ELECTROCATALYSIS BY AD-ATOMS: PART XIII. PREPARATION OF AD-ELECTRODES WITH TIN AD-ATOMS FOR METHANOL, FORMALDEHYDE AND FORMIC ACID FUEL CELLS.

The practical application of electrocatalysis by tin ad-atoms to organic fuel cell anodes has been studied. A simplified and versatile preparation method of the electrode having high specific surface area platinum with a well-defined tin coverage has been developed. It consists of underpotential deposition of ad-atoms and subsequent anodic treatment resulting in uniform dipersion of the ad-atoms over all the platinum clusters in the catalyst layer of the electrode. The resulting electrode exhibits enhancement effects in the specific activity over the pure platinum black electrode by a factor of 100 for methanol oxidation, of more than 1000 for formaldehyde oxidation and of 250 for formic acid oxidation, respectively. This method has the advantage that a much higher specific surface area of catalyst is obtained, as well as an optimum composition, compared with the electrochemical co-deposition or immersion methods proposed previously.