Thermochemistry and reactivity of lattice oxygen in V-Sb oxide catalysts for the oxidative dehydrogenation of light paraffins

Differential scanning calorimetry is used to study in situ the properties of strongly bound (lattice) oxygen in vanadium-containing supported catalysts for the oxidative dehydrogenation of paraffins C-2-C-4. Evidence is found that the process occurs via a stepwise redox mechanism with the participation of lattice oxygen from the catalyst. When the supported component is modified by an antimony additive, the amount of reactive oxygen increases and redox processes accelerate. Simultaneously, the rate of coke formation decreases. Additional modification by Bi and Ba leads to a further increase in the amount of reactive oxygen. In all cases, oxygen bound to vanadium atoms is responsible for the redox properties of the systems. The observed effects are analyzed from the standpoint of the ratio between different forms of active oxygen.