Studies of propene oxidation over mixed uranium–antimony oxides

Abstract

Kinetic studies of the oxidation of propene over a uranium–antimony mixed oxide catalyst (U:Sb = 1:3), together with measurements of the a.c. electrical conductivity of the catalyst, have discriminated between some steps in the redox mechanism. Reduction of the catalyst (activation energy 50 ± 10 kJ mol^–1) and desorption of products are accompanied by increases in conductivity, although the initial adsorption of propene has the opposite effect. The conductivity decreases when the reduced catalyst is reoxidised (activation energy 180 ± 10 kJ mol^–1). Under reaction conditions, the overall rate is controlled by the production of labile oxygen species at the surface (activation energy 80 ± 1 kJ mol^–1).