Composite electrocatalysts for anodic methanol and methanol-reformate oxidation

Binary anode electrocatalyst formulations were prepared by adsorption of ph thalocyanine and tetraphenylporphyrin complexes of different transition met als on a commercial carbon supported platinum catalyst. Only after pyrolyzi ng the complexes at 700 degreesC under nitrogen were catalysts of some acti vity obtained. A binary Pt/Ni electrocatalyst prepared by this procedure ex hibits considerable anodic catalytic activity in the acidic environment of the Nafion(R) electrolyte for reformate and direct methanol oxidation for m ore than 400 h without deterioration. Ternary electrocatalyst formulations Pt/Ru/W = 1/1/y were produced according to the Bonnemann method. The Pt/Ru/ W catalyst of 1/1/1.5 (mol/mol/mol) composition is optimal. Compared to the Pt/Ru catalyst, it enhances the performance of reformate (H-2 + 150 ppm CO ) fuel cells by 50% and of direct methanol fuel cells (steam/methanol vapou r = 50:1 mol/mol) by 80%. Attached to a GC electrode by a thin Nafion(R) fi lm, the catalysts were also tested for methanol oxidation in aqueous methan ol solutions in half cells by slow potential stepping. This procedure is us eful for fast initial screening.