Redox behaviour of thermally activated platinum electrodes with particularreference to operation at elevated temperature

The present work is a continuation of an earlier investigation of the effec t of severe thermal pretreatment on the redox properties of platinum electr odes in aqueous media. The most interesting observation was that raising th e solution temperature to ca. 75 degrees C resulted in a dramatic anodic re sponse in the positive sweep at ca. 0.25 V (RHE). Such behaviour was noted earlier at room temperature but only when the thermally pretreated sample w as further activated by cathodic polarization. This transition at 0.25 V wa s partially reversed on the negative sweep, but the cathodic process involv ed was subject to severe inhibition. There is independent evidence for simi lar behaviour for gold in aqueous acid solution. The relevance of the prese nt results to the operation of fuel cell anodes is outlined.