Date of Graduation

Fall 2009

Degree

Master of Science in Materials Science

Department

Physics, Astronomy and Materials Science

Committee Chair

Kartik Ghosh

Keywords

fuel cells, carbon nanotubes, graphene, platinum and platinum-ruthenium catalysts, electrocatalytic activity

Subject Categories

Materials Science and Engineering

Abstract

Alternative energy conversion systems are receiving great attention due to the depletion of fossil fuels and increasing environmental pollution. Due to excellent features such as high energy density, low operating temperature, and high energy conversion efficiency, direct methanol (DMFC) and ethanol fuel cells (DEFC) are promising power sources to address future energy problems. However, their performance is limited by low electrocatalytic activity of anodes for methanol and ethanol oxidations, and the high cost of noble metal platinum (Pt) based catalysts. One approach to enhance catalytic activity and to reduce the cost is to explore novel carbon materials as catalyst supports. In this work, single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), and graphene-supported Pt and Pt-Ru catalysts were synthesized by an ethylene glycol (EG) reduction method. Comparative electrochemical measurements of different carbon structure-supported catalysts were conducted using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry techniques. Experimental results show that SWCNT-supported Pt and Pt-Ru catalysts have a higher catalytic activity and lower charge transfer resistance towards methanol and ethanol oxidation in comparison to MWCNT-supported catalysts. The electrocatalytic activities of graphene-supported catalysts were compared with commercial Vulcan XC-72 carbon black-supported catalysts and graphite supported catalysts. Experimental results suggest that graphene-supported Pt and Pt-Ru nanoparticles possess superior electrocatalytic activity than carbon black and graphite supports.

Copyright

© Raghavendar Reddy Sanganna Gari

Campus Only

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