Matching Items (3)
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- All Subjects: Fuel Cells
- Creators: Madakannan, Arunachalanadar
Description
Proton exchange membrane fuel cells have attracted immense research activities from the inception of the technology due to its high stability and performance capabilities. The major obstacle from commercialization is the cost of the catalyst material in manufacturing the fuel cell. In the present study, the major focus in PEMFCs has been in reduction of the cost of the catalyst material using graphene, thin film coated and Organometallic Molecular catalysts. The present research is focused on improving the durability and active surface area of the catalyst materials with low platinum loading using nanomaterials to reduce the effective cost of the fuel cells. Performance, Electrochemical impedance spectroscopy, oxygen reduction and surface morphology studies were performed on each manufactured material.
Alkaline fuel cells with anion exchange membrane get immense attention due to very attractive opportunity of using non-noble metal catalyst materials. In the present study, cathodes with various organometallic cathode materials were prepared and investigated for alkaline membrane fuel cells for oxygen reduction and performance studies. Co and Fe Phthalocyanine catalyst materials were deposited on multi-walled carbon nanotubes (MWCNTs) support materials. Membrane Electrode Assemblies (MEAs) were fabricated using Tokuyama Membrane (#A901) with cathodes containing Co and Fe Phthalocyanine/MWCNTs and Pt/C anodes. Fuel cell performance of the MEAs was examined.
Alkaline fuel cells with anion exchange membrane get immense attention due to very attractive opportunity of using non-noble metal catalyst materials. In the present study, cathodes with various organometallic cathode materials were prepared and investigated for alkaline membrane fuel cells for oxygen reduction and performance studies. Co and Fe Phthalocyanine catalyst materials were deposited on multi-walled carbon nanotubes (MWCNTs) support materials. Membrane Electrode Assemblies (MEAs) were fabricated using Tokuyama Membrane (#A901) with cathodes containing Co and Fe Phthalocyanine/MWCNTs and Pt/C anodes. Fuel cell performance of the MEAs was examined.
ContributorsKolli, Sri Harsha (Author) / Madakannan, Arunachalanadar (Thesis advisor) / Nam, Changho (Committee member) / Peng, Xihong (Committee member) / Arizona State University (Publisher)
Created2014
Description
Low temperature fuel cells are very attractive energy conversion technology for automotive applications due to their qualities of being clean, quiet, efficient and good peak power densities. However, due to high cost and limited durability and reliability, commercialization of this technology has not been possible as yet. The high fuel cell cost is mostly due to the expensive noble catalyst Pt. Alkaline fuel cell (AFC) systems, have potential to make use of non-noble catalysts and thus, provides with a solution of overall lower cost. Therefore, this issue has been addressed in this thesis work. Hydrogen-oxygen fuel cells using an alkaline anion exchange membrane were prepared and evaluated. Various non-platinum catalyst materials were investigated by fabricating membrane-electrode assemblies (MEAs) using Tokuyama membrane (# A201) and compared with commercial noble metal catalysts. Co and Fe phthalocyanine catalyst materials were synthesized using multi-walled carbon nanotubes (MWCNTs) as support materials. X-ray photoelectron spectroscopic study was conducted in order to examine the surface composition. The electroreduction of oxygen has been investigated on Fe phthalocyanine/MWCNT, Co phthalocyanine/MWCNT and commercial Pt/C catalysts. The oxygen reduction reaction kinetics on these catalyst materials were evaluated using rotating disk electrodes in 0.1 M KOH solution and the current density values were consistently higher for Co phthalocyanine based electrodes compared to Fe phthalocyanine. The fuel cell performance of the MEAs with Co and Fe phthalocyanines and Tanaka Kikinzoku Kogyo Pt/C cathode catalysts were 100, 60 and 120 mW cm-2 using H22 and O2 gases. This thesis also includes work on synthesizing nitrogen doped MWCNTs using post-doping and In-Situ methods. Post-doped N-MWNCTs were prepared through heat treatment with NH4OH as nitrogen source. Characterization was done through fuel cell testing, which gave peak power density ~40mW.cm-2. For In-Situ N-MWCT, pyridine was used as nitrogen source. The sample characterization was done using Raman spectroscopy and RBS, which showed the presence ~3 at.% of nitrogen on the carbon surface.
ContributorsShah, QuratulAin Jawed (Author) / Madakannan, Arunachalanadar (Thesis advisor) / Tamizhmani, Govindasamy (Committee member) / Macia, Narciso (Committee member) / Arizona State University (Publisher)
Created2012
Description
Proton exchange membrane fuel cells (PEMFCs) run on pure hydrogen and oxygen (or air), producing electricity, water, and some heat. This makes PEMFC an attractive option for clean power generation. PEMFCs also operate at low temperature which makes them quick to start up and easy to handle. PEMFCs have several important limitations which must be overcome before commercial viability can be achieved. Active areas of research into making them commercially viable include reducing the cost, size and weight of fuel cells while also increasing their durability and performance. A growing and important part of this research involves the computer modeling of fuel cells. High quality computer modeling and simulation of fuel cells can help speed up the discovery of optimized fuel cell components. Computer modeling can also help improve fundamental understanding of the mechanisms and reactions that take place within the fuel cell. The work presented in this thesis describes a procedure for utilizing computer modeling to create high quality fuel cell simulations using Ansys Fluent 12.1. Methods for creating computer aided design (CAD) models of fuel cells are discussed. Detailed simulation parameters are described and emphasis is placed on establishing convergence criteria which are essential for producing consistent results. A mesh sensitivity study of the catalyst and membrane layers is presented showing the importance of adhering to strictly defined convergence criteria. A study of iteration sensitivity of the simulation at low and high current densities is performed which demonstrates the variance in the rate of convergence and the absolute difference between solution values derived at low numbers of iterations and high numbers of iterations.
ContributorsArvay, Adam (Author) / Madakannan, Arunachalanadar (Thesis advisor) / Peng, Xihong (Committee member) / Liang, Yong (Committee member) / Subach, James (Committee member) / Arizona State University (Publisher)
Created2011