Probing electronic and atomic ensembles effects on PtAu3 nanoparticles with CO adsorption and electrooxidation

We have studied the adsorption and electrooxidation of CO on PtAu3 nanoalloys, aiming at providing further insight about the correlation between atomic structure and catalytic properties. The multiplicity of adsorption sites with different geometry and composition on the nanoparticles surface is demonstrated by a combination of electrochemical and infrared experiments. Specifically, the occurrence of low- and high-coordinated Pt atoms was confirmed by the splitting of the linearly-bonded CO band after removing CO from the electrolyte. Despite the low activity for the electrooxidation of COad of our PtAu3 nanoparticles, the combination of small Pt(111) terraces and small Pt atomic ensembles on their surfaces revealed by our experiments is connected with the negligible CO poisoning and the resulting high catalytic activity of our PtAu3 NPs for the formic acid oxidation reaction [Electrochim. Acta 2017, 224, 56–63].