We have recently demonstrated, and kinetically characterised, that a CO oxidation route to CO2 exists that is active at room temperature in Pt/Al2O3 catalysts. [1,2] This route has been shown to be mediated by reactive carbonate species that we have postulated to be hosted at atomic Pt sites that exist, and communicate with Pt nanoparticles also present in our catalysts. By using time resolved diffuse reflectance infrared spectroscopy (DRIFTS), extended X-ray absorbtion fine structure (EXAFS) spectroscopy, high energy X-ray diffraction (HXRD), total X-ray scattering/PDF, and small angle X-ray scattering (SAXS) we demonstrate that even at room temperature the nanoparticulate Pt structure is highly labile in a manner commensurate with the reactive chemistry detected using DRIFTS and mass spectroscopy (MS). As a result of these combined studies we discuss the roles of: atomic Pt species; changes in Pt nanoparticle morphology and size; and surface oxides formed on the nanoparticles, in facilitating the conversion of CO to CO2 at room temperature. A revised mechanism for this conversion, that exists outside the traditional Langmuir-Hinshelwood mechanism for CO conversion to CO on Pt/Al2O3 catalysts, is then discussed.

The secret life of Al2O3 supported platinum nanoparticles during CO/O2 redox cycling at room temperature and its relation to CO oxidation to CO2 at room temperature

256th National Meeting (2018)

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