An Evaluation of the Ethanol Oxidation Activity of Ternary Pt-Rh-SnO2 catalysts Prepared from the Vapor Phase
Previous flame-based deposition of catalysts for ethanol oxidation have focused on Pt-Sn combinations and found that 10 wt.% Sn showed the best onset potential (~0.3V vs RHE) and largest oxidation peaks in 0.5 M H2SO4and 1 M ethanol at 1 mV/s .
Reactive spray deposition technology (RSDT) has been developed by Maric et al. to produce nanoparticles in vapor phase for catalysts comprised of Pt [7,8], IrxPt1-xO2-y, and IrxRu1-xO2-y . In this work we extend recent studies on Pd-Ru and Pd cores made by the RSDT process, with subsequent Pt monolayer attachment by galvanic displacement, to the ternary Pt/Rh/Sn system. Elemental ratios of 3:1:3 and 3:2:3 are examined for their performance toward ethanol oxidation. Figure 1 shows the nodular morphology of Pt/Rh/Sn (3:2:3) as grown on a gas diffusion layer along with the XEDS elemental mapping. Strategies for electrode activation using potential cycling in HClO4, ethanol and CO stripping are discussed. Figure 2 is a plot of the CV after various pre-treatment approaches. The performance toward ethanol oxidation at room temperature and 60oC will be discussed in respect to chemical composition. A representative linear sweep voltammogram is shown in Figure 3. Infrared reflection-absorption spectroscopy (IRRAS) is explored to detail the EOR mechanism. Microscopy studies of the structure and chemical composition are presented.
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