Template Preparation Of Iron-cobalt Catalysts For CO₂ Hydrogenation Catalytic Properties Of Light Olefins

CO₂ hydrogenation of olefins has important significance on saving energy, reducing global warming and environmental protection. The catalytic performance of catalyst plays an important role on improving CO₂ conversion and selectivity of light olefins, and has closely relative with pore structure, phase composition and surface acidity. In order to solve the problems of low utilization of the active ingredient and smaller surface area, Which was prepared with impregnation and sol-gel methods. In this paper, template methods were applied to prepare unsupported mesoporous Fe Co catalyst, through evaluating their performance on a fixed-bed reactor, with analyzing by SEM, N2-adsorption/desorption, XRD, CO₂-TPD and other characterizing methods,Studying the surface properties of the template, preparation of the catalysts, doped with other metals and reaction conditions on the catalytic properties.Respectively using SBA-15 and NH2-SBA-15 as the template, prepared Fe Co and NH2-Fe Co catalyst, by means of SEM, N2-adsorption/desorption, XRD, CO₂-TPD and other characterizing methods, investigating the surface properties of the template on the influence of the morphology, pore structure and phase composition. The result shows that: the Fe Co catalyst prepared with SBA-15 has better catalytic performance.Setting different dipping methods, different concentration of the precursor solution, Fe/Co ratio and calcination temperature to prepare Fe Co catalysts with SBA-15, by means of SEM, N2-adsorption/desorption, XRD, CO₂-TPD and other characterizing methods, investigating the preparation conditions on the influence of the morphology, pore structure, phase composition and acid-base properties.The results shows that, the optimal conditions were as follows: ultrasonic immersion, the precursor concentration 0.8mol/L, Fe/Co=3, calcination temperature 600 ℃. In the condition, the CO₂ conversion reaches 77.9%, olefins selectivity reaches 47.9%.Doping with different metals, setting different calcination temperature to prepare Fe Co catalysts with SBA-15, by means of SEM, N2-adsorption/desorption, XRD, CO₂-TPD and other characterizing methods,investigating different metals and calcination temperature on the influence of the morphology, pore structure, phase composition and acid-base properties. The results showed that the optimal conditions were as follows: Doped 7wt% Mg, calcination temperature 650 ℃, In the condition, the CO₂ conversion reaches 83.5%, olefins selectivity reaches 49.6%.Using 7wt.% Mg/Fe Co catalyst, through evaluating their performance on a fixed-bed reactor, Influences of reduction temperature, reaction temperature, reaction pressure and airspeed on catalytic performance have been investigated. The results shows that, CO₂ hydrogenation of olefins suitable reaction conditions are: reduction temperature 400℃, reaction temperature 350℃, reaction pressure 3Mpa, airspeed 3500h-1.