Characterization and Deactivation Study of Mixed Vanadium and Potassium Oxide Supported on Microemulsion-Mediated Titania Nanoparticles as Catalyst in Oxidative Dehydrogenation of Propane

Abstract

Abstract The influence of potassium addition to the vanadia supported on the microemulsion-mediated TiO2 nanoparticles in propane oxidative dehydrogenation was studied. Raman spectroscopy demonstrated that the addition of potassium caused enhanced dispersion of vanadia species on the support surface. Also, potassium existence affects the H2 temperature programmed reduction maximum reduction temperature and shifted it to 520°C, which was in accordance with its lesser catalytic activity. Nevertheless, a propylene selectivity enhancement was observed by potassium addition. In spite of the fact that the catalytic performance loss was not severe in vanadia-supported TiO2 anatase, potassium addition led to improve the catalyst lifetime. After deactivation test, potassium-containing vanadia catalyst possessed lower surface area loss (i.e. from 52 to 49 m2 g−1). Average crystallite size of potassium-containing vanadia catalyst exhibited lower decrease than that of potassium-free vanadia catalyst after deactivation test. According to Raman spectra, deactivation phenomena had influenced the population of vanadia species so that monovanadates decreased and polyvanadates increased.