Catalytic combustion of methane on La1-xCexFeO3 oxides

A series of La1-xCexFeO3 (x = 0-0.5) perovskite oxides were prepared by a sol-gel method. X-ray diffraction spectrometer (XRD), BET surface area measurements, scanning electron microscopy (SEM) images, and temperature-programmed reduction (TPR) were used to characterize their physical structures and redox properties. Catalytic methane combustion tests for La1-xCexFeO3 (x = 0-0.5) perovskite oxides show that the activity of LaFeO3 was highly improved due to the introduction of Ce in the A-site of the perovskite catalysts. Among all the catalysts, La0.7Ce0.3FeO3 has the maximum oxidative performance with the corresponding T-90 as low as 510 degrees C. Combining with density functional theory calculation, it was suggested that the electrons of Fe ions increase in La0.875Ce0.125FeO3 due to the introduction of Ce4+ ion, which leads to stronger interactions with adsorbed O-2. Correspondingly, the adsorption energy of O-2 on La0.875Ce0.125FeO3 increases and the O-O bond is activated. Thus, the Ce doped perovskite has higher oxidative activity than pure LaFeO3. (C) 2013 Elsevier B.V. All rights reserved.