Development of different carbon supports for proton exchange membrane fuel cell electrocatalysts

Download
index.pdf
2010
Güvenatam, Burcu
Show full item record
259
views
101
downloads
Proton exchange membrane (PEM) fuel cell technology is promissing alternative solution to today’s energy concerns providing clean environment and efficient system. Decreasing platinum (Pt) content of fuel cell is one of the main goals to reduce high costs of fuel cell technology in the way of commercialization. In this target, porous carbons provide an alternative solution as a support material for fuel cell electrocatalysts. It is also essential to increase surface area of carbon support material to have well dispersion of the Pt nanoparticles. The aim of this thesis is to synthesize mesoporous carbon supports named as hollow core mesoporous shell (HCMS) carbon and prepare their corresponding electrocatalysts with platinum impregnation method. HCMS carbon supports were synthesized by using two different carbon sources. As a first approach, phenol/paraformaldehyde couples were used and carbon source exhibited 1053 m 2 /g BET surface area and 1.046 nm BJH adsorption pore diameter. Second approach was to use divinylbenzene (DVB) as a carbon source with an initiator named as azo bis isobuytronitrile (AIBN) differing synthesis criteria. It is observed that using AIBN/DVB, pore sizes increased up to 3.44 nm. Platinum impregnation was conducted by microwave irradiation method using hydrogen hexachloroplatinate (IV) hydrate as a platinum precursor. The first achievement was to increase platinum loading up to 44 wt % on commercial Vulcan XC 72 by using ethylene glycol as a reducing agent. Using different reducing agents such as hydrazine, sodium borohydrate with a combination of ethylene glycol, platinum loading reached up to 34 wt % on HCMS carbon support. Accordingly, 34 wt %, 32 wt % and 28 wt % Pt/HCMS carbon supported electrodes preparation was achieved. The sizes of the platinum nanoparticles were calculated by XRD analysis as 4 nm, 4.2 nm and 4.5 nm for 28 wt %, 32 wt % and 34 wt % Pt/HCMS carbon supported electrodes respectively. Characterizations of catalysts were performed by ex situ (N 2 adsorption, TGA, SEM, TEM and Cyclic Voltammetry) and in situ (PEMFC tests) analysis.
Chemical engineering.
http://etd.lib.metu.edu.tr/upload/12612376/index.pdf
https://hdl.handle.net/11511/19926
Graduate School of Natural and Applied Sciences, Thesis

Suggestions

Removal of hydrogen sulfide by regenerable metal oxide sorbents
Karayılan, Dilek; Doğu, Timur; Department of Chemical Engineering (2004)
High-temperature desulfurization of coal-derived fuel gases is an essential process in advanced power generation technologies. It may be accomplished by using metal oxide sorbents. Among the sorbents investigated CuO sorbent has received considerable attention. However, CuO in uncombined form is readily reduced to copper by the H2 and CO contained in fuel gases which lowers the desulfurization efficiency. To improve the performance of CuO-based sorbents, they have been combined with other metal oxides, form...
Development of organic-inorganic composite membranes for fuel cell applications
Erdener, Hülya; Baç, Nurcan; Department of Chemical Engineering (2007)
Hydrogen is considered to be the most promising energy carrier of the 21st century due to its high energy density and sustainability. The chemical energy of hydrogen can be directly converted into electricity by means of electrochemical devices called fuel cells. Proton exchange membrane fuel cells (PEMFC) are the most preferred type of fuel cells due to their low operating temperatures enabling fast and easy start-ups and quick responses to load changes. One of the most important components of a PEMFC is t...
Preparation and performance of membrane electrode assemblies with nafion and alternative polymer electrolyte membranes
Şengül, Erce; Eroğlu, İnci; Department of Chemical Engineering (2007)
Hydrogen and oxygen or air polymer electrolyte membrane fuel cell is one of the most promising electrical energy conversion devices for a sustainable future due to its high efficiency and zero emission. Membrane electrode assembly (MEA), in which electrochemical reactions occur, is stated to be the heart of the fuel cell. The aim of this study was to develop methods for preparation of MEA with alternative polymer electrolyte membranes and compare their performances with the conventional Nafion® membrane. Th...
Effect of preparation and operation parameters on performance of polyethersulfone based mixed matrix gas separation membranes
Karatay, Elif; Yılmaz, Levent; Department of Chemical Engineering (2009)
Membrane processes have been considered as promising alternatives to other competing technologies in gas separation industry. Developing new membrane morphologies are required to improve the gas permeation properties of the membranes. Mixed matrix membranes composing of polymer matrices and distributed inorganic/organic particles are among the promising, developing membrane materials. In this study, the effect of low molecular weight additive (LMWA) type and concentration on the gas separation performance o...
Synthesis of some metalophthalocyanines and their effects on the performance of pem fuel cells
Erkan, Serdar; Eroğlu, İnci; Department of Chemical Engineering (2005)
Importance of clean, sustainable and renewable energy sources are increasing gradually because of either being environmental friendly or being alternative for fossil fuels. Hydrogen energy system will let the utilization of alternative energy sources. Fuel cells are the most suitable energy conversion devices while passing through the hydrogen economy. The cost of the fuel cell systems need to be reduced in order to achieve commercialization of these systems. One of the most important cost items is platinum...
Citation Formats
B. Güvenatam, “Development of different carbon supports for proton exchange membrane fuel cell electrocatalysts,” M.S. - Master of Science, Middle East Technical University, 2010.
METU IIS - Integrated Information Service open@metu.edu.tr