Loss of surface area by platinum and supported platinum black electrocatalyst

The loss of surface area and performance of platinum black, platinum/Sb doped SnO2 and Pt/C electrode at 150°C, 85% H3PO4 were studied as a function of time and compared with results on electrodes subjected to 150°C heating only. The unsupported Pt black electrode suffered a significant loss in surface area and performance, especially when it was in contact with H3PO4. On the other hand, Pt/Sb doped SnO2 electrode remained unchanged at 150°C and only showed a slight drop in surface area and performance when it was in contact with H3PO4. The results suggest that solution and reprecipitation of Pt crystallites is the main predominant growth mechanism and that the use of suitable high surface energy support may help to reduce the rate of growth of Pt crystallites under such conditions.