Solubility of platinum in acidic media (I) - in sulfuric acid

Platinum depositions have been observed in the electrolyte membrane of polymer electrolyte fuel cells (PEFCs) as in other types of fuel cells; PEFCs, MCFCs. The platinum solubility in the membrane must be a key issue to improve and guarantee the durability of PEFCs. In this basic study, the platinum solubility has been determined in an acidic medium as a function of temperature, pH, and potential which was controlled by the oxygen partial pressure. The solubility was 3.0 x 10(-6) mol dm(-3) at 23 degrees C in I mol dm(-3) H2SO4 under air, and increased with temperature and the decrease in pH. The platinum solubility slightly increased with the oxygen partial pressure in oxygen-nitrogen mixtures. However, the solubility in nitrogen was much smaller than the mixtures. Based on these results, the dissolution of platinum in an acidic medium would follow the acidic dissolution mechanism.