Decomposition of CCl3F over vanadium oxides and [MgVxOy]MgO shell/core-like particles

Decomposition of gaseous CCl3F over in-house-prepared V2O3 (HP-V2O3), commercial V2O3, VO2, V2O5, a mechanical mixture of the HP-V2O3/Aerogel-prepared MgO (AP-MgO), and [MgVxOy]MgO shell/core-like particles at 280 °C has been investigated with FTIR spectroscopy. The reaction of CCl3F with the HP-V2O3 proceeds vigorously. Intermediate compounds including CCl4, CCl2F2, CCl2O, and final gaseous products CClF3, CO2 were detected. No chloride/fluoride was found on the sample surface, suggesting the formation of volatile vanadium–halogen products as well. Vanadium–chloride product was found to react with the surface of the bare AP-MgO leading to deposition of vanadium–chloride species. Activities of VO2 and V2O3 were found to be qualitatively similar to the HP-V2O3. The reaction of CCl3F with V2O5 proceeds much slower, with only CCl2O and CO2 gaseous products observed. Activation of the AP-MgO with vanadium-containing species leads to formation of [MgVxOy]MgO shell/core-like particles. The MgO crystalline phase was the only one detected in the [MgVxOy]MgO samples. In the reaction with CCl3F, the [MgVxOy]MgO samples retain some properties characteristic for the bare AP-MgO (presence of an induction period for V/Mg=1 mol%, lower activity toward CCl4 than toward CCl2F2 for V/Mg=1, 10 mol%), and some properties characteristic for the HP-V2O3/AP-MgO mechanical mixture (accumulation of chlorine but no fluorine on the [MgVxOy]MgO, V/Mg=10 mol% sample surface).