Stability and Activity of Pt/ITO Electrocatalyst for Oxygen Reduction Reaction in Alkaline Media

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Because of the activity for carbon materials to rapidly form peroxide-like species in alkaline media which cause considerable membrane degradation, there is a significant need to find stable non-carbon support materials for Pt and other oxygen reduction reaction (ORR) catalysts. The objective of this study was to investigate the performance of platinum supported on tin-doped indium oxide (ITO) electrocatalysts for the ORR in alkaline media. Platinum was deposited onto ITO by galvanic displacement and the Pt/ITO was physically characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Electrochemical experiments showed that Pt/ITO catalysts outperform commercial Pt/Vulcan in terms of both activity and stability. The specific activity and mass activity of Pt/ITO were about 2.5 times that of Pt/Vulcan. After 300 potentiometric cycles in O2-saturated alkaline electrolyte, only 17.4% loss in the electrochemical surface area (ECSA) was observed for Pt/ITO, which compares favorably to Pt/Vulcan at 37.5%. The good durability of Pt/ITO at a relatively high specific activity provides one of the first examples of successful deployment of a non-carbon support for anion exchange membrane fuel cell catalysts.