacsiga sida qalabka gargaarka maqalka, calaamadaha tareenada iyo nalalka hagidda, baytariyada hawada sare ee zinc waxay awood u leeyihiin cufnaanta tamar sare oo la mid ah baytariyada lithium-ku salaysan.Tani waxay ka dhigaysaa mid mudan in la sii wado cilmi baarista ku saabsan baytariyada hawada zinc ee codsiyada elektaroonigga la qaadi karo, baabuurta korantada, kaydinta tamarta xadka iyo in la taageero wax soo saarka tamarta dib loo cusboonaysiin karo6,7.
Mid ka mid ah ujeedooyinka muhiimka ah ayaa ah in la wanaajiyo waxtarka falcelinta oksijiinta ee electrode-ka hawada, kuwaas oo ah falcelinta dhimista oksijiinta (ORR) iyo falcelinta kobcinta oksijiinta (OER), si kor loogu qaado ganacsiga baytariyada Zn-hawada sare.Si taas loo gaaro, elektrocatalysts wax ku ool ah ayaa loo isticmaali karaa si loo kordhiyo heerka falcelinta oo sidaas darteed kor loogu qaado waxtarka.Waqtigan xaadirka ah, electrodes oksijiin oo leh kicinta laba-geesoodka ah ayaa si fiican loogu sharraxay suugaanta8,9,10.Inkasta oo kicinta laba-cirifoodka ah ay fududayn karaan qaab-dhismeedka electrodes oo ay yareeyaan khasaaraha kala iibsiga badan, taas oo kaa caawin karta dhimista kharashka wax soo saarka, ficil ahaan, kicinta ku habboon ORR inta badan kuma habboona OER, iyo lidka11.Farqiga u dhexeeya awoodda hawl-qabadku wuxuu keenaa kicinta inay soo bandhigto awoodo kala duwan oo ballaadhan, taas oo beddeli karta qaab-dhismeedkeeda korka muddo ka dib.Intaa waxaa dheer, isku-tiirsanaanta tamarta isku-xirnaanta dhexdhexaadka ah waxay ka dhigan tahay in goobaha firfircoon ee kicinta ay ka duwanaan karaan falcelin kasta, taas oo adkeyn karta hagaajinta.
Dhibaato kale oo weyn ee baytariyada Zn-hawada sare waa naqshadeynta ogsijiintaelectrode, inta badan sababtoo ah kicinta monofunctional ee ORR iyo OER waxay ku shaqeeyaan warbaahin falcelineed oo kala duwan.Lakabka gaaska ORR waa inuu noqdaa biyo-cabbid si loogu oggolaado gaaska ogsijiinta inuu galo goobaha catalytic, halka OER-da dusha sare ee elektiroonigga ah ay tahay inay noqoto hydrophilic si ay u fududayso ka-saarista xumbo oksijiinta.On berde.1 waxa ay muujinaysaa saddex nashqadaha korantada oksijiinta sare ee caadiga ah oo laga soo qaatay dib u eegis uu sameeyay Jorissen12, kuwaas oo kala ah (i) kiciyayaasha monolayer bifunctional, (ii) labanlaab ama labajibbaarane, iyo (iii) isku xidhka korantada saddexlaha ah.
Naqshadaynta korantada ugu horeysa, oo ay kujirto hal lakab oo labajibbaaran oo isku mar ah oo isku mar kataliya ORR iyo OER, haddii xuubka lagu daro naqshaddan, ka dibna unug-electrode Assembly (MEA) ayaa la sameeyay sida muuqata.Nooca labaad waxaa ka mid ah laba (ama ka badan) sariiraha kicinta leh oo leh porosity kala duwan iyo hydrophobicity si loo xisaabiyo kala duwanaanshaha aagagga falcelinta13,14,15.Xaaladaha qaarkood, labada sariirood ee catalytic waa la kala soocaa, iyadoo dhinaca hydrophilic ee OER ay wajahayso electrolyte iyo dhinaca semi-hydrophobic ee ORR oo wajahaya darafyada furan ee electrodes 16, 17, 18. unug ka kooban laba falcelin- electrodes ogsijiin gaar ah iyo a zinc electrode19,20.Shaxda S1 ayaa taxaysa faa'iidooyinka iyo khasaarooyinka naqshad kasta.
Hirgelinta naqshadaynta korantada ee kala saarta falcelinta ORR iyo OER ayaa hore u muujisay xasilloonida baaskiilka19.Tani waxay si gaar ah run ugu tahay qaabaynta saddexda korantada, halkaas oo hoos u dhigista kicinta aan xasilloonayn iyo isku-darka la yareeyay oo gaaska bannaanka laga saarayo uu yahay mid la kontarooli karo dhammaan baaxadda suurtagalka ah.Sababahan dartood, waxaanu shaqadan u isticmaalnay qaabaynta Zn-hawada saddex-electrode ah.
Maqaalkan, waxaan marka hore dooranaa wax-qabad sare ORR-ga annagoo isbarbar dhig ku sameynayna oksaydhyada biraha kala-guurka ee kala duwan, agabka kaarboonka, iyo kicinta tixraaca ee leh tijaabooyinka korantada wareega (RDE).Okssaydhyada birta ah ee ku-meel-gaadhka ahi waxay u muuqdaan inay noqdaan koronto-dhaliyeyaasha wanaagsan sababtoo ah dawladahooda oksaydhka ee kala duwan;falcelinta si fudud ayaa loo kiciyaa marka ay joogaan xeryahooda21.Tusaale ahaan, oxides manganese, cobalt oxides, iyo oxides-ku-salaysan isku-dhafka ah (sida NiCo2O4 iyo MnCo2O4) 22,23,24 waxay muujinayaan ORR wanaagsan xaaladaha alkaline sababtoo ah d-orbitals-ka-buuxsan, heerarka tamarta korantada ee u oggolaanaya elektarooniga shaqada iyo hagaajinta raaxada goynta.Intaa waxaa dheer, waxay aad ugu badan yihiin deegaanka waxayna leeyihiin koronto la aqbali karo, falcelin sare iyo xasilooni wanaagsan.Sidoo kale, walxaha carbonaceous ayaa si weyn loo isticmaalaa, iyagoo leh faa'iidooyinka korantada sare ee korantada iyo bedka weyn ee dusha sare.Xaaladaha qaarkood, heteroatoms sida nitrogen, boron, fosfooraska, iyo baaruudka ayaa lagu soo bandhigay kaarboon si wax looga beddelo qaab-dhismeedkeeda, iyada oo la sii wanaajinayo sifooyinka ORR ee alaabtan.
Iyada oo ku saleysan natiijooyinka tijaabada, waxaan ku soo darnay soosaarayaasha OVR ee la doortay ee gaaska faafinta electrodes (GDE) waxaana ku tijaabinay cufnaanta hadda jirta ee kala duwan.Dhaqdhaqaaqa ORR GDE ee ugu waxtarka badan ayaa markaa la isugu geeyay caadaddayada saddexda-electrode secondary Zn-air batari oo ay weheliso falcelin-gaar ah OER electrodes oo lagu hagaajiyay shaqadeenii hore26,27.Awoodaha electrodes-ka oksijiinta ee shaqsiga ah ayaa la kormeeray inta lagu jiro sii daynta joogtada ah iyo tijaabinta baaskiil wadista si loo darso saamaynta xaaladaha hawlgalka sida cufnaanta hadda, molarity electrolyte, heerkulka hawlgalka unugyada, iyo nadiifinta oksijiinta.Ugu dambayntii, xasiloonida baytariyada labaad ee Zn-air ayaa lagu qiimeeyay baaskiil joogto ah iyadoo lagu hoos jiro xaaladaha hawlgalka ugu wanaagsan.
MnOx28 waxaa diyaariyey habka dib-u-dejinta kiimikada: 50 ml oo ah 0.04 M KMnO4 xal (Fisher Scientific, 99%) ayaa lagu daray 100 ml 0.03 M Mn (CH3COO) 2 (Fisher Scientific, 98%) si ay u sameeyaan roobaad bunni ah.Isku darka waxaa lagu hagaajiyaa pH 12 iyadoo lagu qasi karo sodium hydroxide, ka dibna centrifuge 3-5 jeer 2500 rpm si loo ururiyo roobka.Da'da ayaa markaa lagu maydhay biyo deionized ilaa midabka guduudan ee ion permanganate uu meesha ka baxay.Ugu dambeyntii, kaydka ayaa hawo lagu qallajiyey 333K habeenba ka dibna la miiray.
Spinel oxides Co3O4, NiCo2O4, iyo MnCo2O4 ayaa lagu soo koobay kuleyl.NiCo2O4 iyo MnCo2O4 ayaa la diyaariyey iyadoo lagu daray 0.5 M (14.5 g) nikkel (II) nitrate hexahydrate, Ni (NO3) 2⋅6H2O (Fisher Scientific, 99.9%) ama 0.5 M (12.6 g) tetrahydrate manganese (II) NO3 nitrate min ).)2 4H2O (Sigma Aldrich, ≥ 97%) iyo 1 M (29.1 g) cobalt(II) nitrate hexahydrate, Co(NO3)2 6H2O (Fisher Scientific, 98+%, ACS reagents) ee methanol (Fisher Scientific, 99.9%) ) 100 ml oo fijaan ah oo lagu qasi karo.Methanol waxaa lagu daraa qaybo yar yar oo ah nitrate-ka birta kala-guurka iyadoo la walaaqayo si joogto ah ilaa xal isku mid ah laga helayo.Xalka ayaa markaa loo wareejiyay weel oo kuleyl kuleyl kuleyl ah, ka tagista casaan madow oo adag.Qalabka adag waxaa lagu dhajiyay 648 K 20 saacadood oo hawo ah.Aadka ka soo baxay ayaa markaa lagu rusheeyey budo fiican.Maya Ni(NO3)2 6H2O ama Mn(NO3)2 4H2O ayaa lagu daray inta lagu guda jiro isku dhafka Co3O4.
Graphene nanosheets oo leh aagga dusha sare ee 300 m2 / g (Sigma Aldrich), graphene lagu dhejiyay nitrogen (Sigma Aldrich), budada madow ee carbon (Vulcan XC-72R, Cabot Corp., 100%), MnO2 (Sigma Aldrich) iyo 5 wt.% Pt/C (Acros Organics) ayaa loo isticmaalay sidii hore.
RDE (Qalabka Cilmi-baarista Pine) cabbirada ayaa loo isticmaalay si loo qiimeeyo dhaqdhaqaaqa kicinta ORR ee kala duwan ee 1 M NaOH.Khad katalytik ah oo ka kooban 1 mg kicinta + 1 ml deionized (DI) H2O + 0.5 ml isopropanol (IPA) + 5 µl 5 wt% Nafion 117 (Sigma-Aldrich) ayaa loo isticmaalay sidii hore.Markii Vulcan XC-72R lagu daray, rinjiga catalytic wuxuu ka kooban yahay 0.5 mg kicinta + 0.5 mg Vulcan XC-72R + 1 ml DI HO + 0.5 ml IPA + 5 µl 5 wt% Nafion 117 si loo hubiyo rarida walxaha joogtada ah.Isku dar ah ayaa la sonicated 20 daqiiqo iyo homogenized isticmaalaya a Cole-Parmer LabGen 7 Series homogenizer at 28,000 rpm 4 daqiiqo.Khadkii ayaa markaa lagu dabaqay saddex qaybood oo 8 μl ah oogada korantada kaarboonka ee muraayadda leh (Shirkadda Pine Instrument Company) oo leh dhexroor 4 mm (aagga shaqada ≈ 0.126 cm2) waxaana la qalajiyey inta u dhaxaysa lakabyada si loo bixiyo culeyska ≈120 μg cm -2.Inta u dhaxaysa codsiyada, dusha sare ee kaarboonka kaarboonka muraayadda ah ayaa si isdaba joog ah u qooyay MicroCloth (Buehler) iyo 1.0 mm iyo 0.5 mm budada alumina (MicroPolish, Buehler) oo ay ku xigto sonication ee H2O.
Muunada korantada faafinta gaaska ORR waxaa loo diyaariyey si waafaqsan borotokoolkayagii hore28.Marka hore, budada kicinta iyo Vulcan XC-72R ayaa lagu daray 1: 1 miisaanka miisaanka.Kadib isku darka xalalka polytetrafluoroethylene (PTFE) (60 wt.% ee H2O) iyo dareere leh saamiga IPA / H2O ee 1: 1 ayaa lagu daray isku dhafka budada qalalan.Sonicate rinjiga catalytic ee ku saabsan 20 daqiiqo iyo homogenize ilaa 4 daqiiqo at 28,000 rpm.Khadkii ayaa markaas si khafiif ah loogu mariyay spatula oo lagu dul dhejiyay warqad kaarboon ah oo horay loo gooyay 13 mm dhexroor ah (AvCarb GDS 1120) oo la engejiyay ilaa nuxurka 2 mg cm2 la gaaray.
Electrodes-ka OER waxa lagu sameeyay katoodic electrodeposition of Ni-Fe hydroxide kicinta birta 15mm x 15 mmmesh(DeXmet Corp, 4SS 5-050) sida la sheegay 26,27.Electrodeposition-ka waxaa lagu sameeyay unug nus-unug ah oo saddex-electrode ah (unug dhalo ah oo polymer-dahaarka leh oo ku dhow 20 cm3) oo leh shabagga Pt oo ah korantada counter-ka iyo Hg/HgO ee 1 M NaOH oo ah koronto tixraac ah.U ogolow shabagga birta dahaarka leh ee dahaarka leh inuu hawo engejiyo ka hor inta aan la jarin aag qiyaastii 0.8 cm2 ah oo leh 10 mm dhumuc weyn oo birta birta ah.
Marka la barbardhigo, ORR-ga ganacsiga iyo korantada OER ayaa loo isticmaalay sidii la helay oo lagu tijaabiyey isla shuruudo.Electrode-ka ganacsiga ee ORR (QSI Nano Gas Diffusion Electrode, Quantum Sphere, 0.35 mm dhumuc) wuxuu ka kooban yahay manganese iyo carbon oxide oo lagu dahaadhay ururiyaha hadda jira ee nikkel, halka korantada ganacsiga OER (nooca 1.7, Magneto anode gaar ah, BV) uu leeyahay dhumuc 1.3 mm.ilaa 1.6 mm mesh tiitanium balaadhiyay oo lagu dahaadhay Ru-Ir oksaydh bir ah oo isku qasan.
Qaab-dhismeedka dusha sare iyo ka koobnaanta kicinta waxa lagu sifeeyay iyadoo la isticmaalayo FEI Quanta 650 FEG scanning microscope (SEM) oo ku hoos shaqaynaysa faakuum sare iyo danab dardargelinaya 5 kV.Xogta X-ray ee budada ah (XRD) ayaa lagu soo ururiyay Bruker D8 Advance X-ray diffractometer oo leh isha tuubada naxaasta ah (λ = 1.5418 Å) waxaana lagu falanqeeyay iyadoo la isticmaalayo Bruker Diffraction Suite EVA software.
Dhammaan cabbiraadaha korantada kiimikaad ayaa la sameeyay iyadoo la adeegsanayo Biologic SP-150 potentiostat iyo software EC-lab.Tusaalooyinka RDE iyo GDE waxaa lagu tijaabiyay jaangooyooyin saddex-electrode ah oo ka kooban 200 cm3 unug dhalo ah oo jaakad leh iyo Laggin capillary oo ah koronto tixraac ahaan.Mesh Pt iyo Hg/HgO ee 1 M NaOH ayaa loo isticmaalay korantada tixraaca, siday u kala horreeyaan.
Qiyaasta RDE ee tijaabo kasta, 1 M NaOH elektrolyt oo cusub ayaa la isticmaalay, heerkulka kaas oo si joogto ah loogu hayay 298 K iyadoo la isticmaalayo qubeyska biyaha wareega (TC120, Grant).Ogsajiinta gaaska ah (BOC) ayaa ku dhex xumbaynaysay elektrolytka iyada oo loo marayo shiillo dhalo ah oo leh dalool dhan 25–50 µm ugu yaraan 30 daqiiqo kahor tijaabo kasta.Si loo helo qaloocyada kala-soocidda ORR, awoodda ayaa laga baadhay 0.1 ilaa -0.5 V (marka loo eego Hg/HgO) qiyaasta iskaanka ee 5 mV s -1 at 400 rpm.Voltammograms wareeg ah ayaa lagu helay iyadoo la xaaqayo awoodda u dhaxaysa 0 iyo -1.0 V iyo Hg/HgO oo ah 50 mV s-1.
Qiyaasta HDE, 1 M NaOH elektrolytka waxaa lagu hayaa 333 K oo leh qubeyska biyaha wareega.Aagga firfircoon ee 0.8 cm2 ayaa la soo bandhigay elektrolytka oo leh sahayda joogtada ah ee ogsijiinta dhinaca dambe ee korantada ee heerka 200 cm3 / min.Masaafada go'an ee u dhaxaysa electrode shaqeeya iyo electrode tixraaca ahaa 10 mm, iyo masaafada u dhaxaysa electrode shaqeeya iyo electrode counter ahaa 13-15 mm.Xadhkaha nikelka iyo meshku waxay bixiyaan xidhiidhka korantada ee dhinaca gaaska.Cabbirrada Chronopotentiometric ayaa lagu qaaday 10, 20, 50 iyo 100 mA cm-2 si loo qiimeeyo xasilloonida iyo waxtarka korantada.
Sifooyinka korantada ORR iyo OER waxaa lagu qiimeeyay unug dhalada ah oo jaakadaysan oo dhan 200 cm3 lehna PTFE29 gelin.Jaantus shaxeedka nidaamka ayaa lagu muujiyay sawirka S1.Electrodes-ka ku jira baytarigu waxa ay ku xidhan yihiin hab saddex-electrode ah.Electrode-ka shaqeeyaa wuxuu ka kooban yahay falcelin gaar ah oo ORR iyo OER electrodes oo ku xidhan moduleka gudbinta (Songle, SRD-05VDC-SL-C) iyo microcontroller (Raspberry Pi 2014© model B+V1.2) oo leh zinc anode.Labbad ahaan Electrodes-ka iyo koltarka tixraaca ee Hg/HgO ee 4 M NaOH waxay u jireen masaafo 3 mm u jirta zinc anode.Farta Python ayaa loo qoray si loogu shaqeeyo loona xakameeyo Raspberry Pi iyo Module Relay.
Unugga ayaa wax laga beddelay si uu u dejiyo anode foil zinc ah (Goodfellow, dhumucdiisuna tahay 1 mm, 99.95%) iyo daboolka polymer-ka ayaa oggolaaday in korantada la dhigo meel fog oo go'an oo ku dhow 10 m.4 mm u dhexeeya.Xirmooyinka Nitrile waxay hagaajiyeen korantada daboolka, iyo fiilooyinka nikkel (Alfa Aesar, dhexroorka 0.5 mm, annealed, 99.5% Ni) ayaa loo isticmaalay xiriirada korantada ee korantada.Anode foil zinc ayaa markii hore lagu nadiifiyey isopropanol ka dibna biyo deionized, iyo dusha bireed waxaa lagu daboolay cajalad polypropylene ah (Avon, AVN9811060K, 25 µm qaro weyn) si loo soo bandhigo aag firfircoon oo ku dhawaad ​​0.8 cm2.
Dhammaan tijaabooyinka baaskiilka waxaa lagu sameeyay 4 M NaOH + 0.3 M ZnO electrolyte at 333 K ilaa si kale loo xuso.Jaantuska, Ewe marka loo eego Hg/HgO waxa ay tilmaamaysaa awoodda korantada oksijiinta (ORR iyo OER), Ece marka la eego Hg/HgO waxa ay u taagan tahay awoodda korantada zinc, Ecell marka la eego Hg/HgO waxa ay u taagan tahay buuxda awoodda unugga ama farqiga iman kara.inta u dhaxaysa laba awood oo batari.Ogsajiinta ama hawo cufan ayaa la siiyay dhinaca dambe ee korantada OPP iyadoo xawaare joogta ah 200 cm3/daqiiqo ah.Xasiloonida baaskiilka iyo waxqabadka korantada waxaa lagu bartay cufnaanta hadda ee 20 mA cm-2, wakhti wareeg ah oo ah 30 min, iyo wakhtiga nasashada OCV ee 1 min inta u dhaxaysa wareeg kasta oo badh ah.Ugu yaraan 10 wareeg ayaa la sameeyay imtixaan kasta, waxaana xogta laga soo saaray wareegyada 1, 5, iyo 10 si loo go'aamiyo xaaladda electrodes-ka waqti ka dib.
Qaab-dhismeedka ORR ee kicinta waxaa lagu gartaa SEM (Jaantus. 2), iyo cabbirada kala-duwanaanta raajada budada ayaa xaqiijiyay qaabka crystal ee shaybaarada (Jaantus. 3).Halbeegyada qaabdhismeed ee muunadaha kicinta waxa lagu bixiyay shaxda 1. 1. Marka la is barbar dhigo ogsaydhyada manganese, ganacsiga MnO2 ee fig.2a waxay ka kooban tahay qaybo waaweyn, iyo qaabka kala duwanaanshiyaha ee Jaantuska 3a waxay u dhigantaa JCPDS 24-0735 ee tetragonal β-MnO2.Taas lidkeeda, dusha MnOx ee Jaantuska 2b waxay muujinaysaa qaybo yaryar iyo kuwo aad u fiican, taas oo u dhiganta qaabka kala-duwanaanta ee sawirka 66 ° waxay u dhigantaa meelaha ugu sarreeya (110), (220), (310), (211), iyo (541) ee tetrahedrally xuddun u ah α-MnO2 hydrate, JCPDS 44-014028.
(a) MnO2, (b) MnOx, (c) Co3O4, (d) NiCo2O4, (e) MnCo2O4, (f) Vulcan XC-72R, (g) graphene, (h) graphene nitrogen doped, (iyo) 5 wt .% PT/C.
Qaababka raajada ee (a) MnO2, (b) MnOx, (c) Co3O4, (d) NiCo2O4, (e) MnCo2O4, (f) Vulcan XC-72R, graphene nitrogen-doped iyo graphene, iyo (g) 5 % platinum/kaarboon.
On berde.2c-e, qaab-dhismeedka dusha sare ee oksaydhyada ee ku salaysan cobalt Co3O4, NiCo2O4, iyo MnCo2O4 waxay ka kooban yihiin kooxo qaybo aan caadi ahayn.On berde.3c–e waxay muujinayaan in dhammaan kala-guuradanbirahaoksaydhisku waxay leeyihiin qaab-dhismeed laf-dhabarta iyo nidaamka crystal cubic la mid ah (JCPDS 01-1152, JCPDS 20-0781, iyo JCPDS 23-1237, siday u kala horreeyaan).Tani waxay muujinaysaa in habka kala-goynta kulaylku uu awood u leeyahay inuu soo saaro oksaydhyada birta ah ee crystalline, taas oo caddaynaysa meelaha ugu sarreeya ee si fiican loo qeexay ee qaabka kala-duwanaanta.
Sawirada SEM ee alaabta kaarboonku waxay muujinayaan isbeddelo waaweyn.On berde.2f Vulcan XC-72R kaarboon madow wuxuu ka kooban yahay nanoparticles cufan oo cufan.Taa lidkeeda, muuqaalka graphene ee Jaantuska 2g waa taargooyin aad u khalkhalsan oo leh xoogaa agglomerations ah.Si kastaba ha ahaatee, N-doped graphene (Jaantus. 2h) waxay u muuqataa inay ka kooban tahay lakabyo khafiif ah.Qaababka kala-duwanaanshaha raajada ee u dhigma ee Vulcan XC-72R, nanosheets graphene ganacsi, iyo graphene N-doped ee berdihii.3f waxay muujinaysaa isbeddelo yaryar oo ku yimaadda 2θ qiyamka (002) iyo (100) ugu sarreeya ee kaarboonka.Vulcan XC-72R waxaa loo aqoonsaday inuu yahay garaafka laba geesoodka ah ee JCPDS 41-1487 oo leh meelaha ugu sarreeya (002) iyo (100) oo ka muuqda 24.5° iyo 43.2° siday u kala horreeyaan.Sidoo kale, (002) iyo (100) ugu sarreeya ee graphene N-doped waxay ka muuqdaan 26.7° iyo 43.3°, siday u kala horreeyaan.Xoogagga asalka ah ee lagu arkay qaababka kala-duwanaanshaha raajada ee Vulcan XC-72R iyo graphene nitrogen-doped waxaa sabab u ah dabeecadda aadka u khalkhalsan ee walxahan ku jira qaab-dhismeedka dusha sare.Taas bedelkeeda, qaabka kala-duwanaanshaha ee nanosheets graphene waxay muujinaysaa fiiqan, ugu sarreeya (002) ee 26.5 ° iyo ugu sarreysa yar oo ballaaran (100) ee 44 °, taas oo muujinaysa dabeecad crystalline badan oo muunaddan ah.
Ugu dambeyntii, in fig.Sawirka 2i SEM ee 5 wt.% Pt/C wuxuu muujinayaa jajabyo kaarboon usha u eg oo leh meelo wareeg ah.Cubic Pt waxaa lagu go'aamiyaa inta badan meelaha ugu sarreeya 5 wt% Pt/C qaabka kala duwanaanshiyaha ee Jaantuska 3g, iyo meesha ugu sarreysa ee 23° waxay u dhigantaa (002) ugu sarreeya ee kaarboonka jira.
Xakamaynta toosan ee ORR ee Voltammogram ayaa lagu duubay xadiga xaaqidda 5 mV s-1.Xadidaada wareejinta tirada badan awgeed, maabyada la ururiyay (Jaantus. 4a) waxay inta badan leeyihiin qaab S-ballaaran oo fidsan oo leh awood taban.Cufnaanta xaddidan ee hadda jirta, jL, suurtogalnimada E1/2 (halka j/jL = ½) iyo kartida bilawga ah ee -0.1 mA cm-2 ayaa laga soo saaray meelahan oo lagu taxay Shaxda 2. Waxaa xusid mudan in berdaha.4a, kicinta waxaa loo kala saari karaa iyadoo loo eegayo awoodooda E1/2: (I) oksidheedh bir ah, (II) walxaha carbonaceous, iyo (III) biraha sharafta leh.
Voltammograms xaaqid toosan oo ah (a) kicinta iyo (b) filim khafiif ah oo kicin ah iyo XC-72R, oo lagu qiyaasay RDE kaarboonka muraayada leh ee 400 rpm oo leh qiyaasta 5 mV s-1 ee saturation O2 ee 298 K gudaha 1 M NaOH cf.
Okssaydhyada birta ah ee shakhsi ahaaneed ee Mn iyo Co ee kooxda I ayaa muujinaya awoodaha bilowga ah ee -0.17 V iyo -0.19 V siday u kala horreeyaan, iyo E1 / 2 qiimaha waxay u dhexeeyaan -0.24 iyo -0.26 V. .(1) iyo (2), kuwaas oo ka muuqda ku xiga awoodda bilawga ah ee ku jirta Fig.4a waafaqaya awooda caadiga ah ee talaabada koowaad 2e ee dariiqa dadban ee ORR ee isla'egta.(3).
Okssaydhka birta ah ee isku dhafan ee MnCo2O4 iyo NiCo2O4 ee isla kooxda ah ayaa muujinaya awoodaha bilowga ah ee la saxay ee -0.10 iyo -0.12 V siday u kala horreeyaan, laakiin waxay hayaan qiimaha E1/2 ee ku saabsan 10.-0.23 volts.
Kooxda II Qalabka kaarboonku waxay muujinayaan qiimayaal E1/2 oo togan marka loo eego kooxda I.Maaddada Graphene waxay leedahay awoodda bilowga ah ee -0.07 V iyo E1/2 qiimaha -0.11 V, halka awoodda bilowga ah iyo E1/2 ee 72R Vulcan XC- yihiin -0.12V iyo -0.17V siday u kala horreeyaan.Kooxda III, 5 wt% Pt/C waxay muujisay awoodda bilowga ah ee ugu wanaagsan ee 0.02 V, E1 / 2 of -0.055 V, iyo xadka ugu badan ee -0.4 V, maadaama dhimista oksijiin ay ku dhacday cufnaanta hadda ee waddada 4e .Waxa kale oo ay leedahay E1/2 ugu hooseeya sababtoo ah dhaqdhaqaaqa sare ee Pt/C iyo dhaqdhaqaaqa dib loo rogi karo ee falcelinta ORR.
Jaantuska S2a wuxuu soo bandhigayaa falanqaynta jiirada Tafel ee kicinta kala duwan.Gobolka kinetically kantaroolka ah ee 5 wt.% Pt/C wuxuu ka bilaabmaa 0.02 V marka loo eego Hg/HgO, halka gobolka oksaydhyada birta ah iyo walxaha kaarboonku ay ku jiraan kala duwanaanshaha awoodaha taban min -0.03 ilaa -0.1 V. Qiimaha jiirada loogu talagalay Tafel Pt/C waa -63.5 mV ss-1, taas oo caadi u ah Pt cufnaanta hadda hooseeya deE/d log i = -2.3 RT/F31.32 taas oo heerka-go'aaminta tallaabada ay ku lug leedahay kala-guurka oksijiinta ka soo baxa jir-dhiska kiimikaad33,34.Qiimaha jiirada Tafel ee alaabta kaarboonku waxay ku yaalliin isla gobolka Pt/C (-60 ilaa -70 mV div-1), iyagoo soo jeedinaya in walxahan ay leeyihiin wadooyin ORR la mid ah.Okssaydhyada birta ah ee shakhsiga ah ee Co iyo Mn waxay soo tebiyaan Tafel jiirarrada u dhexeeya -110 ilaa -120 mV dec-1, taas oo ah dE/d log i = -2.3 2RT/F, halkaas oo tallaabada-go'aaminta heerka ay tahay elektarooniga ugu horreeya.wareejinta tallaabada 35, 36. Qiimaha jiirada yara sare ee loo duubay oxides biraha isku qasan NiCo2O4 iyo MnCo2O4, oo ku saabsan -170 mV dec-1, muujinaysaa joogitaanka OH- iyo H2O ions on dusha oksaydhka, taas oo ka hortagtaa adsorption oxygen iyo wareejinta elektarooniga ah, taas oo saamaynaysa ogsijiinta.Jidka dhimista 35.
Isla'egta Kutetsky-Levich (KL) ayaa loo isticmaalay si loo go'aamiyo cabbirrada falcelinta kanetic ee muunado kicinta kala duwan iyada oo aan la wareejin tiro badan.ee isla'egta.(4) wadarta guud ee cufnaanta hadda la qiyaasay j waa wadarta cufnaanta hadda ee wareejinta elektarooniga iyo wareejinta tirada badan.
laga bilaabo isla'egta.(5) Cufnaanta xaddidan ee hadda jL waxay la mid tahay xididka labajibbaaran ee xawaaraha wareegga.Sidaa darteed, isla'egta KL.(6) wuxuu qeexayaa garaafka xariiqda j−1 ee ka soo horjeeda ω−1//2, halkaasoo barta isgoysku ay tahay jk, jiirada garaafkana uu yahay K.
halka ν ay tahay viscosity kinematic ee elektrolytka 1 M NaOH (1.1 × 10–2 cm2 s–1)37, D waa iskudarka faafinta O2 ee 1 M NaOH (1.89 × 10 – 5 cm2 s – 1) 38, ω rpm waa xawaaraha wareega, C waa fiirsashada ogsijiinta ee xalka guud (8.4 × 10-7 mol cm-3)38.
Uruuri voltammograms toosan oo la xaaqay adoo isticmaalaya RDE 100, 400, 900, 1600, iyo 2500 rpm.Qiimaha ayaa laga soo qaatay -0.4 V ee gobolka wareejinta tirada xaddidan si loo sawiro jaantuska KL, ie -j-1 oo ka soo horjeeda ω-1//2 ee kicinta (Jaantus. S3a).Isticmaal isla'egyadaIsla'egyada (6) iyo (7), tilmaamayaasha waxqabadka ee kicinta, sida cufnaanta hadda jirta iyada oo aan la tixgalinayn saamaynta wareejinta ballaaran ee jk, waxaa lagu go'aamiyaa barta isgoysyada dhidibka y, iyo tirada wareejinta elektarooniga waxaa lagu go'aamiyaa gradient K ee qalooca.Waxay ku taxan yihiin shaxda 2.
5 wt% Pt/C iyo XC-72R waxay leeyihiin qiyamka jk ee ugu hooseeya, taas oo muujinaysa kinetics-ka degdega ah ee alaabtan.Si kastaba ha ahaatee, jiirada qalooca XC-72R waxay ku dhowdahay labanlaab in 5 wt% Pt/C, taas oo la filayo tan iyo K waa tilmaanta tirada elektaroonigga ah ee la wareejiyo inta lagu jiro falcelinta dhimista oksijiinta.Aragti ahaan, goobta KL ee 5 wt% Pt/C waa in ay ka gudubtaa asalka 39 iyada oo la raacayo shuruudaha wareejinta ballaaran ee xaddidan, si kastaba ha ahaatee tani laguma arkin Jaantuska S3a, oo soo jeedinaya xaddidaadaha dhaqdhaqaaqa ama faafinta ee saameeya natiijooyinka.Tani waxay noqon kartaa sababtoo ah Garsani et al.40 ayaa muujiyay in is-khilaafyada yar yar ee topology-ga iyo qaab-dhismeedka filimada Pt/C catalytic ay saameyn karaan saxnaanta qiyamka waxqabadka ORR.Si kastaba ha noqotee, maadaama dhammaan filimada kicinta loo diyaariyey si isku mid ah, saameyn kasta oo natiijooyinka ku yeelanayaan waa inay isku mid noqdaan dhammaan shaybaarrada.Dhibcaha graphene KL ee ≈ -0.13 mA-1 cm2 waxay la mid tahay kan XC-72R, laakiin -0.20 mA-1 cm2 barta iskutallaabta ee garaafka graphene ee N-doped graphene KL waxay muujineysaa in cufnaanta hadda jirta ay ka weyn tahay waxay kuxirantahay danabka ku jira beddelaha catalytic.Tani waxay sabab u tahay xaqiiqda ah in doping nitrogen ee graphene ay hoos u dhigto guud ahaan dhaqdhaqaaqa korantada, taas oo keentay in dhaqdhaqaaqa wareejinta elektaroonigga ah uu yaraado.Taas bedelkeeda, qiimaha K ee buuxa ee graphene-ka nitrogen-doped ayaa ka yar kan graphene sababtoo ah joogitaanka nitrogen wuxuu caawiyaa abuurista goobo firfircoon oo badan ORR41,42.
Wixii oksaydhyada ku salaysan manganese, barta is-goysyada ee qiimaha ugu weyn ayaa lagu arkay - 0.57 mA-1 cm2.Si kastaba ha ahaatee, qiimaha K ee buuxa ee MnOx aad ayuu uga hooseeyaa kan MnO2 wuxuuna ku dhow yahay 5 wt %.%Pt/C.Tirooyinka wareejinta elektarooniga waxaa lagu go'aamiyay inay qiyaastii yihiin.MnOx waa 4 iyo MnO2 waxay ku dhowdahay 2. Tani waxay la socotaa natiijooyinka lagu daabacay suugaanta, kuwaas oo soo sheegaya in tirada wareejinta elektaroonigga ah ee waddada α-MnO2 ORR ay tahay 4, halka β-MnO243 ay caadi ahaan ka yar tahay 4. Sidaa darteed , Wadooyinka ORR waxay ku kala duwan yihiin noocyada polymorphic ee kala duwan ee kicinta ku salaysan manganese oxide, in kasta oo heerarka tillaabooyinka kiimikaad ay sii ahaanayaan ku dhawaad ​​isku mid.Gaar ahaan, MnOx iyo MnCo2O4 kicinta waxay leeyihiin lambarada wareejinta elektaroonigga ah wax yar ka sarreeya 4 sababtoo ah hoos u dhigista oksijiinta manganese ee ku jirta kiciyayaashan ayaa isku mar ku dhaca dhimista ogsijiinta.Shaqadii hore, waxaan ogaanay in dhimista korantada ee oksijiinta manganese ay ku dhacdo isla baaxadda suurtagalka ah ee hoos u dhigista oksijiinta ee xalka ku jira nitrogen28.Wax ku biirinta falcelinta dhinacyadu waxay keentaa tiro la xisaabiyay oo elektaroonig ah oo inyar ka badan 4.
Isgoysyada Co3O4 waa ≈ -0.48 mA-1 cm2, taas oo ka yar taban marka loo eego labada nooc ee oksijiinta manganese, iyo lambarka wareejinta elektaroonigga ee muuqda waxaa lagu go'aamiyaa qiimaha K oo la mid ah 2. Bedelida Ni ee NiCo2O4 iyo Mn ee MnCo2O4 by Co waxay keenaysaa hoos u dhac ku yimaadda qiyamka saxda ah ee K, taas oo muujinaysa horumar ku yimaadda kinetics wareejinta elektarooniga ah ee oksaydhyada biraha isku dhafan.
Substrate-ka kaarboonka ayaa lagu daraa khad kicinta ORR si loo kordhiyo dhaqdhaqaaqa korantada oo loo fududeeyo samaynta xuduudka saxda ah ee saddexda weji ee korantada faafinta gaaska.Vulcan-XC-72R waxaa lagu doortay qiimaha hooseeya, bedka weyn ee 250 m2 · g-1, iyo iska caabin hoose ee 0.08 ilaa 1 Ω · cm44.45.Goob LSV ah oo muunad kicinaysa lagu qasay Vulcan XC-72R at 400 rpm ayaa lagu muujiyay sawirka 1. 4b.Saamaynta ugu cad ee ku darista Vulcan XC-72R waa in la kordhiyo cufnaanta ugu dambeysa.Ogsoonow in tani ay aad uga muuqan karto oksaydhyada birta, oo leh 0.60 mA cm-2 dheeraad ah oo ah oksijiinta birta ah, 0.40 mA cm-2 ee oksaydhyada birta ah ee isku dhafan, iyo 0.28 mA cm-2 ee graphene iyo doped graphene.N. Ku dar 0.05 mA cm-2.-2.Ku darida Vulcan XC-72R ee khad kicinta waxay sidoo kale keentay isbeddel togan ee suurtagalnimada bilawga ah iyo awoodda E1/2 ee nus-mawjadaha ee dhammaan kiciyaasha marka laga reebo graphene.Isbeddelladani waxay noqon karaan natiijada suurtogalka ah ee korodhka isticmaalka aagga korantada kiimikaad46 iyo hagaajinta xidhiidhka47 ee u dhexeeya qaybaha kicinta ee Vulcan XC-72R ee la taageeray.
Sirqadaha Tafel ee u dhigma iyo halbeegyada kinetic ee isku darka kicinta ayaa lagu muujiyey Jaantuska S2b iyo Shaxda 3, siday u kala horreeyaan.Qiimaha jiirada Tafel waxay la mid ahaayeen MnOx iyo qalabka graphene oo leh iyo la'aanteed XC-72R, taasoo muujinaysa in dariiqyadooda ORR aan la taaban.Si kastaba ha noqotee, oxides-ku-saleysan Co3O4, NiCo2O4 iyo MnCo2O4 waxay siiyeen qiyam yar oo taban oo Tafel ah oo u dhexeeya -68 iyo -80 mV dec-1 oo ay weheliso XC-72R oo tilmaamaysa isbeddel ku yimaadda dariiqa ORR.Jaantuska S3b waxa uu tusinayaa goob KL ee muunad kicinaysa oo lagu daray Vulcan XC-72R.Guud ahaan, hoos u dhac ku yimid qiyamka buuxda ee jk ayaa lagu arkay dhammaan kicinta isku dhafan ee XC-72R.MnOx waxay muujisay hoos u dhaca ugu weyn ee qiimaha saxda ah ee jk 55 mA-1 cm2, halka NiCo2O4 ay diiwaangelisay hoos u dhac 32 mA-1 cm-2, iyo graphene waxay muujisay hoos u dhaca ugu yar ee 5 mA-1 cm2.Waxaa lagu soo gabagabeyn karaa in saameynta Vulcan XC-72R ee waxqabadka kicinta ay xaddidan tahay waxqabadka bilowga ah ee kicinta marka la eego OVR.
Vulcan XC-72R ma saameynayso qiyamka K ee NiCo2O4, MnCo2O4, graphene, iyo graphene nitrogen-doped.Si kastaba ha ahaatee, qiimaha K ee Co3O4 ayaa si weyn hoos ugu dhacay marka lagu daro Vulcan XC-72R, taas oo muujinaysa kororka tirada elektaroonigga ah ee uu wareejiyo ORR.Isku-xidhka noocan oo kale ah ee Co3O4 ee leh qaybaha kaarboonka ayaa lagu sheegay tixraacyo.48, 49. Maqnaanshaha taageerada kaarboonka, Co3O4 waxaa loo maleynayaa in ay kor u qaaddo isku-dheellitirnaanta HO2- ilaa O2 iyo OH-50.51, taas oo si fiican ula heshisa Co3O4 ee lambarka wareejinta elektaroonigga ah ee ku saabsan 2 ee Shaxda 2. Sidaa darteed, Xayeysinta jirka ee Co3O4 ee substrates kaarboon ayaa la filayaa inay dhaliso 2 + 2 afar-elektarooni ORR dariiqa52 kaas oo marka hore korantada ka dhigaya O2 ilaa HO2- marka la isku xidho Co3O4 kicinta iyo Vulcan XC-72R (isla'egta 1) ka dibna HO2 - Si degdeg ah u qaybsan Dusha oksaydhka birta ah ayaa loo beddelaa O2 oo ay ku xigto koronto-soo-saarka.
Taas bedelkeeda, qiimaha saxda ah ee K MnOx ayaa kordhay iyada oo lagu daray Vulcan XC-72R, taas oo ka dhigan hoos u dhaca lambarka wareejinta elektaroonigga ah ee 4.6 ilaa 3.3 (Shaxda 3).Tan waxa u sabab ah joogitaanka laba goobood oo ku yaala kaarboonka isku-darka kaarboonka ee marinka laba-heer ee elektarooniga ah.Hoos-u-dhimista hore ee O2 ilaa HO2- waxay si fudud ugu dhacdaa taageerada kaarboonka, taasoo keentay in wax yar la kordhiyo doorbidka labada-elektrooniga ah ee ORR53.
Xasiloonida kicinta ayaa lagu qiimeeyay unugga nuska GDE ee kala duwanaanshaha cufnaanta hadda.On berde.5 waxay tusinaysaa qorshayaal suurtagal ah oo ka duwan wakhtiga GDE MnOx, MnCo2O4, NiCo2O4, graphene, iyo graphene nitrogen-doped.MnOx waxay muujinaysaa xasillooni guud oo wanaagsan iyo waxqabadka ORR ee cufnaanta hoose iyo sare ee hadda jira, taasoo soo jeedinaysa inay ku habboon tahay hagaajin dheeraad ah.
Chronopotentiometry ee muunadaha HDE ee hadda laga bilaabo 10 ilaa 100 mA/cm2 gudaha 1 M NaOH, 333 K, O2 heerka socodka 200 cm3/daqiiqo.
MnCo2O4 waxa kale oo ay u muuqataa in ay xajisanayso xasiloonida ORR ee inta kala duwan ee cufnaanta hadda jirta, laakiin cufnaanta hadda sare ee 50 iyo 100 mA cm-2 xad-dhaafka weyn ayaa la arkay taas oo muujinaysa in MnCo2O4 aanu u shaqayn si la mid ah MnOx.Graphene GDE waxay muujisaa waxqabadka ORR ee ugu hooseeya marka loo eego baaxadda cufnaanta hadda la tijaabiyey, taasoo muujinaysa hoos u dhac degdeg ah oo waxqabadka 100 mA cm-2.Sidaa darteed, iyadoo la raacayo shuruudaha tijaabada ah ee la doortay, MnOx GDE waxaa loo doortay baaritaanno dheeraad ah oo ku saabsan nidaamka sare ee Zn-hawo.