(771d) Development of Continuous Co-Electroless Deposition and Improvements Made to Catalyst Activity and Stability
This method was used to synthesize two classes of catalysts to demonstrate improved activity and increased catalyst stability. Methanol electrooxidation catalysts for DMFCs were synthesized by depositing Cu2+/Pt4+, Ni2+/Pt4+, and Co2+/Pt4+ onto Pd/C cores. By controlling ratio of M:Pt (where M is a non-Pt transition metal), maxima in activities were shown. All elemental compositions had Pt mass activity maxima over that of supported Pt/C alone. Additionally, shell compositions showing the highest activities matched those predicted by computational modeling of this reaction reported previously in the literature. The second class of catalysts were Ir@Pt-Ir /h-BN for a high temperature (800Â°C) decomposition reaction. The sintering behavior of Pt is widely reported and is made worse by weak interaction between Pt and support (as in the case with h-BN, a support lacking oxide species). Catalysts prepared by IWI tested under these conditions show rapid deactivation by means of Pt particle growth. However, catalysts made by the co-deposition of Pt and Ir together resisted Pt particle growth, evidenced by in situ XRD analysis under relevant high temperature, oxidizing conditions. This demonstrates a large improvement in catalyst stability (lifetime) over monometallic Pt and bimetallic Pt-Ir catalysts made by other methods.
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