Perovskite-type Natural Gas Catalytic Combustion Catalyst And Heat Resistance

Several candidate catalysts were selected from reported articles and then were prepared by pyrolytic decomposition of citric acid. The catalysts were calcined at 850℃ for three hours. Through catalytic activity evaluation, it was found that La0.6Ba0.4Co0.2Fe0.8O3 was very excellent at activity. So La0.6Ba0.4Co0.2Fe0.8O3 was regarded as the target catalyst. After Co was substituted by Ni, La0.6Ba0.4Ni0.2Fe0.8O3 were obtained as comparison. A series of catalysts of different La:Ba ratio and different Co:Fe ratio were prepared on the base of La0.6Ba0.4Co0.2Fe0.8O3. Another series of catalysts of different La.Ba ratio and different Ni:Fe ratio were prepared by comparison also. After calcined at 1200℃ for two hours, the measurement of activity were performed and the results were taken into account as data analysis of thermal stability evaluation. X-ray diffraction(XRD) scanning electron cicroscopy(SEM) Brunauer-Emmett-Teller (BET) nitrogen sorption. X-ray photoelectron spectroscopy (XPS) temperature programmed desorption of oxygen(O2-TPD) were used to characterize the catalysts. The effect of calcination temperature on preparation of catalysts was investigated. It was found that the catalytic activity were related to A-sitecation and B-sitecation. Optimal ratio was summarized though the test. It can be observed deactivation in catalytic activity of the samples calcined at 1200℃, which was thought to be related to the decrease of specific area and the surface oxygen species, especially to the decrease of crystal oxygen.From the examination of XRD, no significant crystal structure changes in the complex compound could be detected. From the examination of XPS and O2-TPD, the crystal oxygen which was thought to be related to the high temperature combustion activity was affected by B-site substitution, and the oxygen adsorbed which was thought to be related to the low temperature combustion activity was affected by A-site substitution. According to the results of the study, suggestions were given to improve the properties of perovskite-type composite oxide catalysts for catalytic combustion of methane.