Study on Methane Catalytic Combustion of Mn Doped LaMn_xAl_(12-x)O_(19+σ) Hexaaluminate Catalysts
Cui Meisheng, Zhang Shunli, Li Minglai, Long Zhiqi, Huang Xiaowei (General Research Institute for Non-Ferrous Metals, Grirem Advanced Materials Co.,Ltd, Beijing 100088, China)
Series of hexaaluminates LaMn_xAl_(12-x)O_(19+σ) doped with Mn (Here x is 0, 0.5, 1.0, 1.5, 2.0, 5.0 respectively) were synthesized by co-precipitation method, and the physico-chemical properties were characterized by means of BET, TG-DTA, and XRD techniques. Effect of Mn doped content on methane combustion catalytic activity was also studied. It shows that catalytic activity of LaAl_(12)O_(19+σ) is low, catalyst activity is enhanced gradually with the introduction of Mn, and when doped Mn content reached 1.5, namely x=1.5, the activity is up to peak. The crystal phase and activity are greatly affected by cacination temperature, and full hexaaluminates with good activity were formed when catalysts cacinated at 1200 ℃ for 4 h. The best performances of the samples are that light-off T_(10%) is 418 ℃, and conversion T_(90%) is 663 ℃.