The role of the support in CO(ads) monolayer electrooxidation on Pt nanoparticles: Pt/WO(x)vs. Pt/C.
The electrocatalytic properties of home-made Pt nanoparticles supported onto WO(x) were determined for the electrooxidation of a CO(ads) monolayer and compared with that of a commercial Pt/C having the same Pt particle size. By combining electrochemical and spectroscopic techniques, we found that Pt/WO(x) nanoparticles exhibit a very high tolerance to CO at low electrode potentials (E = 0.1 V vs. RHE), which was never reported in the literature before. CO adsorption at E = 0.1 V vs. RHE on Pt/WO(x) yields CO(2) production as observed by Fourier-transform infrared spectroscopy (FTIR). When the gas bubbling in solution changes from CO to Ar, the current attenuates and the CO(2) production vanishes. This points towards a limited number of "active sites" and a slow step in the electrocatalytic process. When H(2) is used to purge the electrolyte from CO, a steep and continuous increase of the H(2) electrooxidation current is observed pointing towards continuous liberation of the Pt catalytic sites. The high tolerance to CO of Pt/WO(x) is discussed in terms of strong metal-support interaction (SMSI), which involves formation of a metal-oxide film partially covering the Pt nanoparticles (encapsulation) and creation of W-OH groups upon H(+) insertion at low electrode potentials.
Micoud
Fabrice
F
Laboratoire d'Electrochimie et de Physico-chimie des Matériaux et des Interfaces (LEPMI), UMR 5631 CNRS/UJF/Grenoble-INP, 1130 rue de la piscine, BP 75, 38402 Saint Martin d'Hères Cedex, France.
Maillard
Frédéric
F
Bonnefont
Antoine
A
Job
Nathalie
N
Chatenet
Marian
M