Over the last years, the attention towards the power generation technologies with low environmental impact has substantially risen. In this context, the Proton Exchange Membrane Fuel Cells (PEMFC) technology, which convert the electrochemical energy of the reactants directly into electricity without passing through combustion processes, is proposed as a promising candidate for use in automotive industry, in stationary power generation and portable devices, because of their use of renewable energy sources, the absence of greenhouse gas emissions and the high theoretical efficiencies obtainable. In this paper, we present an experimental analysis focused on the study of performances of PEMFCs with reduced catalyst loading, during their degradation: this survey is divided into three different test campaigns. The first experimental investigation is focused on the influence of the cathodic catalyst loading and of the carbon catalyst support on performances and degradation of PEMFC: MEAs are used with three different platinum catalyst loading (0.05 mg/cm2, 0.1 mg/cm2 and 0.2 mg/cm2), and with two different carbon supports (Ketjen Black and Multi-Walled Carbon NanoTubes), in order to highlight the differences in performances during the induced degradation procedure. The second experimental investigation is focused on the influence of the average size of the platinum particles used as catalyst: we used three PEMFCs with different average particle size (2nm, 3nm, 5nm, 2nm + 5nm), in order to find an experimental bond between this particle size and performances during the PEMFCs useful life. The third experimental campaign is focused on the effect of humidification of the two electrodes during the degradation procedure: three equal PEMFCs are subjected to different induced degradation procedures (fully humidified flows, injection of liquid water to the cathode side, injection of liquid water to the anode side), in order to highlight the performance diversity during their degradation. Along with this experimental analysis, we developed a modelling study, based on the Double-trap model, in order to characterize the behaviour of the PEMFC fundamental reactions kinetics during induced degradation.
Negli ultimi anni, l’attenzione verso le tecnologie di generazione di potenza a basso impatto ambientale e ad alta efficienza è aumentata sensibilmente. In questo contesto, la tecnologia delle celle a combustibile polimeriche Proton Exchange Membrane Fuel Cells (PEMFC), che convertono l’energia chimica dei reagenti direttamente in energia elettrica senza passare per processi di combustione, si propone come candidato promettente per impieghi nel settore automobilistico, nella generazione stazionaria di potenza e per dispositivi portatili, in virtù del loro impiego di fonti di energia rinnovabili, dell’assenza di emissioni di gas serra e per le alte efficienze teoriche ottenibili. In questo lavoro è trattata un’analisi sperimentale mirata sullo studio prestazionale di PEMFC a ridotto carico catalitico durante la loro degradazione: tale indagine è suddivisa in tre diverse campagne sperimentali. La prima indagine sperimentale è concentrata sull’influenza del carico catalitico al lato catodico e del supporto carbonioso sulle prestazioni e sulla degradazione delle PEMFC: sono utilizzate MEA con tre diversi carichi catalitici di platino (0.05 mg/cm2, 0.1 mg/cm2 e 0.2 mg/cm2), e con due diversi supporti carboniosi (Ketjen-Black e Multi Walled Carbon NanoTubes), in modo da evidenziare le differenze prestazionali durante la procedura di degradazione indotta. La seconda indagine sperimentale è concentrata sull’influenza della dimensione media delle nanoparticelle di platino usato come catalizzatore: si utilizzano quindi PEMFC con diverse dimensioni medie (2nm, 3nm, 5nm, 2nm+5nm), in modo da trovare un legame sperimentale tra la dimensione media e le prestazioni nell’arco della vita utile. La terza campagna sperimentale è concentrata sull’effetto dell’umidificazione dei due elettrodi durante la procedura di degradazione: si utilizzano tre PEMFC uguali tra loro, e si sottopongono a diverse procedure di degradazione indotta (flussi completamente umidificati, iniezione di acqua liquida al lato catodico, iniezione di acqua liquida al lato anodico), evidenziandone le diversità prestazionali durante il degrado. Insieme a questa analisi sperimentale si è trattato anche uno studio modellistico, basato sul modello del Double Trap, in modo da poter caratterizzare il comportamento delle cinetiche delle reazioni fondamentali della PEMFC durante la degradazione indotta,
Studio della degradazione di PEMFC : effetto del carico di platino, della dimensione delle nanoparticelle e del supporto
VILLA, GIOVANNI;MANGOGNA, ANTONIO
2014/2015
Abstract
Over the last years, the attention towards the power generation technologies with low environmental impact has substantially risen. In this context, the Proton Exchange Membrane Fuel Cells (PEMFC) technology, which convert the electrochemical energy of the reactants directly into electricity without passing through combustion processes, is proposed as a promising candidate for use in automotive industry, in stationary power generation and portable devices, because of their use of renewable energy sources, the absence of greenhouse gas emissions and the high theoretical efficiencies obtainable. In this paper, we present an experimental analysis focused on the study of performances of PEMFCs with reduced catalyst loading, during their degradation: this survey is divided into three different test campaigns. The first experimental investigation is focused on the influence of the cathodic catalyst loading and of the carbon catalyst support on performances and degradation of PEMFC: MEAs are used with three different platinum catalyst loading (0.05 mg/cm2, 0.1 mg/cm2 and 0.2 mg/cm2), and with two different carbon supports (Ketjen Black and Multi-Walled Carbon NanoTubes), in order to highlight the differences in performances during the induced degradation procedure. The second experimental investigation is focused on the influence of the average size of the platinum particles used as catalyst: we used three PEMFCs with different average particle size (2nm, 3nm, 5nm, 2nm + 5nm), in order to find an experimental bond between this particle size and performances during the PEMFCs useful life. The third experimental campaign is focused on the effect of humidification of the two electrodes during the degradation procedure: three equal PEMFCs are subjected to different induced degradation procedures (fully humidified flows, injection of liquid water to the cathode side, injection of liquid water to the anode side), in order to highlight the performance diversity during their degradation. Along with this experimental analysis, we developed a modelling study, based on the Double-trap model, in order to characterize the behaviour of the PEMFC fundamental reactions kinetics during induced degradation.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/118301