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通过改变煅烧温度、煅烧时间和前驱体溶液pH值,在不同条件下用溶胶凝胶法制备了LaMnO3钙钛矿型催化剂。使用BET、XRD等实验手段对催化剂进行了表征测试,利用热重分析仪对催化剂催化氧化碳黑的活性开展了程序升温氧化实验研究,并用Coats-Redfern方法进行了反应动力学分析。实验结果表明,煅烧温度对LaMnO3钙钛矿催化剂的形成起到关键作用,973K煅烧的催化剂可以获得最大的反应活性;煅烧时间对钙钛矿的形成也有一定影响,煅烧超过6h的催化剂活性较高;前驱体溶液pH值呈碱性时,可以获得最大的催化剂表面积以及表面活性位密度,从而提高催化剂的整体活性。
The LaMnO3 perovskite catalyst was prepared by sol-gel method under different conditions by changing the calcination temperature, calcination time and the pH value of the precursor solution. The catalysts were characterized by BET, XRD and other means. The thermal oxidation of the catalyst was investigated by TG-CTA. The kinetics of the reaction was investigated by Coats-Redfern method. The experimental results show that the calcination temperature plays a key role in the formation of LaMnO3 perovskite catalyst, and the 973K calcined catalyst can obtain the maximum reactivity. The calcination time also has a certain influence on the formation of perovskite. The calcined catalyst activity is higher than 6h ; When the pH value of the precursor solution is alkaline, the maximum catalyst surface area and the surface active density can be obtained, thereby improving the overall activity of the catalyst.