Hlau Oxide Electrode Failure Mechanism

Ua tsis tiav mechanism ntawm hlau oxide electrode

Lub attenuation ntawm hlau oxide electrode kev ua si tshwm sim nyob rau hauv lub active txheej/electrolyte interface thiab lub substrate/active interface. Nrog rau kev nce qib ntawm electrolysis, lub anode txheej maj mam poob tawm, thiab covtitaniumsubstrate yog passivated nyob rau hauv tej qhov chaw tsis muaj zog. Cov kev ua haujlwm catalytic ntawm cov electrode maj mam tsis muaj zog kom txog thaum nws poob nws cov dej num tag, raws li pom hauv daim duab 1.3

a- Ua ntej electrolysis; b-Electrolysis; c-Tom qab inactivation; 1-Titanium substrate;2-Cov txheej txheem nquag;3-TiO2

Fig.1.3 Sketch daim ntawv qhia ntawm hlau oxide anode thaum lub sij hawm intensifying lub neej

Ntau tus kws tshawb fawb tau kawm txog qhov ua rau electrode tsis ua haujlwm. Tam sim no, cov kws tshawb fawb hauv tsev thiab txawv teb chaws muaj qhov tsis sib haum xeeb ntawm qhov no, feem ntau raws li hauv qab no:

(1) Dissolution ntawm Ru02:

Hauv ruthenium txheej, Ru02 yog lub ntsiab electrocatalytic tivthaiv. Raws li kev ntsuas ntsuas kub, Ru0₂yuav oxidized rau Ru04 thaum lub peev xwm anode zoo ntawm 1.387V (vs. SHE lossis 1.146V vs. SCE):

Ru0₂+2H₂{{0}}Ru0₄+4H⁺+4e (1．20)

Ru04 tsim los ntawm cov tshuaj tiv thaiv tuaj yeem muaj nyob rau hauv daim ntawv ntawm H₂Ru0₂hauv kev daws teeb meem, thiab Ru0₄ yog ntxiv decomposed:

Ru0₄+ xH₂{{0}}Ru0_2xH₂0+0₂ (1．21)

Nyob rau hauv txoj kev no, lub electrocatalytic tivthaiv Ru02 nyob rau hauv lub txheej yuav tawm ntawm electrode thiab yaj mus rau hauv cov tshuaj, ua rau lub electrode poob nws active zog.

Raws li cov yam ntxwv ntawm txheej txheej uas tsis tiv taus acid corrosion thiab electrochemical corrosion, passivation mechanism ntawm ruthenium-titanium hlau oxide electrode yog npaj rau tsim cov void txheej. Ntawm 40 degree, O. Hauv 5mol / LH₂S0₄kev daws teeb meem, kev sim ua lub neej zoo dua qub tau ua. Cov tshuaj tua kab mob ntawm Ti0₂nyob rau hauv sulfuric acid thiab electrochemical dissolution ntawm Ru0₂ua ke los ua kom tsim cov void txheej.

Tianjin University hauv Suav teb tau kawm txog kev txhim kho corrosion ntawm Ru0₂-Ti0₂electrodes thiab taw qhia tias electrochemical dissolution ntawm active Ru Cheebtsam nyob rau hauv lub txheej yog lub ntsiab yog vim li cas rau electrode tsis ua hauj lwm. Zhang Zhaoxian tau taw qhia txog ob qhov xwm txheej ntawm anode txheej dissolution: ib qho yog qhov sib txawv ntawm tag nrho cov anode nto, thiab lwm qhov yog qhov tawg hauv ib cheeb tsam ntawm lub anode (feem ntau ntawm ntug ntawm anode). Thaum nws yaj mus rau ib qho twg thiab cov txheej txheej seem tshuav nyiaj li cas rau 18% ntawm tag nrho cov electrode nto, cov electrode yog passivated.

(2) Kev poob ntawm Ru02 catalytic kev ua si

Lub ruthenium titanium txheej yog ua los ntawm non-stoichiometric Ru0_2-x. Thiab Ti0_2-x. x yog tsim los ntawm cov tsis muaj oxygen oxides, qhov twg x yog kwv yees li ntawm 0 01 txog 0.02. Qhov chaw tiag tiag ntawm kev ua kom cov tshuaj chlorine tawm yog qhov tsis-quantitative Ru0₂. Cov oxides ntau dua, cov chaw ua haujlwm ntau dua, thiab qhov zoo dua qhov kev ua haujlwm catalytic ntawm electrode. Xibfwb DeNora ib zaug tau taw qhia: Lub conductivity ntawm coated anode yog qhov kev ua tau zoo ntawm cov distorted n-hom mix crystal generated los ntawm tib lub crystal Ru0₂+Ti0₂tom qab kev kho cua sov, uas muaj qee qhov oxygen qhov. Tab sis thaum cov pa oxygen no tau ntim nrog cov pa, cov txheej poob nws cov haujlwm electrocatalytic, thiab cov overpotential nce sai, ua rau passivation ntawm electrode. Nws ib zaug kho cov passivated anode nyob rau hauv ib qho inert roj los yog lub tshuab nqus tsev, thiab pom tias thaum lub absorbed thiab adsorbed oxygen raug tshem tawm, lub anode rov qab mus rau nws thawj tsis-electrochemical ntsuas lub xeev, reviving lub anode kev ua si.

Lub Ru0₂coated electrode tau kawm los ntawm txoj kev sim lub neej ceev ceev. Nws ntseeg tau tias kev puas tsuaj mechanism ntawm Ru0₂yog vim kev hloov pauv ntawm Ru0₂rau lwm hom oxides.

(3) Oxidation ntawm titanium substrate

Thaum lub sij hawm electrolysis, active oxygen yog generated ntawm lub anode. Tsuas yog ib feem ntawm nws tawm ntawm lub active txheej / electrode interface thiab tawm ntawm electrode nto nyob rau hauv daim ntawv ntawm oxygen thiab nkag mus rau hauv cov tshuaj, lwm ib feem ntawm cov nquag oxygen yog adsorbed rau ntawm electrode nto los ntawm diffusion los yog tsiv teb tsaws. Dhau los ntawm cov txheej txheem nquag mus txog qhov sib cuam tshuam ntawm txheej txheej thiab substrate. Cov oxides nquag no yog adsorbed rau ntawm qhov chaw ntawm lub substrate thiab tsim kev thim rov qab ntawm PN hlws ris nrog titanium. Tsis tas li ntawd, tortoise crack morphology yog ib qho qauv ntawm cov hlau oxide electrodes. Lub hav zoov ntawm cov kab nrib pleb ua rau cov electrolyte tiv tauj lub substrate los ntawm cov kab nrib pleb, ua rau oxidation ntawm lub substrate, ua rau lub active txheej nto ntog, ua rau ib tug nce nyob rau hauv lub anode muaj peev xwm, thiab qhov nce nyob rau hauv lub peev xwm ntxiv txhawb lub dissolution ntawm txheej. thiab oxidation ntawm lub substrate.

Siv cov duab scanning electron microscope ntawm electrode tsis ua hauj lwm, cov ntaub ntawv sib txawv ntawm tev txheej tuaj yeem pom):

1) Crushed peeling: cov kab nrib pleb yog ib feem tev tawm, thiab cov kab nrib pleb loj yog tawg thiab tev tawm, thiab tus neeg tev pits yog tob li substrate.

2) Convex-shaped txheej peeling: Tsuas yog ob peb txheej los ntawm qhov chaw thiab sab hauv yog tev tawm nyob rau hauv lub plab convex zoo li txheej, cov npoo ntawm qhov sib txawv tsis sib xws li cov phab ntsa tawg, thiab cov qauv moiré ib puag ncig yog pom meej.

3) Cracking spalling: ib tug xov tooj ntawm vide moire qauv nkag mus rau hauv ib tug ntev tawg nyob rau hauv qab ntawm lub tawg. Cov kab sib sib zog nqus thiab cov kab sib sib zog nqus pom pom, uas thaum kawg ua rau cov txheej txheem tsis ua haujlwm vim qhov loj flaking 4). Kev tsom xam qhia tau hais tias kev tev ntawm titanium anode txheej yog tshwm sim los ntawm kev sib xyaw ua ke ntawm cov tshuaj lom neeg thiab lub cev rog, thiab cov kev txhim kho zoo sib xws yog npaj rau ntau hom tev. Nyob rau hauv cov ntaub ntawv ntawm crushing thiab txheej tev, kev sib xyaw ntawm cov coatings thiab substrate yuav tsum tau nce; nyob rau hauv daim ntawv ntawm tawg ua tiav tev, ntxiv rau cov kev txhim kho saum toj no, tus naj npawb ntawm cov kab nrib pleb ntawm qhov qub tawg yuav tsum tau tswj.

SEM duab ntawm electrode tom qab intensifying

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