Y2O3 modified Au-La2O3 nanorod catalysts for oxidative cracking of n-propane

Abstract

La2O3 and 0.2Au-La2O3 nanorod samples were synthesized by hydrothermal and chemical reduction routes respectively. The synthesized 0.2Au-La2O3 nanomaterial was modified with 1, 3, 5 and 7 wt% of Y2O3 by impregnation method. Powder XRD, FT-IR spectroscopy, FE-SEM, N2-physisorption, XPS, H2-TPR and O2-TPD techniques were utilized to evaluate the physico-chemical characteristics of the synthesized materials The XRD, SEM analyses revealed that the synthesized samples possessed small crystallite sizes with rod and spherical type morphologies. The XPS analysis indicating that the gold metal particles are well dispersed on the surface of the La2O3 nanorods. The efficacy of Y2O3 supported 0.2Au-La2O3 samples for catalytic oxidative cracking of n-propane was also studied. It was observed that Y2O3 loading had an impact on the n-propane conversion and olefins selectivity. Highest activity (78% n-propane conversion, 72% olefins selectivity) was observed in case of 5Y-0.2Au-La2O3 sample at 600 °C. The H2-TPR, O2-TPD and acidity analyses results revealed that 5Y-0.2Au-La2O3 sample is easily reducible, possessed more number of Lewis acid sites and mobile oxygen species. Therefore, the combination of these characteristics are responsible for the superior activity of 5Y-0.2Au-La2O3 catalyst. In addition, the synthesized catalysts showed stable catalytic n-propane oxidative cracking activity for 24 h without considerable deactivation.