Testing Different Catalysts for a Vapor-Fed PBI-Based Direct Ethanol Fuel Cell

Abstract

With the aim of improving the ethanol oxidation in fuel cells, researchers have developed numerous catalysts to break up the C-C bond. Most of the tests have been carried out at low temperature, using Nafion membrane as electrolyte. The cell performance of the Direct Ethanol Fuel Cells (DEFCs) at low temperature is still far from its industrial application. To improve the DEFC power density, high temperature operation (150–200 °C) has been suggested to promote the complete oxidation of ethanol. Thus, three different catalysts (Pt-Ru (1:1), Pt-Sn (1:1) and Pt-Sn-Ru (1:1:0.3), all of them supported on both non-activated and activated carbon were tested in H3PO4 doped PBI-based fuel cell, using vapour fed ethanol, operating in the range of 150–200 °C, and high ethanol concentration 6.7 M. The catalyst were synthesized using NaBH4 as reducing agent and were characterized by XRD, ICP-AES and TPR analyses. The best performance was reached at the highest temperature and with the catalyst based on Pt-Ru. The best results for the Ru-based catalyst can be explained by the higher level of alloying reached for the Ru than for Sn, which modifies the crystalline structure of Pt and enhances the activity oxidation of ethanol and of intermediates that are generated during the oxidation of ethanol.

Key findings

• ▸The Pt-Ru catalyst showed the best performance at the highest temperature.
• ▸The Ru-based catalyst had a higher level of alloying, modifying the crystalline structure of Pt.
• ▸The best results for the Ru-based catalyst were due to the higher level of alloying compared to Sn.

Keywords

Identifiers

DOI

10.1115/fuelcell2009-85055

Journal

ASME 2009 7th International Conference on Fuel Cell Science, Engineering and Technology

Year

2008