Noble metal (Pd, Pt and Rh) incorporated LaFeO3 perovskite oxides for catalytic oxidative cracking of n-propane

Abstract

Noble metals (Pd, Pt and Rh) incorporated LaFeO3 (LaFe) perovskite oxide nanostructures were synthesized by adapting hydrothermal synthesis method. The synthesized materials were used as catalysts for production of olefins via oxidative cracking of n-propane. The bare LaFe sample exhibited n-propane conversion of 18% with 42% olefins selectivity at reaction temperature of 600 °C. Substantial increase in n-propane conversion and olefins selectivity was perceived after incorporation of Pd, Pt and Rh in LaFe framework. The LaFe sample incorporated with Rh exhibited superior oxidative cracking performance (85% conversion of n-propane and 79% olefins selectivity) at optimized reaction conditions. A thorough characterization of synthesized catalysts was performed using various characterization techniques to obtain a correlation between the structural properties of Pd, Pt and Rh incorporated LaFe perovskite nanostructures and their catalytic activity in olefin production. The characterization results indicated that Rh and Pt species were expelled from the bulk LaFe framework and dispersed over the surface, while Pd species were strongly interacted with LaFe and occluded inside the LaFe framework. It appears that presence of expelled Rh and Pt species on the LaFe surface are responsible for better redox properties of LaFeRh and LaFePt samples. The highest oxidative catalytic cracking activity of LaFeRh sample is due to presence of high surface area, easily reducible and great number of adsorbed oxygen moieties. Catalyst durability test results indicated that Rh incorporated LaFe sample possessed stable oxidative cracking activity for 72 h without considerable loss in performance