Search

La-deficient La1-xCexMnO3 mixed oxides, obtained by selective dissolution in 1 ​M nitric acid, were employed in methane complete oxidation. The majority of the La cations in these perovskites were removed, resulting in increased specific surface areas, better reducibility and greater activity. Incorporation of a small amount of Ce stabilized the structure and a perovskite phase persisted in La-deficient La1-xCexMnO3 mixed oxides after 12 ​h of acid dissolution. La0.95Ce0.05MnO3 after the acid treatment exhibited satisfactory catalytic activity, with T50 and T90 values of 365 and 459 ​°C, respectively, which was even comparable to that previously reported 1% Pd/Al2O3 catalysts. And it showed excellent long-term activity even in the presence of CO2 and H2O.

Porous ceria nanorods modified with Fe or Co were prepared via a hydrothermal method. The structural properties, catalytic activities for the total oxidation of propane, and catalytic mechanisms of these materials were systematically investigated by X-ray diffraction, Raman spectroscopy, N2 adsorption–desorption, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, catalytic activity measurements and in situ Fourier transform infrared spectroscopy. Co-modified ceria exhibited the best catalytic activity during propane oxidation as well as enhanced reducibility due to the synergistic interactions between the Co and the CeO2 support. Variations in the activating ability and reducibility of the catalysts resulted in the formation of distinctive intermediates during the catalytic process, and this explained the observed differences in catalytic performance.