Yttrium Oxide Supported La2O3 Nanomaterials for Catalytic Oxidative Cracking of n-Propane to Olefins

Abstract

La2O3 nanorods were prepared by simple hydrothermal synthesis method. Yttrium oxide (1, 3, 5 and 7 wt%) supported La2O3 and SO42− incorporated La2O3 nanorods were prepared impregnation method and used as catalysts in oxidative cracking of n-propane. The pure La2O3 nanorods exhibited 15% n-propane conversion with 22% olefins (ethane and propene) selectivity. Considerable improvement in n-propane conversion was observed in case of 3 wt% yttrium oxide supported on La2O3 nanorods (25% conversion of n-propane and 36% selectivity to olefins) at reaction temperature of 550 °C. Interestingly, 5 wt% yttrium oxide supported 10 wt% SO42−/La2O3 nanorod sample exhibited superior performance in n-propane conversion (42%) and olefins selectivity (54%). The yttrium oxide loading and sulfation of La2O3 nanorods influenced the catalytic activity. The characterization of synthesized nanomaterials was performed using elemental analysis, XRD, FT-IR, N2-physisorption, SEM, XPS and H2-TPR techniques. The obtained results indicated that yttrium oxide was highly dispersed over the La2O3 nanorods because of strong interaction between the two rare earth metal oxides. Additionally, deposition of yttrium oxide to sulfated La2O3 nanorods increased the surface area and the amount of Lewis acid sites (for the activation of n-propane) on La2O3 nanorods. Yttrium oxide supported sulfated La2O3 catalyst showed no deactivation during the 24 h of reaction and without coke formation.