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Inoshanda, isingadhuri uye inogara yakasimba oxygen reduction reaction (ORR) electrocatalysts inokosha zvikuru kune yechipiri Zn-air mabhatiri.Basa reORR reimwe uye yakasanganiswa simbi oxides uye kabhoni electrocatalysts yakaongororwa uchishandisa inotenderera disk electrode (RDE) zviyero, Tafel materu, uye Kutetsky-Levich zvirongwa.Yakawanikwa kuti kusanganiswa kweMnOx uye XC-72R kunoratidza basa rePBP rakakwirira uye kugadzikana kwakanaka, kusvika ku100 mA cm-2.Kuitwa kwemaelectrode eORR akasarudzwa uye iyo yaimbove yakagadziridzwa oxygen evolution reaction (OER) electrode yakazoyedzwa mune yakasarudzika-yakavakwa yechipiri zinc-air bhatiri mune matatu-electrode configuration, uye ikozvino density, electrolyte molarity, tembiricha, oxygen kuchena zvaive. akaedzwawo.Hunhu hweORR uye OERelectrodes.Pakupedzisira, kusimba kwechipiri zinc-air system yakaongororwa, ichiratidza kushanda kwesimba kwe58-61% pa 20 mA cm-2 mu 4 M NaOH + 0.3 M ZnO pa333 K kwemaawa makumi mana.
Metal-air mabhatiri ane okisijeni maelectrodes anoonekwa seanoyevedza masisitimu nekuti magetsi emagetsi emagetsi eokisijeni anogona kuwanikwa zviri nyore kubva kumhepo yakatenderedza uye haidi kuchengetedza1.Izvi zvinorerutsa dhizaini yehurongwa nekubvumira iyo okisijeni electrode kuve neinogumira kugona, nekudaro ichiwedzera kuwanda kwesimba rehurongwa.Naizvozvo, simbi-yemhepo mabhatiri anoshandisa anode zvinhu zvakaita selithium, aruminiyamu, simbi, zingi, uye magnesium abuda nekuda kwekugona kwavo kwakasarudzika.Pakati pawo, mabhatiri emhepo eZinc anonyatsokwanisa kuzadzisa kudiwa kwemusika kwemutengo, chengetedzo, uye hushamwari kwezvakatipoteredza, sezvo zinc ine akawanda anodiwa maitiro seanode zvinhu, sekugadzikana kwakanaka muaqueous electrolytes, yakakwira simba density, uye yakaderera kuenzana.zvinogona., electrochemical reversibility, yakanaka magetsi conductivity, kuwanda uye nyore kubata4,5.Parizvino, kunyange zvazvo mabhatiri emhepo ekutanga e-zinc anoshandiswa mune zvekutengeserana zvakadai sezvibatsiro zvekunzwa, zviratidzo zvechitima uye magetsi ekufambisa, mabhatiri emhepo echipiri e-zinc ane mukana wehuwandu hwemagetsi hunofananidzwa nemabhatiri e-lithium-based.Izvi zvinoita kuti zvive zvakakosha kuenderera mberi nekutsvaga pamusoro pezinc mabhatiri emhepo ekushandisa mumagetsi anotakurika, mota dzemagetsi, grid-scale simba rekuchengetedza uye kutsigira kugadzirwa kwesimba rinogoneka6,7.
Chimwe chezvinangwa zvakakosha ndechekuvandudza kushanda kweokisijeni pamhepo electrode, iyo inonzi oxygen reduction reaction (ORR) uye oxygen evolution reaction (OER), kuitira kusimudzira kushambadzira kwemabhatiri echipiri Zn-air.Kuti izvi zviitike, ma electrocatalyst anoshanda anogona kushandiswa kuwedzera chiyero chekuita uye nekudaro kuwedzera kugona.Parizvino, maokisijeni emagetsi ane bifunctional catalysts anotsanangurwa zvakanaka mumabhuku8,9,10.Kunyange zvazvo bifunctional catalysts inogona kurerutsa magadzirirwo emagetsi uye kuderedza kurasikirwa kwekutamisa kwakawanda, izvo zvinogona kubatsira kuderedza mari yekugadzira, mukuita, zvinokonzeresa zvinonyatsokodzera ORR kazhinji hazvina kukodzera OER, uye zvinopesana11.Iyi misiyano yekushanda inogona kuita kuti iyo catalyst ionekwe kune yakawanda yakawanda yezvinogona, izvo zvinogona kuchinja chimiro chayo chepamusoro nekufamba kwenguva.Pamusoro pezvo, kupindirana kwemasimba anosunga epakati zvinoreva kuti nzvimbo dzinoshanda pane inokonzeresa dzinogona kuve dzakasiyana pane yega yega kuita, izvo zvinogona kuomesa optimization.
Imwe dambudziko guru rechipiri mabhatiri eZn-air ndiko kugadzirwa kweokisijenielectrode, kunyanya nekuti iyo monofunctional catalysts yeORR neOER inoshanda mune dzakasiyana reaction media.Iyo ORR gasi diffusion layer inofanira kunge iri hydrophobic kubvumira gasi reokisijeni kupinda munzvimbo dzinokonzeresa, nepo kune OER iyo electrode yepamusoro inofanira kunge iri hydrophilic kuti iite kubviswa kweokisijeni bubbles.Pamusoro pemuonde.1 inoratidza matatu akajairwa echipiri okisijeni electrode magadzirirwo akatorwa kubva kuongororo naJorissen12, zvinoti (i) bifunctional monolayer catalysts, (ii) kaviri kana multilayer catalysts, uye (iii) katatu electrode masisitimu.
Kune yekutanga electrode dhizaini, iyo inosanganisira imwechete layer bifunctional catalyst iyo panguva imwe chete inokonzeresa ORR neOER, kana membrane inosanganisirwa mukugadzirwa uku, ipapo membrane-electrode assembly (MEA) inoumbwa sezvakaratidzwa.Rudzi rwechipiri runosanganisira maviri (kana kupfuura) mabhedha anokonzeresa ane akasiyana porosity uye hydrophobicity kuti azvidavirire kune misiyano munzvimbo dzekuita13,14,15.Mune zvimwe zviitiko, mibhedha miviri inokonzeresa inoparadzaniswa, nedivi rehydrophilic reOER rakatarisana neelectrolyte uye semi-hydrophobic side reORR rakatarisana nemigumo yakavhurika yemagetsi 16, 17, 18. sero rine maviri reaction- chaiyo okisijeni electrode uye zinc electrode19,20.Tafura S1 inonyora zvakanakira uye zvakaipira zvega yega dhizaini.
Kuitwa kwedhizaini ye electrode inoparadzanisa maitiro eORR neOER kwakamboratidza kugadzikana kwebhasikoro19.Izvi ndezvechokwadi kunyanya kune matatu electrode configuration, apo kuderedzwa kwekusagadzikana kwezvinokonzera uye co-additives kunoderedzwa uye kubuda kunze kunowedzera kudzoreka pamusoro pehuwandu hunogona kuitika.Nokuda kwezvikonzero izvi, takashandisa matatu-electrode Zn-air configuration mubasa iri.
Muchinyorwa chino, isu tinotanga tasarudza yakakwirira performance ORR catalysts nekuenzanisa akasiyana ekuchinja simbi oxides, carbonaceous zvinhu, uye mareferensi catalysts ane inotenderera disk electrode (RDE) kuyedza.Transition metal oxides inowanzova yakanaka electrocatalysts nekuda kwekusiyana kwavo oxidation states;maitiro anoitwa nyore nyore pamberi pezvisanganiswa izvi21.Semuenzaniso, manganese oxides, cobalt oxides, uye cobalt-based yakasanganiswa oxides (yakadai seNiCo2O4 uye MnCo2O4) 22,23,24 inoratidza yakanaka ORR mumamiriro ealkaline nekuda kwehafu-yakazadzwa d-orbitals, erekitironi simba mazinga anobvumira maerekitironi. kushanda uye kunatsiridza kucheka kunyaradza.Mukuwedzera, ivo vanonyanya kuwanda munharaunda uye vane magetsi anogamuchirwa conductivity, high reactivity uye kugadzikana kwakanaka.Saizvozvo, carbonaceous zvinhu zvinoshandiswa zvakanyanya, zvine zvakanakira zvemhando yepamusoro yemagetsi conductivity uye yakakura nzvimbo.Mune zvimwe zviitiko, heteroatoms yakadai senitrogen, boron, phosphorus, uye sulfuri yakaunzwa mucarbon kuti igadzirise chimiro chayo, ichiwedzera kuvandudza maitiro eORR ezvinyorwa izvi.
Zvichienderana nemhedzisiro yekuedza, takabatanidza maOVR catalysts akasarudzwa mugasi diffusion electrodes (GDE) uye tikaaedza pamhando dzakasiyana dzemazuva ano.Iyo inoshanda zvakanyanya ORR GDE catalyst yakabva yaunganidzwa mutsika yedu matatu-electrode yechipiri Zn-air bhatiri pamwe ne reaction-specific OER maelectrodes akagadziridzwa mubasa redu rapfuura26,27.Izvo zvinogoneka zvema electrode eokisijeni ega ega akatariswa panguva yekuramba ichiyerera uye kuchaja bhasikoro kuedza kuongorora mabatiro emamiriro ekushanda akadai sehuwandu hwazvino, electrolyte molarity, tembiricha yekushandisa sero, uye kuchena kweokisijeni.Pakupedzisira, kugadzikana kweZn-air mabhatiri echipiri akaongororwa pasi pekuenderera mberi kwebhasikoro pasi pemamiriro ekushanda.
MnOx28 yakagadzirwa nemakemikari redox nzira: 50 ml ye 0.04 M KMnO4 mhinduro (Fisher Sayenzi, 99%) yakawedzerwa ku100 ml ye0.03 Mn (CH3COO) 2 (Fisher Sainzi, 98%) kuti igadzire mvura yebrown.Musanganiswa unogadziriswa kuita pH 12 ne dilute sodium hydroxide, wozoiswa centrifuged 3-5 nguva pa 2500 rpm kuunganidza mvura inonaya.Mvura yaibva yagezwa nemvura yakasvibiswa kusvikira ruvara rwepepuru rweion permanganate yanyangarika.Pakupedzisira, madhipoziti akaomeswa nemhepo pa333 K husiku humwe ndokubva apwanywa.
Spinel oxides Co3O4, NiCo2O4, uye MnCo2O4 akagadzirwa nekuora kwekupisa.NiCo2O4 uye MnCo2O4 dzakagadzirwa nekuwedzera 0.5 M (14.5 g) nickel(II) nitrate hexahydrate, Ni(NO3)2⋅6H2O (Fisher Scientific, 99.9%) kana 0.5 M (12.6 g) tetrahydrate manganese(II) nitrate Mn(NO3) ))2 4H2O (Sigma Aldrich, ≥ 97%) uye 1 M (29.1 g) cobalt(II) nitrate hexahydrate, Co(NO3)2 6H2O (Fisher Scientific, 98+%, ACS reagents) mu methanol (Fisher Scientific%, 99. ) mu100 ml dilution vials.Methanol inowedzerwa muzvikamu zviduku kune shanduko yesimbi nitrate nekuenderera mberi ichikurudzira kusvikira mhinduro ine homogeneous inowanikwa.Mhinduro yacho yakabva yaendeswa kune crucible uye inopisa pandiro inopisa, ichisiya yakasviba tsvuku yakasimba.Iyo yakasimba yakaverengerwa pa648 K kwe20 h mumhepo.Iyo yakasimba yaibva yakuyiwa kuita upfu hwakatsetseka.Kwete Ni(NO3)2 6H2O kana Mn(NO3)2 4H2O yakawedzerwa panguva yekugadzirwa kweCo3O4.
Graphene nanosheets ine nzvimbo ye300 m2/g (Sigma Aldrich), graphene doped nenitrogen (Sigma Aldrich), carbon black poda (Vulcan XC-72R, Cabot Corp., 100%), MnO2 (Sigma Aldrich) uye 5 wt.% Pt/C (Acros Organics) yakashandiswa sezvairi.
RDE (Pine Research Instrumentation) zviyero zvakashandiswa kuongorora basa rezvakasiyana-siyana zveORR catalysts mu 1 M NaOH.A catalytic inki inosanganisira 1 mg catalyst + 1 ml deionized (DI) H2O + 0.5 ml isopropanol (IPA) + 5 µl 5 wt% Nafion 117 (Sigma-Aldrich) yakashandiswa sezvairi.Pakawedzerwa Vulcan XC-72R, pendi inokonzeresa yaisanganisira 0.5 mg catalyst + 0.5 mg Vulcan XC-72R + 1 ml DI HO + 0.5 ml IPA + 5 µl 5 wt% Nafion 117 kuve nechokwadi chekurodha zvinhu.Musanganiswa wakaitwa sonicated kwemaminitsi makumi maviri uye homogenized uchishandisa Cole-Parmer LabGen 7 Series homogenizer pa 28,000 rpm kwemaminitsi mana.Iyo inki yakabva yaiswa mumatatu matatu e8 μl kumusoro kwegirazi kabhoni electrode (Pine Instrument Company) ine dhayamita ye4 mm (nzvimbo yekushanda ≈ 0.126 cm2) uye yakaomeswa pakati pezvikamu kuti ipe mutoro we ≈120 μg cm. -2.Pakati pemashandisirwo, iyo girazi kabhoni kabhoni electrode pamusoro yakatevedzana yakanyorova yakakwenenzverwa neMicroCloth (Buehler) uye 1.0 mm uye 0.5 mm alumina poda (MicroPolish, Buehler) ichiteverwa ne sonication mu deionized H2O.
ORR gasi diffusion electrode samples dzakagadzirirwa maererano neyakatsanangurwa protocol28 yedu.Kutanga, iyo catalyst powder uye Vulcan XC-72R yakasanganiswa muchiyero che1: 1.Zvadaro musanganiswa wemhinduro ye polytetrafluoroethylene (PTFE) (60 wt.% muH2O) uye yakagadziriswa ine chiyero che IPA / H2O ye1: 1 yakawedzerwa kune yakaoma poda musanganiswa.Sonicate iyo catalytic pendi kwemaminitsi makumi maviri uye homogenize kwemaminitsi mana pa 28,000 rpm.Iyo inki yakazoiswa mutete ne spatula pa pre-cut carbon paper 13 mm muhupamhi (AvCarb GDS 1120) uye yakaomeswa kusvikira catalyst content ye 2 mg cm2 yasvika.
Maelectrodhi eOER akagadzirwa necathodic electrodeposition yeNi-Fe hydroxide catalysts pane 15 mm x 15 mm simbi isina tsvina.mesh(DeXmet Corp, 4SS 5-050) sezvakataurwa26,27.Electrodeposition yakaitwa muyero matatu-electrode half-cell (a polymer-coated glass cell of about 20 cm3) ine Pt grid se counter electrode uye Hg/HgO mu 1 M NaOH sereferensi electrode.Bvumira iyo catalyst yakavharwa nesimbi isina tsvina mesh kuti iome isati yacheka nzvimbo inosvika 0.8 cm2 ine 10 mm gobvu kabhoni simbi punch.
Kuenzanisa, kutengesa ORR uye OER electrodes yakashandiswa sekugamuchirwa uye kuedzwa pasi pemamiriro akafanana.Iyo yekutengeserana ORR electrode (QSI Nano Gasi Diffusion Electrode, Quantum Sphere, 0.35 mm gobvu) ine manganese uye kabhoni oxide yakavharwa ne nickel mesh ikozvino muunganidzi, ukuwo OER electrode yekutengeserana (rudzi 1.7, yakakosha Magneto anode, BV) ine ukobvu 1.3 mm.kusvika 1.6 mm yakawedzera titanium mesh yakavharwa neRu-Ir yakasanganiswa simbi oxide.
Iyo yepamusoro morphology uye kuumbwa kwezvinokonzeresa zvakaratidzwa pachishandiswa FEI Quanta 650 FEG scanning electron maikorosikopu (SEM) inoshanda pasi pepamusoro vacuum uye accelerating voltage ye5 kV.Powder X-ray diffraction (XRD) data yakaunganidzwa paBruker D8 Advance X-ray diffractometer ine copper tube source (λ = 1.5418 Å) uye yakaongororwa pachishandiswa Bruker Diffraction Suite EVA software.
Ese electrochemical kuyerwa kwakaitwa pachishandiswa Biologic SP-150 potentiostat uye EC-lab software.Samples yeRDE neGDE yakaedzwa payakajairwa matatu-electrode setup ine 200 cm3 jekete regirazi sero uye Laggin capillary sereferenzi electrode.Pt mesh uye Hg/HgO mu 1 M NaOH yakashandiswa seanopikisa uye mareferenzi emagetsi, zvichiteerana.
Pazviyero zveRDE muchiyedzo chega chega, patsva 1 M NaOH electrolyte yakashandiswa, tembiricha yacho yaichengetwa iri pa298 K uchishandisa bhati remvura rinotenderera (TC120, Grant).Gaseous oxygen (BOC) yakanga ichitubwida muelectrolyte kuburikidza negirazi frit ine porosity ye25–50 µm kweinenge 30 min isati yaedzwa yega.Kuti uwane ORR polarization curves, zvingave zvakaongororwa kubva ku0.1 kusvika -0.5 V (zvichienderana neHg / HgO) pachiyero chekuongorora che 5 mV s -1 pa 400 rpm.Cyclic voltammograms yakawanikwa nekutsvaira zvingave pakati pe0 ne -1.0 V neHg/HgO pamwero we50 mV s-1.
Pazviyero zveHDE, iyo 1 M NaOH electrolyte yakachengetedzwa pa333 K ine bhati remvura rinotenderera.Nzvimbo inoshanda ye 0.8 cm2 yakaratidzwa kune electrolyte nekuenderera mberi kweokisijeni kudivi rekumashure re electrode pamwero we200 cm3 / min.Nharaunda yakatarwa pakati pe electrode inoshanda uye referensi electrode yaiva 10 mm, uye kureba pakati pekushanda kwe electrode uye counter electrode yaiva 13-15 mm.Nickel waya uye mesh zvinopa magetsi kubata padivi pegasi.Chronopotentiometric zviyero zvakatorwa pa10, 20, 50 uye 100 mA cm-2 kuti iongorore kugadzikana uye kushanda kwe electrode.
Hunhu hweORR neOER maelectrodes akaongororwa mu200 cm3 jekete regirazi sero rine PTFE29 yekuisa.A schematic diagram ye system inoratidzwa muFigure S1.Ma electrode ari mubhatiri akabatanidzwa mune matatu-electrode system.Iyo electrode yekushanda yaisanganisira yakaparadzana reaction-specific ORR uye OER electrodes yakabatana kune relay module (Songle, SRD-05VDC-SL-C) uye microcontroller (Raspberry Pi 2014© modhi B+ V1.2) ine zinc anode.as a pair Ma electrodes nereferensi electrode Hg/HgO mu 4 M NaOH akanga ari chinhambwe che 3 mm kubva kune zinc anode.A Python script yakanyorwa kuti ishande uye idzore iyo Raspberry Pi uye Relay Module.
Sero rakagadziridzwa kuti rigare zinc foil anode (Goodfellow, 1 mm gobvu, 99.95%) uye chivharo chepolymer chakabvumira kuti ma electrode aiswe panzvimbo yakatarwa ingangoita 10 m.4 mm kure.Mapuragi erabha eNitrile akagadzirisa maelectrodes muchivharo, uye waya dzenickel (Alfa Aesar, 0.5 mm dhayamita, annealed, 99.5% Ni) dzakashandiswa pamagetsi emagetsi emagetsi.Iyo zinc foil anode yakatanga kucheneswa neisopropanol uyezve nemvura yakasvibiswa, uye pamusoro pefoiri yakafukidzwa ne polypropylene tepi (Avon, AVN9811060K, 25 µm gobvu) kuratidza nzvimbo inoshanda inosvika 0.8 cm2.
Zvese zvekuzama bhasikoro zvakaitwa mu4 M NaOH + 0.3 M ZnO electrolyte pa333 K kunze kwekunge zvaonekwa.Mumufananidzo, Ewe maererano neHg/HgO inoreva kugona kweokisijeni electrode (ORR uye OER), Ece maererano neHg/HgO inomiririra kugona kwezinc electrode, Ecell maererano neHg/HgO inomiririra yakazara. sero kugona kana mutsauko ungangoita.pakati pemabhatiri maviri anokwanisa.Oxygen kana mhepo yakamanikidzwa yaipiwa kudivi rekuseri kweOPP electrode panguva yekuyerera kwe 200 cm3 / min.Kugadzikana kwebhasikoro uye kushanda kwema electrode kwakadzidzwa pahuwandu huripo hwe 20 mA cm-2, nguva yekutenderera ye30 min, uye nguva yekuzorora yeOCV ye1 min pakati pehafu yega yega.Zvishoma zvezvikamu gumi zvakaitwa pamuedzo wega wega, uye data yakatorwa kubva mumitambo 1, 5, uye 10 kuti ione mamiriro emagetsi ekufamba kwenguva.
Iyo morphology yeORR catalyst yakaratidzwa neSEM (Fig. 2), uye powder X-ray diffraction zviyero zvakasimbisa kristall structure yemasampuli (Fig. 3).Izvo zvigadziro zvezvigadziriso zvecatalyst samples zvinopihwa muTebhurari 1. 1. Pakufananidza manganese oxides, kutengeserana MnO2 mufig.2a ine zvikamu zvakakura, uye maitiro ekuparadzanisa muFig. 3a inoenderana neJCPDS 24-0735 ye tetragonal β-MnO2.Pane zvinopesana, pamusoro peMnOx pamusoro peFig. 2b inoratidza zvinyoro zvishoma uye zvinyoro zvishoma, izvo zvinopindirana nediffraction pattern muFig. 66 ° inoenderana nepamusoro (110), (220), (310), (211), uye (541) ye tetrahedally yakanangidzirwa α-MnO2 hydrate, JCPDS 44-014028.
(a) MnO2, (b) MnOx, (c) Co3O4, (d) NiCo2O4, (e) MnCo2O4, (f) Vulcan XC-72R, (g) graphene, (h) nitrogen doped graphene, (uye) 5 wt .% Pt/C.
X-ray maitiro e(a) MnO2, (b) MnOx, (c) Co3O4, (d) NiCo2O4, (e) MnCo2O4, (f) Vulcan XC-72R, nitrogen-doped graphene uye graphene, uye (g) 5 % platinum/carbon.
Pamusoro pemuonde.2c–e, the surface morphology of oxides yakavakirwa pacobalt Co3O4, NiCo2O4, uye MnCo2O4 ine masumbu ezvimedu zvisingaenzaniswi.Pamusoro pemuonde.3c-e inoratidza kuti zvese izvi shandukosimbioxides ine spinel chimiro uye yakafanana cubic crystal system (JCPDS 01-1152, JCPDS 20-0781, uye JCPDS 23-1237, zvichiteerana).Izvi zvinoratidza kuti nzira yekupisa yekupisa inokwanisa kubudisa yakanyanya crystalline metal oxides, sezvinoratidzwa nepamusoro-soro yakanyatsotsanangurwa mumhando ye diffraction.
SEM mifananidzo yezvinhu zvekabhoni inoratidza shanduko huru.Pamusoro pemuonde.2f Vulcan XC-72R kabhoni nhema ine nanoparticles yakazara yakazara.Pane zvinopesana, kutaridzika kwegraphene muFig. 2g mahwendefa akavhiringidzika zvikuru ane mamwe agglomerations.Zvisinei, N-doped graphene (Fig. 2h) inoratidzika kunge ine zvidimbu zvitete.Iyo inoenderana X-ray diffraction mapatani eVulcan XC-72R, yekutengesa graphene nanosheets, uye N-doped graphene muFig.3f inoratidza shanduko diki mu2θ tsika dze (002) uye (100) carbon peaks.Vulcan XC-72R inozivikanwa sehexagonal graphite muJCPDS 41-1487 ine peaks (002) uye (100) inoonekwa pa24.5 ° uye 43.2 ° zvakateerana.Saizvozvo, iyo (002) uye (100) yepamusoro yeN-doped graphene inoonekwa pa26.7 ° uye 43.3 °, zvichiteerana.Kusimba kwemashure kunocherechedzwa muX-ray diffraction mapatani eVulcan XC-72R uye nitrogen-doped graphene imhaka yekusarongeka kwakanyanya kwezvinhu izvi muchimiro chazvo chepamusoro.Kusiyana neizvi, iyo diffraction pattern ye graphene nanosheets inoratidza yakapinza, yakanyanyisa peak (002) pa 26.5 ° uye duku yakafara peak (100) pa 44 °, ichiratidza imwe crystalline chimiro chemuenzaniso uyu.
Pakupedzisira, mufig.2i SEM mufananidzo we5 wt.% Pt / C inoratidza tsvimbo-yakaita kabhoni zvimedu zvine denderedzwa voids.Cubic Pt inotarirwa kubva kune dzakawanda dzepamusoro mu5 wt% Pt / C diffraction pattern muFig. 3g, uye iyo yepamusoro pa23 ° inoenderana ne (002) yepamusoro yekabhoni iripo.
Mutsara wekutsvaira ORR catalyst voltammogram yakanyorwa pamwero wekutsvaira we5 mV s-1.Nekuda kwekuganhurirwa kwekutamisa vanhu vakawanda, mamepu akaunganidzwa (Fig. 4a) anowanzova neS-shape inotambanukira kune bani rine mikana yakawanda yakaipa.Iyo inogumira ikozvino density, jL, inogona E1 / 2 (apo j/jL = ½) uye yekutanga kugona pa -0.1 mA cm-2 yakatorwa kubva muzvirongwa izvi uye yakanyorwa muTebhu 2. Zvakakosha kuziva kuti mufig.4a, macatalysts anogona kukamurwa maererano nezvaanogona E1/2 kuita: (I) metal oxides, (II) carbonaceous materials, uye (III) noble metals.
Linear sweep voltammograms ye (a) catalyst uye (b) firimu rakatetepa recatalyst uye XC-72R, yakayerwa paRDE glassy carbon probe pa400 rpm ine scan rate ye5 mV s-1 muO2 saturation pa298 K mu1. M NaOH cf.
Individual metal oxides yeMn uye Co muboka I kuratidza yekutanga kugona kwe -0.17 V uye -0.19 V zvakateerana, uye E1/2 kukosha dziri pakati -0.24 uye -0.26 V. Kuderedzwa kwekuita kweaya oxides esimbi kunoratidzwa muequation. .(1) uye (2), iyo inoonekwa padivi pekutanga kugona muFig.4a inoenderana neyakajairwa danho rekutanga nhanho 2e yeORR isina kunanga nzira muequation.(3).
Iyo yakasanganiswa simbi oxides MnCo2O4 uye NiCo2O4 muboka rimwe chete inotaridza yakagadziridzwa zvishoma yekutanga kugona pa -0.10 uye -0.12 V zvakateerana, asi chengetedza E1/2 kukosha kweanosvika gumi.−0.23 volts.
Boka II kabhoni zvinhu zvinoratidza zvakawanda zvakanaka E1/2 kukosha pane boka I simbi oxides.Graphene zvinhu zvine mukana wekutanga we -0.07 V uye E1/2 kukosha kwe -0.11 V, nepo yekutanga kugona uye E1/2 ye72R Vulcan XC- ari -0.12V uye -0.17V zvichiteerana.Muboka rechitatu, 5 wt% Pt / C yakaratidza iyo yakanyanya kunaka yekutanga kugona pa 0.02 V, E1 / 2 ye -0.055 V, uye muganhu wepamusoro pa -0.4 V, sezvo kuderedzwa kweokisijeni kwakaitika kuburikidza nehuwandu hwemazuva ano hwe 4e nzira. .Iyo ine zvakare yakaderera E1 / 2 nekuda kweiyo yepamusoro conductivity yePt / C uye inodzoreredzwa kinetics yeORR reaction.
Mufananidzo S2a inopa Tafel slope yekuongorora kune akasiyana catalysts.Kinetically controlled region ye5 wt.% Pt/C inotanga pa 0.02 V maererano neHg/HgO, ukuwo dunhu resimbi okisidhisi uye kabhoni zvinhu zviri muchikamu chezvakashata zvinogona kubva -0.03 kusvika -0.1 V. The slope value yeTafel Pt/C ndeye -63.5 mV ss–1, iyo inofananidzwa nePt panguva yakaderera densities dE/d log i = -2.3 RT/F31.32 umo nhanho-yekugadzirisa nhanho inosanganisira kuchinja kweokisijeni kubva ku physisorption chemisorption33,34.Iyo Tafel yakatsetseka tsika dzekabhoni zvinhu zviri mudunhu rimwechete nePt/C (-60 kusvika -70 mV div-1), zvichiratidza kuti zvinhu izvi zvine nzira dzakafanana dzeORR.Individual metal oxides yeCo uye Mn inoshuma Tafel materu kubva -110 kusvika -120 mV dec-1, inova dE / d log i = -2.3 2RT / F, apo chiyero chekutsvaga nhanho ndiyo yekutanga erekitironi.kutamisa nhanho 35, 36. Yakakwira zvishoma pamateru tsika dzakarekodhwa kune yakasanganiswa simbi okisi NiCo2O4 uye MnCo2O4, ingangoita -170 mV dec-1, inoratidza kuvepo kweOH- uye H2O ion pamusoro peiyo oxide, iyo inodzivirira kunyura kweokisijeni uye. electron transfer, nokudaro inokanganisa oxygen.kuderedza nzira 35.
Iyo Kutetsky-Levich (KL) equation yakashandiswa kuona iyo kinetic reaction paramita kune akasiyana siyana catalyst samples pasina kuwanda kutamiswa.mu equation.(4) hwerengedzo yakayerwa ikozvino density j ihuwandu hwehuwandu hwazvino hwekutamisa maerekitironi uye kutamiswa kwehuwandu.
kubva ku equation.(5) Iyo inodzikamisa yazvino density jL inoenderana neskweya mudzi wekutenderera kwekutenderera.Naizvozvo, iyo KL equation.(6) inotsanangura mutsara wegirafu we j-1 maringe ne ω−1//2, apo mharadzano iri jk uye kutenuka kwegirafu ndi K.
apo ν ndiyo kinematic viscosity ye electrolyte 1 M NaOH (1.1 × 10–2 cm2 s–1)37, D ndiyo diffusion coefficient ye O2 mu 1 M NaOH (1.89 × 10–5 cm2 s–1)38, ω is rpm is the rotation speed, C is the oxygen concentration in the bulk solution (8.4 × 10-7 mol cm-3)38.
Unganidza mutsara wakatsvaira voltammograms uchishandisa RDE pa100, 400, 900, 1600, uye 2500 rpm.Values ​​​​yakatorwa kubva -0.4 V munharaunda shoma yekutamisa ruzhinji kuronga dhizaini yeKL, kureva -j-1 maringe ne ω-1//2 yecatalyst (Fig. S3a).Shandisa equations.Mune equation (6) uye (7), zviratidzo zvekushanda zvechikonzereso, senge kinetic ikozvino density pasina kufunga nezve mhedzisiro yekutamisa huwandu jk, inotarirwa nenzvimbo yekuyambuka ne y axis, uye nhamba ye erekitironi kutamiswa kunotemerwa ne gradient K ye curve.Ivo vakanyorwa mutafura 2.
5 wt% Pt/C uye XC-72R vane yakaderera absolute jk kukosha, zvichiratidza kukurumidza kinetics yezvinhu izvi.Zvisineyi, kutenuka kwe XC-72R curve kunosvika zvakapetwa kaviri pa5 wt% Pt/C, zvinotarisirwa sezvo K iri chiratidzo chehuwandu hwemaerekitironi anotamiswa panguva yekutapudza oxygen.Nechepfungwa, chirongwa cheKL che5 wt% Pt/C chinofanirwa kupfuura nepakati peiyo 39 mabviro pasi pemamiriro ekutamisa mashoma, zvisinei izvi hazvionekwe muMufananidzo S3a, zvichiratidza kugumira kwekinetic kana diffusional inokanganisa mhedzisiro.Izvi zvinogona kunge zviri nekuti Garsani et al.40 yakaratidza kuti kusawirirana kuduku mu topology uye morphology yePt / C catalytic films inogona kukanganisa kurongeka kweORR maitiro emabasa.Nekudaro, sezvo ese mafirimu anokonzeresa akagadzirwa nenzira imwechete, chero mhedzisiro pamhedzisiro inofanirwa kunge yakafanana kune ese masampuli.Iyo graphene KL cross point ye ≈ -0.13 mA-1 cm2 inofananidzwa neye XC-72R, asi iyo -0.20 mA-1 cm2 cross point yeN-doped graphene KL graph inoratidza kuti density iripo yakakura zvinoenderana iyo voltage pane catalytic converter.Izvi zvinogona kunge zvichikonzerwa nekuti nitrogen doping yegraphene inoderedza kutenderera kwemagetsi kwese, zvichikonzera kunonoka kufambiswa kwemagetsi kinetics.Kusiyana neizvi, iyo yakakwana K kukosha kwenitrogen-doped graphene idiki pane yegraphene nekuti kuvepo kwenitrogen kunobatsira kugadzira nzvimbo dzinoshanda dzeORR41,42.
Kune maokisi akavakirwa pane manganese, iyo mharadzano poindi yehukuru hwakanyanya kukosha inoonekwa - 0.57 mA-1 cm2.Zvakadaro, iyo yakakwana K kukosha kweMnOx yakaderera zvakanyanya pane iyo yeMnO2 uye iri padyo ne5 wt%.%Pt/C.Nhamba dzekutumira maelectron dzakatemerwa kuva approx.MnOx ndeye 4 uye MnO2 iri pedyo ne2. Izvi zvinopindirana nemigumisiro yakabudiswa mumabhuku, iyo inoshuma kuti nhamba ye electron transfers mu α-MnO2 ORR nzira ndeye 4, nepo β-MnO243 inowanzova pasi pe4. Nokudaro Nokudaro , nzira dzeORR dzinosiyana kune dzakasiyana-siyana dzepolymorphic mafomu ezvigadziriswe zvichienderana nemanganese oxide, kunyange zvazvo mazinga emakemikari matanho anoramba akafanana.Kunyanya, maMnOx neMnCo2O4 catalysts ane nhamba dzekufambisa maerekitironi zvishoma kudarika 4 nokuti kuderedza manganese oxides aripo mune izvi zvinokonzera kunoitika panguva imwe chete nekuderedzwa kweokisijeni.Mune rimwe basa rakapfuura, takaona kuti kuderedzwa kwe electrochemical ye manganese oxide kunoitika munzvimbo imwechete inogona kuderedzwa sekuderedzwa kweokisijeni mumushonga wakazadzwa nenitrogen28.Kubatsira kwemaitiro emativi kunotungamirira kunhamba yakaverengwa yemaerekitironi zvishoma kudarika 4.
Mharadzano yeCo3O4 ndeye ≈ −0.48 mA-1 cm2, iyo isina kunaka zvishoma pane maviri manganese oxide, uye inooneka electron transfer number inotarwa nekukosha kweK yakaenzana ne2. Kutsiva Ni muNiCo2O4 uye Mn muMnCo2O4 neCo inotungamirira kuderera kwehutano hwakakwana K, iyo inoratidza kuvandudzwa kwekinetics yekutamisa maerekitironi mumisanganiswa yesimbi oxides.
Carbon substrates inowedzerwa kuORR catalyst inki kuti iwedzere kufambiswa kwemagetsi uye kufambisa kwakakodzera-nhatu-chikamu muganhu kuumbwa mune gasi diffusion electrodes.Vulcan-XC-72R yakasarudzwa nekuda kwemutengo wayo wakaderera, nzvimbo yakakura ye250 m2 · g-1, uye yakaderera resistivity ye0.08 kusvika 1 Ω · cm44.45.Chirongwa cheLSV chemuenzaniso we catalyst wakasanganiswa neVulcan XC-72R pa400 rpm inoratidzwa mumufananidzo 1. 4b.Mhedzisiro yakanyatsojeka yekuwedzera iyo Vulcan XC-72R ndeyekuwedzera iyo yekupedzisira density iripo.Ziva kuti izvi zvinonyanya kuoneka kune simbi oxides, pamwe nekuwedzera 0.60 mA cm-2 kune imwechete simbi oxides, 0.40 mA cm-2 kune yakasanganiswa metal oxides, uye 0.28 mA cm-2 yegraphene uye doped graphene.N. Wedzera 0.05 mA cm-2.−2.Kuwedzerwa kweVulcan XC-72R kune inki inogadzirisa yakakonzerawo kuchinja kwakanaka mukukwanisa kwekutanga uye E1 / 2 hafu-wave inogona kune zvose zvinokonzera kunze kwegraphene.Shanduko idzi dzinogona kunge dziri mhedzisiro yekuwedzera kushandiswa kwe electrochemical pamusoro penzvimbo46 uye yakagadziridzwa yekubata47 pakati pezvinokonzeresa zvimedu pane inotsigirwa Vulcan XC-72R catalyst.
Iyo inoenderana Tafel zvirongwa uye kinetic paramita yeiyi catalyst musanganiswa inoratidzwa muMufananidzo S2b uye Tafura 3, zvichiteerana.Iwo Tafel materu maitiro aive akafanana neMnOx uye graphene zvinhu zvine uye pasina XC-72R, zvichiratidza kuti nzira dzavo dzeORR hadzina kukanganiswa.Nekudaro, iyo cobalt-based oxides Co3O4, NiCo2O4 uye MnCo2O4 yakapa madiki asina kunaka eTafel materu pakati -68 uye -80 mV dec-1 pamwe neXC-72R inoratidza shanduko munzira yeORR.Mufananidzo S3b inoratidza chirongwa cheKL chemuenzaniso wecatalyst wakasanganiswa neVulcan XC-72R.Kazhinji, kuderera kweiyo mhedziso kukosha kwejk kwakacherechedzwa kune ese macatalysts akasanganiswa neXC-72R.MnOx yakaratidza kuderera kukuru mukukosha kwakakwana kwejk ne55 mA-1 cm2, nepo NiCo2O4 yakanyora kuderera ne 32 mA-1 cm-2, uye graphene yakaratidza kuderera kuduku ne5 mA-1 cm2.Zvinogona kugumiswa kuti mhedzisiro yeVulcan XC-72R pakuita kweiyo catalyst inogumira nebasa rekutanga recatalyst maererano neOVR.
Vulcan XC-72R haikanganisi maK maitiro eNiCo2O4, MnCo2O4, graphene, uye nitrogen-doped graphene.Zvisinei, kukosha kweK kweCo3O4 kwakaderera zvakanyanya nekuwedzera kweVulcan XC-72R, zvichiratidza kuwedzera kwehuwandu hwemagetsi anotamiswa neORR.Kubatana kwakadaro kweCo3O4 nekabhoni zvikamu kwave kutaurwa mune refs.48, 49. Mukusavapo kwekabhoni kutsigirwa, Co3O4 inofungidzirwa kuti inokurudzira kusaenzana kweHO2- kuO2 uye OH-50.51, iyo inobvumirana zvakanaka neCo3O4's electron transfer number inenge 2 muTafura 2. Nokudaro, iyo adsorption yemuviri yeCo3O4 pane kabhoni substrates inotarisirwa kuburitsa 2 + 2 mana-electron ORR nzira52 iyo yekutanga electroreducer O2 kuenda ku HO2- pakusangana kweCo3O4 catalyst uye Vulcan XC-72R (equation 1) uyezve HO2 - Iyo inokurumidza kuparadzaniswa. simbi oxide pamusoro inoshandurwa kuita O2 inoteverwa ne electroreduction.
Kusiyana neizvi, kukosha kwakakwana kweK MnOx kwakawedzera nekuwedzera kweVulcan XC-72R, iyo inomiririra kuderera kwenhamba yekufambisa maerekitironi kubva pa4.6 kusvika ku3.3 (Table 3).Izvi zvinokonzerwa nekuvapo kwemasaiti maviri pane kabhoni catalyst composite yematanho maviri erekitironi nzira.Kudzikiswa kwekutanga kweO2 kuenda kuHO2- kunoitika nyore nyore pamatsigiro ekabhoni, zvichikonzera kuwedzera kushoma kwekuda kwema-electron nzira yeORR53.
Kugadzikana kweiyo catalyst kwakaongororwa muGDE hafu-sero muhuwandu hwehuwandu hwemazuva ano.Pamusoro pemuonde.5 inoratidza zvirongwa zvinogoneka maringe nenguva yeGDE MnOx, MnCo2O4, NiCo2O4, graphene, uye nitrogen-doped graphene.MnOx inoratidza kunaka kwese kugadzikana uye kuita kweORR pane yakaderera uye yakakwira ikozvino densities, zvichiratidza kuti yakakodzera kune imwe optimization.
Chronopotentiometry yeHDE samples panguva ino kubva pa10 kusvika ku100 mA/cm2 mu1 M NaOH, 333 K, O2 inoyerera 200 cm3/min.
MnCo2O4 inoratidzika kunge iine kugadzikana kwakanaka kweORR pane yazvino density range, asi pakakwirira ikozvino density ye50 uye 100 mA cm-2 yakakura overvoltage inocherechedzwa ichiratidza kuti MnCo2O4 haishande seMnOx.Graphene GDE inoratidza yakaderera ORR performance pamusoro peiyo density range yakaedzwa, ichiratidza kudonha nekukurumidza mukuita pa100 mA cm-2.Naizvozvo, pasi pemamiriro ekuyedza akasarudzwa, MnOx GDE yakasarudzwa kuti iwedzere bvunzo muZn-air yechipiri system.