Modification of carbon supported catalysts to improve performance in gas diffusion electrodes

The effect of surface oxidation of the carbon support of Pt catalysts with nitric acid has been investigated. Oxidation of the support before depositi on of the Pt leads to a decrease in the Pt particle size, as reported by ot hers, and enhanced performance for oxygen reduction in gas diffusion electr odes. Oxidation of the support after Pt deposition produces an even greater enhancement in performance, which we have attributed to enhanced proton co nductivity in the catalyst layer. It is speculated that hydrophilic carboxy lic acid groups produced by surface oxidation enhance wetting of the cataly st layer. (C) 2001 Elsevier Science Ltd. All rights reserved.