Nanostrutured Electrocatalysts for Methanol and Ethanol-Tolerant Cathodes
Polymer electrolyte membrane fuel cells (PEMFC) that use small organic molecules like methanol and ethanol as fuel in the anode, and oxygen in the cathode, are attracting considerable interest for application in portable electronic devices. Carbon-supported platinum has the highest catalytic activity for oxygen reduction when compared to all other pure metals, and serves as state-of-the-art cathode material in low-temperature fuel cells. Regarding the direct methanol or ethanol fuel cells (DMFC or DEFC), one of the major problems is the alcohol crossover through the polymer electrolyte. The mixed potential, which results from the oxygen reduction reaction and the alcohol oxidation occurring simultaneously, reduces the cell voltage, generates additional water and increases the required oxygen stoichiometric ratio. This problem can be, in principle, solved either by using electrolytes with lower methanol or ethanol permeability or by developing new cathode electrocatalysts with both higher alcohol tolerance and higher activity for the oxygen reduction reaction than Pt. This chapter presents an overview of recent developments of platinum and non-platinum-based catalysts as methanol and ethanol-tolerant oxygen reduction materials for direct alcohol fuel cells.
KeywordsFuel Cell Oxygen Reduction Reaction Methanol Oxidation Direct Methanol Fuel Cell Oxygen Reduction Reaction Activity
E. A. Ticianelli and F. H. B. Lima acknowledge support from Fundação de Amparo à Pesquisa do Estado de São Paulo – FAPESP, Brazil.
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