Electrochemical Properties and Durability of Electrocatalysts Supported on SnO2

For polymer electrolyte fuel cells (PEFCs), carbon corrosion, leading to lower activities of catalysts under cathode conditions, is one of the important technological issues to be solved. We have been developing SnO2 and Nb-SnO2 as alternative support materials. In this study, the oxygen reduction reaction (ORR) activity and the durability of Pt/SnO2 and Pt/Sn0.98Nb0.02O2 against voltage cycling between 1.0 and 1.5 VRHE are quantitatively investigated. Longer ORR durability was verified, compared to the standard catalyst, Pt/Vulcan. Furthermore, we have found that the degradation mechanism of ORR is probably different between carbon black and SnO2-based supports. In the case of SnO2-based catalysts, degradation arose mainly from the loss of electrochemical surface area (ECSA), while other factors were also involved for Pt/Vulcan. Consequently, SnO2 is a promising candidate electrocatalyst support material to solve carbon corrosion problems of PEFCs.