Pt Submonolayers on Ru Single-Crystal Surfaces

Adzic and coworkers proposed a radically new approach in electrocatalysis and catalysis that can alleviate both problems. It is based on a catalyst consisting of only a submonolayer Pt deposited on carbon-supported Ru nanoparticles. The Pt submonolayer on Ru (PtRu2o) electrocatalyst demonstrated higher CO tolerance than commercial catalysts in rotating disk experiments. Tests of the long-term stabihty of the fuel cells detected no loss in perform- 

Wieckowski et al. reported the spontaneous deposition Ru adlayers from RuO solutions on three low-index Pt surfaces. The maximum coverage of Ru on these adlayer is about 20%, and potential must be applied to reduce the Ru adlayer to metallic Ru. The Ru-decorated Pt nanoparticles showed considerable catalytic activity in the methanol- oxidation reaction. We will discuss the catalytic properties of the Ru-decorated Pt nanoparticles in Section V.3. 

The modulation in the vibrational frequency of CO on Pt-Ru is attributed to the charge transfer from Ru to Pt, due to difference in work function that weakens the Ru-CO bond and strengthens the Pt-CO bond. The weaker bonding of Ru-CO on Pt-Ru makes CO more reactive here than on pure Ru, and accordingly, electrooxidation sets in earlier in the potential scale. On the other hand. 

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