The Platinum-on-Carbon Catalyst System for Hydrogen Anodes

The large differences in the activity of platinum‐on‐carbon anodes that could be produced by the choice of carbon indicated that an important chemical interaction existed between the platinum and the carbon surface. A chemical interaction was also indicated by electron‐spin‐resonance measurements on plain and platinized carbon. Subsequently it was found that the activity of the platinum anode was reduced to negligible values if the carbon surface was cleaned in N 2 at 1000°C before application of the platinum. If the carbon was reoxidized using at 1000°C before application of the platinum, full activity of the platinum deposit was obtained. The effect of N 2 and was reversible. Graphitic carbons were unsuitable for this work and did not respond greatly to these treatments. These effects do not seem to be explainable by the surface area changes that are produced. The effect appears to be explainable by adapting the catalyst poisoning theory of Maxted.