The Preparation Of Three-dimensionally Ordered Macroporous Catalysts For Oxidative Dehydrogenation Of Propane

The oxidative dehydrogenation of low value propane to propene has been a very interesting research project for industrial application and theoretical research value.Ni-Ce-O catalysts is regarded as a kind of very potential catalyst due to their low temperature moderate catalytic reaction with high propene selectivity,but propane conversion are not high.It is well known that the propane conversion increase but propylene selectivity decrease with the rise of temperatures.So we mean to improve the spread of the catalyst performance to inhibit secondary oxidation of propene to obtain more propene.In recent years,three-dimensional ordered macroporous?3DOM?materials caused wide concern in catalytic applications.3DOM materials have high specific surface area,uniform and orderly through channel structure and unique catalytic performance which attracted the attention of the researchers.Therefore,this thesis prepares a series of catalysts with three-dimensional ordered macroporous structure,through modulation of its composition,phase structure and so on to study the structure-activity relationship on the catalyst;the research content and the getting conclusion summed up as follows:?1?Preparing successfully 3DOM VMgO catalysts by hard template method for oxidative dehydrogenation of propane at high temperature.Vanadium content has great influence on the physical and chemical properties of catalyst and catalytic reaction performance.The results show that the propane conversion has a positive correlation with the content of isolated tetrahedron VO₄ species.In addition,compared with other catalysts,V content present the best propylene yield?11.3%?at 3DOM 32VMgO catalyst.?2?3DOM NiCe catalyst were prepared by the colloidal crystal template method for oxidative dehydrogenation of propane at low temperature.Nickel content for the physical and chemical properties of catalyst and catalytic performance has great influence.With the increase of nickel content,more nickel modified the structure of the CeO₂,formation of reactive oxygen species and more NiOx,which were beneficial to the improvement of the propane conversion and propene selectivity.Continue to increase the content of nickel,depth of oxidation reaction,propane conversion rate increase but the sharp decline in propylene selectivity.In addition,compared with other catalysts,3DOM 2NiCe catalysts presented higher propane conversion?30.3%?and propene selectivity?39.4%?.?3?Comparing the non-template structure catalyst to 3DOM structure,the results show that the 3DOM structure has a larger specific surface area,which is advantageous to the high dispersion of active site;And orderly through pore structure can improve the diffusion ability of catalyst to increase the selectivity of propene.