Preparation and characterization of La0.8Cu0.2MnO(3±δ) perovskite-type catalyst for methane combustion

La0.8Cu0.2 MnO(3+/-delta) perovskite-type catalyst for methane combustion prepared through sol-gel process was characterized by X-ray Diffractometry(XRD), X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy(SEM). XPS analyses reveal that the surface characteristics of the catalyst are changed. The lattice defects and oxygen vacancies on the catalyst surface are enhanced due to a part of La3+ being substituted by Cu2+. Temperature-programmed-desorption (TPD) and temperature-programmed-reduction (TPR) analyses were carried out to study the catalytic behavior. It is found that there are two O-2-desorption peaks at 350 degrees C and 650 degrees C in the TPD pattern, and two CH,-consumption peaks at 420 degrees C and 750 degrees C in the TPR patterns respectively, which indicates that the two kinds of oxygen species, so-called alpha and beta oxygen, can react with the methane during catalytic combustion process. The catalytic activity tests were performed in a fixed-bed reactor, and the results show that the T-1/2 at which the conversion of methane attains 50% of La-0.8 Cu-0.2 MnO(3+/-delta) is lower by 55 degrees C than that of LaMnO3 This indicates that the catalytic activity of La-0.8 Cu-0.2 MnO(3+/-delta) is increased with partial substitution Of Cu2+ for La3+.