PEMFC commercialization is currently precluded because of costly Pt catalysts required to accelerate the sluggish oxygen reduction reaction (ORR).  The concomitant use of hydrogen fuel to prevent catalyst de-activation by strongly adsorbed species such as CO further impacts the sustainability of this Pt-based technology due to the need for high-energy purification (to less than 10 ppm CO) as well as an entirely new high-pressure storage and delivery infrastructure. Previous single crystal studies have demonstrated that Pt surface poisoning by intermediates produced during the ethanol oxidation reaction (EOR) can be mitigated by the presence of Sn atoms.  Pt(110) exhibited the highest anodic current at optimum Sn coverage.  Our own recent work with highly dispersed nanoparticles demonstrated the surface active site distribution is dominated by stepped Pt(110) and Pt(311) surfaces.    Optimum Sn coverage on such nanoparticle structures was found comparable to that on single crystals.  Sn coverage was controlled by means of a unique, one-beaker, all-aqueous stannous chloride-ligand-based synthesis approach.We here present results concerning the structure dependency of the EOR for Pt-Ru-Sn nanoparticles with a similarly adsorbed stannous chloride ligand shell.  Chronoamperometry measurements at 0.45 V in 0.5 M ethanol/0.5 M H2SO4 at room temperature demonstrate significant improvement in the long-term EOR activity loss for the Pt-Ru-Sn core-shell nanoparticles relative to Sn-free and commercial nanoparticles. Importantly, the use of our technique to synthesize Pt-Ru-Sn nanoparticles demonstrates that this synthesis technique can be extended to other, potentially more sustainable metals and for mutli-shell synthesis.

Electrocatalytic ethanol oxidation on Pt-Ru-SnO nanoparticles

246th National Meeting (2013)

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