Toyota Central Research Laboratory: Solvendo compositionem gravissime afficit aggregate structuram in catalyst slurry

Solvendo compositionem de catalyst slurry significantly afficit in pore structuram de catalyst iacuit et eius scale productio efficientiam. Et pie structuram de catalyst layer est affectus multis factoribus, ut materiales proprietatibus et processus parametri. Et Ionomer ADSORPTIONption Ratio est pelagus elementum quod dominatur in aggregate structuram in slurry. Hoc articulum ad investigationem scriptor investigationis ad Toyota Central Rheological S solvendo compositionem in proprietatibus, Ionomer adsorption rate et structural characteristics aggregata in Catalyst slurry.

01

Technica background

Et catalyst iacuitAutomotive cibus cellulisSustiluit Catalyst de carbonis, et Ionomers quod transferatur protons. In industria conversionem efficientiam de cibus cellam penitus affectus raro structuram de catalyst iacuit. In Pororo Electrode, electrons sunt conducted in PT / C catalyst, protons deducuntur in Ionomer et oxygeni moleculis diffundere et penetrare in poris et ionamers. Tres substantiae generare aquam per orricorum reactionem superficiem PT Catalyst. Ut maximize in industria conversionem efficientiam de cibus cellula, necesse est ut moderari in situ et structuram de PT / C particulas et Ionomers ad optimize tres-tempus interface.

In magna-scale productio, ex princeps productio efficientiam, in catalyst accumsan solet iactaret per slit coating processus. Et slit coating modum est summus praecisione coating modum. Et coating slurry premitur a repono fabrica ad COLLUM per copia Pipeline, et slurry est sprayed a COLLUM transferre ad tunicas subiecta. In slit coating modum, in catalyst slurry composito ex PT / C particulas, ionomer et aqua-alcohol solvente premitur a repono fabrica ad COLLUM per Supple Pipeline, et slurry est in sprayed a copulatione transferre ad coated subiuga. Post siccatio in catalyst slurry, et rara catalyst accumsan transfertur ad protón commutationem membranam per calidum urgeat (ut translationem modum ad catalyst catalyst in Toyota scriptor secundus generationi fuel cella). Et structuram de catalyst iacuit paratus a superius processus est affectus multis factoribus, comprehendo materiam proprietatibus, ut genus et dispersionem statum ipsum carrier, platinum et Ionomer; Processus parametri in catalyst slurry praeparatio processus, ut solvendo compositionem, I / C Ratio, temperatus et dispersio modum. Inter eos, solvendo compositionem significantly afficit ad perficientur de catalyst iacuit.

Existente studiis revelaverunt esse rigidum aggregata in catalyst iacuit, cum magnitudine range of 100-300 NM, maxime composito ex PT / C catalyst particulas de 20-40 NM in magnitudine. Fretus in contentus et compositionem ex Ionomer, haec aggregata ulterius agglomerate ad formam aggregates 1-10 μm in magnitudine. In order to better understand the effect of solvent composition on performance, it is necessary to clarify how the solvent composition affects the structure of Pt/C particle aggregates (aggregates form the main framework of the catalyst layer) in the catalyst slurry. Hoc articulum in studio ad modum solvent compositionem super structuram habet de aggregata in catalyst slurry conducted per Toyota centralis investigationis laboratorium.

02

Praeparatio

Et solvendo compositionem in studiis est ethanol, I-propanol, et diacetone alcohol. Solvendo polarity potest regi super magna range per tres solvendo compositiones et solvente verticitatem propria hansen solubility. Sicut polarityn augetur, solutionem solvendo repellit pelagus torquem aqua onerariam in Ionomer, unde in Adsorption in Ionomer in carbo superficies et Ionomer adsorption in PT / C catalyst ad totalis Ionomer) crescit.

03

Analysis

In his figure I ostendit curvas stabilis-re publica fluxus viscosity η de catalyst slurry cum tondendas rate, in repono modulus et damnum modulus cum iactabantur, et omnes notitia puncta sunt CODOMER, in ADSORPTION RATIO γ of Ionomer in ADSORPTION RATIO Γ de Ionomer in ADSORPTIONPPTION RATIO γ ofomer, in ADSORPTION RATIO Γ of Lonomer in ADSORPTION RATIO Γ de Ionomer in ADSORPTIONPTION RATIO Γ de Ionomer in ADSORPTIONPPTION RATIO γ CODOMER in Slurrion Ratio γ-CODOMER in Slurrion. Studiis ostensum est quod tondendas extenuantibus observatum est in fere omnibus catalyst slurries, significans quod aggregata formatae in catalyst slurry sunt tondebis-destrui. Ut ostensum est in Figura III infra, ut Ionomer ADSORPTIONGPTIONPTIONGPTIONPTIONGIUM Ratio γ crescit a 0 ad XX%, omnes proprietatem valores diminutio, significans quod cum Ionomer adsorption Ratio γ crescit ad XX%, in PT / CTGRIGATA PRETIUM.

Figura I (a) Viscosity vs. Shear rate, (b) repono modulum vs. iactabantur, (c) damnum modulum vs. iactabantur. Quod color de notitia puncta indicat ad Ionomer adsorption Ratio γ (videatur in color bar ad fundum formam)

Fractal dimensionem est mensura in irregularitate complexu figuris, fere vndique a 0 ad III, cum 0 representing dispersit particulas, I representing virga, sicut aggrediuntur, II representing plana aut ramis networks, et III representing densi aggregata. Eventus ostendere quod Ionomer adsorption Ratio γ augetur, agglomeratos separatam in minoribus aggregat et in indomposable aggregata ponere structuram. Diameter aggregatorum est de CC NM. In prima viscoelastic transitus punctum ad ionomer adsorption Ratio γ ~ 0%, fractal dimensionem D2 guttae acriter a II ad I. XV% per secundam mutationes a I ad 0.5. In consistency et declinatio punctum fractal dimensionem et rhematicis proprietatibus indicat quod mutatio in rheologica proprietatibus attribuitur ad mutationem in aggregate structuram.

Secundum rheologiam proprietatibus et structurarum notatur supra, Toyota Central Research Institute propositus est corrumpuntur mechanism aggregata in catalyst slurry. Nam commodum, duo structural transitionum ad γ ~ 0% et ~ 15wt% dicuntur T1 et T2, respective. Cum Ionomer adsorption Ratio γ est inferior quam prima transitus punctum γ ~ 0%, fractal dimensionem D2 est prope II, significans formationem a colloidal gel network structuram. In hac re publica, ex ad adsorption de parva moles Ionomer in PT / aggregata, in electrostatic inter particulas parva, ita aggregate network structuram formatur. Ob esse de colloidal gel network structuram, et viscositas et aequilibrio repono moduli sunt et alta.

In structural transitus punctum T1, fractal dimensionem D2 guttae acriter a II ad I, decrescit unius ordinis magnitudinis. In acuti mutatio in D2 valorem indicat quod network structuram est resolutum in minor virga, sicut fragmenta. Hic status hic repraesentatur status II. Post acri transitus punctum T1, in D2 valorem paulatim decrescit, significans quod longitudinem virga paulatim breviora cum incremento ionomer γ. Toyota centralis Research Laboratory quod hoc longitudo determinari per statera inter electrostatic repulsu de adsorbed Ionomer et hydrophobic (vel dissipativa attraction) vi.

Cum adhuc incremento de ionomer adsorption Ratio γ, in D2 valorem paulatim decrescit ex I ad 0,5 vel minus. Hoc modo quod fragmenta collapse ad formam semotus aggregat per auctus electrostatic repulsive commercium causatur ab ulteriore Ionomer adsorption. Hunc diffinitur statum diffiditur. In hoc scaena, ibi est network structuram. Ergo catalyst slurry gerit ut newtonian liquid.

Ad determinare quod propria solvendo proprietatibus causa mutationes, Toyota Central Research Laboratory studied per correlationem inter slurry characteres et solvent characteres. Potest videri quod Ionomer ADSORPTIONGPTIONPTIONGIUM Ratio γ augetur cum augmentum in aqua pondus fractio. Hoc est quod hoc est quod hydrophilic solvent replet in hydrophobic ipsum fluorine fluorine in Ionomer et adsorbs ad Hydrophobic ipsum superficiem. Hoc quoque rationabiliter explicat parva effectus de platinum loading in Ionomer adsorption. Et effectus solvendo de catalyst slurry structuram potest efficaciter proprium per hansen solubility modularis hsp, Δp.

Ob super mechanism, incremento in Hsp, ΔP ducit ad augmentum in Ionomer adsorption Ratio γ. Ut ex aggregata collapse per repulsive interactiones, unde in decrementum in fractal dimensionem D2 de aggregata. Tandem, in Viscositas decrescit cum augendae Hsp, Δp. It is noteworthy that the observed correlation with HSP-δP can be approximately represented by a single line regardless of the type of alcohol present in the solvent, indicating that HSP-δP is a solvent characteristic parameter that effectively controls the aggregate structure and viscoelasticity of the catalyst slurry.

04

Summary

In hoc studio, Toyota explorat effectis solvent in viscoelasticity, ionomer adsorption rate et structural characteristics aggregata in catalyst slurries per mutationem in solvendo compositionem, et proposita in formatione mechanism aggregatorum in catalyst slurries.

In Suspendisse solvents ut aqua, solvendo replitatur hydrophobic ipsum, fluorine, in Ionomer, unde in ADSORPTIONPTION plurimi Ionomers onto in catalys particulis in Hydrophobic ipsum superficiem. In hoc casu, et sulfonic acidum coetus in adsorbed ionomers producendum electrostatic repulsive interactiones, unde in formatione bene-dispersit, rigidum, et dividitur aggregata ex PT / C catalysts cum magnitudine circiter CC NM. Etiamsi uniformiter dispersit, haec aggregata non potest esse amplius mechanice subdivaged in minor particulas. As the polarity decreases with increasing alcohol content, ionomers desorb from the surface of the aggregates, resulting in the formation of relatively short rod-like aggregates with a mass fractal dimension approaching 1. As the polarity decreases further, the ionomers continue to desorb, forming a colloidal gel network structure with a fractal dimension approaching 2. As the elastic gel network develops, both Viscositas et elasticitas augmentum. Omnes horum transitionum potest esse proprium hansen solubility hsp, Δp, quod repraesentat solvendo. Et supra studia indicant quod aggregate structuram et viscosity of Catalyst Slurries pro Proton Exchange membrana cibus cellulis potest disposito per moderantum solvent polarity proprium per Hsp, Δp.