doktorska disertacija
Maša Hren (Author), Selestina Gorgieva (Mentor)

Abstract

Gorivne celice so obetavne naprave za neposredno pretvorbo kemijske energije v električno s potencialno aplikacijo na številnih področjih, vendar komercializacijo trenutno najbolj razvitih vodikovih gorivnih celic ovira visok strošek nekaterih komponent, kot so katalizatorji na osnovi platine. Kot ekonomsko bolj ustrezna alternativa se razvijajo alkalne gorivne celice (AAEMFC), ki kot trdni polielektrolit med elektrodama uporabljajo anionsko izmenjevalno membrano (AEM). Trenutne komercialno razpoložljive AEM, so drage in osnovane na sintetičnih polimerih, njihova priprava pa je navadno kompleksna in okolju neprijazna, kar nakazuje na potrebo po razvoju novih visoko učinkovitih, preprostih za pripravo, okolju prijaznih in ekonomsko sprejemljivih AEM. Doktorska disertacija se osredotoča na razvoj novih biopolimernih AEM na osnovi hitozana (CS) z organskimi vključki nanofibrilirane celuloze (CNF), funkcionalizirane CNF (CNF(D) in CNF(P)) in anorganskega N-dopiranega grafenovega oksida (N-GO). Funkcionalizacijo CNF z namenom uvedbe pozitivnega naboja, ki ga prispevajo kvaterne dušikove skupine, smo izvedli z uporabo organosilanskega reagenta DMAOP in polikationskega reagenta PDDA ter dobljene produkte CNF(D) in CNF(P), uporabne kot vključke, analizirali z metodami ATR-FTIR, 13C NMR in 29Si spektroskopijo, FE-SEM, TGA, DSC analizo, meritvami zeta potenciala in s polielektrolitsko titracijo, ter jih vključili v CS membrane. Za izbiro najobetavnejših AEM za vključitev v AAEMFC smo uporabili eksperimentalni načrt in pripravili serije CS membran s posameznimi vključki, ki smo jih okarakterizirali glede na ionsko prevodnost, kapaciteto ionske izmenjave, prehajanje goriva, navzemanje alkalije in nabrekanje, ter jih analizirali z metodami ATR-FTIR, SEM, TGA, XRD in določili mehanske lastnosti. S celičnim testom najobetavnejših AEM v AAEMFC smo ugotovili, da imajo pripravljene CS membrane z vključki N-GO (Pmax = 149 mW cm-2), CNF (Pmax = 62 mW cm-2), CNF(P) (Pmax = 62 mW cm-2) ter kombiniranima CNF in CNF(P) (Pmax = 65 mW cm-2) višje Pmax, kot komercialna membrana Fumatech (Pmax = 35 mW cm-2), s čimer smo identificirali njihov potencial za uporabo v AAEMFC.

Keywords

alkalna gorivna celica;anionsko izmenjevalna membrana;hitozan;vključki;nanofibrilirana celuloza;grafenov oksid;doktorske disertacije;

Data

Language: Slovenian
Year of publishing:
Typology: 2.08 - Doctoral Dissertation
Organization: UM FS - Faculty of Mechanical Engineering
Publisher: [M. Hren]
UDC: 544.726:547.458.81.022.524(043.3)
COBISS: 128768771 Link will open in a new window
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Downloads: 1
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Other data

Secondary language: English
Secondary title: Fabrication of chitosan based composite membranes with functionalized nanofibrillated cellulose for fuel cell applications
Secondary abstract: Fuel cells are promising devices for the direct conversion of chemical energy into electrical energy, with potential applications in many fields. Still, the commercialisation of the hydrogen fuel cells most frequently developed today has been hampered by the high cost of some components, such as platinum-based catalysts. Alkaline fuel cells (AAEMFCs) are being developed as a more economically viable alternative, using an anion exchange membrane (AEM) as a solid polyelectrolyte between the electrodes. Current commercially available AEMs, based on synthetic polymers, are expensive, and their preparation is usually complex and environmentally unfriendly, indicating the need to develop new highly efficient, easy-to-prepare, environmentally friendly, and economically acceptable AEMs. This doctoral dissertation focuses on the development of new chitosan-based biopolymer AEMs (CS) with organic inclusions of nanofibrillated cellulose (CNF), functionalized CNF (CNF (D), and CNF (P)), and inorganic inclusions of N-doped graphene oxide (N-GO). CNF functionalization was performed using organosilane reagent DMAOP and polycation reagent PDDA, with the aim of introducing a positive charge, contributed by quaternary ammonium groups. The obtained products CNF (D) and CNF (P), useful as inclusions, were analysed by ATR-FTIR, 13C NMR and 29Si spectroscopy, FE-SEM, TGA, DSC analysis, zeta potential measurements, and polyelectrolyte titration, and were incorporated into CS membranes. To select the most promising AEMs for inclusion in an AAEMFC, we used an experimental design and prepared a series of CS membranes with specified inclusions, which were characterised according to ionic conductivity, ion exchange capacity, fuel permeability, alkali uptake, and swelling, and were analysed through ATR-FTIR, SEM, TGA, XRD and mechanical properties determination. A cell test of the most promising AEMs in an AAEMFC showcased that the prepared CS membranes with inclusions of N-GO (Pmax = 149 mW cm-2), CNF (Pmax = 62 mW cm-2), CNF(P) (Pmax = 62 mW cm-2) and combined CNF and CNF(P) (Pmax = 65 mW cm-2) exhibited higher Pmax than the commercial Fumatech membrane (Pmax = 35 mW cm-2), thus identifying their potential for use in AAEMFCs.
Secondary keywords: alkaline fuel cell;anion exchange membrane;chitosan;inclusions;nanofibrillar cellulose;graphene oxide;Univerzitetna in visokošolska dela;
Type (COBISS): Doctoral dissertation
Thesis comment: Univ. v Mariboru, Fak. za strojništvo
Pages: XXI, 166 str.
ID: 15431458