Design And Performance Of Novel V-based Catalysts For Oxidative Dehydrogenation Of Propane With CO₂

Propylene is the main raw material for the production of enormous chemical products such as propylene oxide,acetone,acrylonitrile,acrolein,and polypropylene,moreover,it is one of the footstones of modern chemical industry.Traditional propylene production processes include fluid catalytic cracking,steam cracking of naphtha and light diesel oil,etc.Nevertheless,with the rapid consumption of fossil energy and the increasing demand for propylene,traditional propylene production processes cannot meet the raising demand for propylene.The new high-efficiency propylene production technology is of great significance.Oxidative dehydrogenation of propane with CO₂technology can use relatively large and underutilized propane to produce propylene,and it provides a new solution to the consumption and utilization of the greenhouse gas CO₂.It is a very potential technology for propane dehydrogenation to propylene.In this paper,by exploring the role of different new vanadium-based catalysts in the oxidative dehydrogenation of propane with CO₂,the structure-activity relationship between the concentration of vanadium species on the surface of the vanadium-based catalyst and the activity of propane dehydrogenation is established.It was found that the aggregation state of vanadium species on the surface can be controlled by adjusting the loading of vanadium,more highly polymerized poly-vanadate can be obtained without generating V₂O₅microcrystals.If the surface vanadium loading is appropriate,a uniform poly-vanadate monomolecular layer can be formed on the surface of the catalyst carrier.The highly polymerized poly-vanadate has suitable acidity,can increase the proportion of V⁴⁺in the vanadium species,and produces less carbon deposits in the catalytic reaction of propane dehydrogenation,which all help to improve the propane dehydrogenation of vanadium-based catalysts,these catalysts can achieve a maximum of 58%propane conversion and 84%propylene selectivity.Reactivity.Then,through the combination of a Cu and Zn based catalyst with reverse water vapor shift reaction activity and a propane direct dehydrogenation catalyst,the synergy and coupling enhancement between the propane direct dehydrogenation catalyst and the reverse water vapor shift catalyst are realized,which is the vanadium-based catalyst for the oxidation of propane CO₂.The directional optimization method in the hydrogen reaction provides theoretical guidance.In addition,through the design and optimization of the preparation conditions of the new Mo₃VO_xframework material and the modification of the Mo₃VO_x framework materials,this paper found that the doping of elements such as cobalt and cerium can improve the selectivity of propylene in the propane CO₂ oxidative dehydrogenation reaction of the Mo₃VO_x framework material.The properties and thermal stability of the catalyst provide theoretical guidance for the preparation and optimization of Mo₃VOx framework materials and other polyoxometalate framework materials.