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Article

Single Wall Carbon Nanotube Supports for Portable Direct Methanol Fuel Cells

Supporting Info

G. Girishkumar,^† Timothy D. Hall,^‡ K. Vinodgopal,*^†^§ and Prashant V. Kamat*^†^‡

Radiation Laboratory and Departments of Chemistry & Biochemistry and Chemical & Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556-0579, and Department of Chemistry, Indiana University Northwest, Gary, Indiana 46408

J. Phys. Chem. B, 2006, 110 (1), pp 107–114

DOI: 10.1021/jp054764i

Publication Date (Web): November 17, 2005

†

Radiation Laboratory, University of Notre Dame.

‡

Departments of Chemistry & Biochemistry and Chemical & Biomolecular Engineering, University of Notre Dame.

To whom correspondence should be addressed. E-mail: pkamat@nd.edu. Tel.: 574-631-5411. Fax: 574-631-8068.

Indiana University Northwest.

Abstract

Single-wall and multiwall carbon nanotubes are employed as carbon supports in direct methanol fuel cells (DMFC). The morphology and electrochemical activity of single-wall and multiwall carbon nanotubes obtained from different sources have been examined to probe the influence of carbon support on the overall performance of DMFC. The improved activity of the Pt−Ru catalyst dispersed on carbon nanotubes toward methanol oxidation is reflected as a shift in the onset potential and a lower charge transfer resistance at the electrode/electrolyte interface. The evaluation of carbon supports in a passive air breathing DMFC indicates that the observed power density depends on the nature and source of carbon nanostructures. The intrinsic property of the nanotubes, dispersion of the electrocatalyst and the electrochemically active surface area collectively influence the performance of the membrane electrode assembly (MEA). As compared to the commercial carbon black support, single wall carbon nanotubes when employed as the support for anchoring the electrocatalyst particles in the anode and cathode sides of MEA exhibited a 30% enhancement in the power density of a single stack DMFC operating at 70 °C.