Chromium oxide deposited on phosphorusloaded alumina is used in the oxidative dehydrogenation (ODH) of propane to propylene. Operando Raman-GC studies allowed evaluating the molecular structure of surface Cr oxide species, their reactivity and their changes undergone during operation. The addition of phosphorous to the alumina substrate decreases propane conversion, mainly due to the decrease of COx, there is a concomitant increase in the selectivity to propylene formation. The addition of phosphorous affects the nature of the Cr oxide species, which do not form of a new phase. The surface interaction between dispersed chromate species and phosphorous weakens the Cr=O bond and retards the aggregation of surface chromate species as Cr 2O3 during reaction in ca. 170 °C.
- Oxidative dehydrogenation