Study on Preparation and Catalytic Performance of Supported Catalysts for Low-Temperature CO Oxidation
|School||Beijing University of Chemical Technology|
|Course||Chemical Engineering and Technology|
|Keywords||CO oxidation Co3O4/SiO2 CuO/CeO2 Glycol High dispersibility|
Flurry CO catalytic oxidation has important practical value in many ways, as used in underground mines the filter self and the fire self-help respirator, CO gas sensors, the closed CO2 lasers as well as the closed system within the CO elimination aspects. Meanwhile, due to the reaction system, the theoretical study of CO oxidation is also often used as a probe reaction to study the oxidation catalyst, in order to reveal the relationship between the structure and properties of the catalyst, and to explore the reaction mechanism. Although the noble metal catalyst, with its high activity is considered is CO The preferred catalyst of the low-temperature oxidation, but expensive due to its cost, poor stability, the preparation process cumbersome and other shortcomings, research and development price low, with the noble metal catalyst activity comparable to the non-noble metal catalyst gradually become a hot research field of catalysis. This article as a starting point, prepared Co3O4/SiO2 and CuO/CeO2 two kinds of non-precious metal catalyst, CO oxidation performance of research and catalysts were characterized by means of BET, XRD, TEM, XPS analysis, examine its catalytic properties and structure of the relationship. Experiment SiO2 as carrier impregnation prepared the high dispersion Co3O4/SiO2 catalyst. The pretreatment of the catalyst carrier, changing the surface chemical properties of the carrier of SiO2, and enhance the interaction between the metal oxide and the carrier, thereby improving the activity of the catalyst by using a simple organic solvent glycol. According to the results of XRD and TEM, supported on the particle diameter after the pretreated carrier CO3O4 significantly reduced, improved dispersibility, Co3O4 particle size is also changed with the glycol different dosage. When the glycol volume fraction of 10 vol%, compared to the particle diameter of Co3O4 load has not been pretreated carrier Co3O4 and the particle size is reduced by about 4 times, complete conversion to CO2 in the temperature to reduce the CO 140 K. On the other hand, we valence state of the catalyst surface Co elements with content by means of XPS test for the qualitative and quantitative analysis. The results showed that the catalyst prepared from 10 vol% ethylene glycol pretreatment carrier, its surface Co3 ion content is increased significantly, from 47% to 63%. While Co3 cobalt oxide catalyst on the activity of the CO oxidation reaction, which means that the carrier increased catalyst activity after ethylene glycol treatment points, the CO oxidation reaction activity increased. Urea as precipitating agent, using homogeneous precipitation prepared CuO/CeO2 process, we use ethylene glycol instead of water as a solvent, reducing the particle size of the precipitated particles, CO conversion rate of 100% of the temperature 40 K lower , catalyst activity increased. In addition, the experimental use of hexamethylene tetramine heating hydrolysis strong ammonia, and hydrogen peroxide oxidation, low-temperature preparation of copper-cerium catalyst. The influence of the heating conditions during the preparation and calcination temperature on catalyst activity were investigated, the results showed that the reaction was heated at 50 ℃ 6h after which the solid substance obtained is filtered in the 200 ° C calcination prepared CuO/CeO2 highest catalyst activity.