| With the advancement and development of society,the demand for fossil fuels has increased rapidly,and this non-renewable energy is gradually drying up.Hydrogen energy is considered to be the most ideal green alternative energy source due to its many advantages such as recycling,wide source,clean and pollution-free.Therefore,the development of hydrogen energy is very important for solving the potential crisis of energy.The use of liquid organic hydride hydrogen storage can solve the problem of hydrogen energy transportation and storage.However,the dehydrogenation reaction is an endothermic reaction which easily generates by-products during the reaction,and carbon deposition occurs during dehydrogenation to cause catalyst deactivation.Therefore,the use of a simple process to prepare a low-cost catalyst,while the catalyst has high conversion,high stability,recycling,etc.,is the key to the industrial application of organic liquid hydride hydrogen storage technology.Zr-Mg-Al hydrotalcite carrier was prepared by co-precipitation method at constant pH.This carrier has excellent carbon deposition resistance because it does not contain acidic sites,and its unique layered structure is beneficial to the active group in the catalyst.The dispersion of points.Pt-Fe bimetallic catalyst was prepared by loading Pt and Fe on Zr-Mg-Al hydrotalcite carrier by load impregnation method and then calcining and reducing.Pt-Ce-Mg-Al tetrametallic hydrotalcite was prepared by co-precipitation method during the preparation of the catalyst.The active ingredient was directly added to the hydrotalcite.After filtration,calcination and reduction,Pt/Ce-Mg-Al-O catalyst was obtained.A series of characterization tests were carried out on the Pt-Fe and Pt/Ce-Mg-Al-O catalysts prepared in this study,and the results were analyzed based on the characterization results.Dehydrogenation of methylcyclohexane was carried out on a microreactor to test the dehydrogenation performance of the catalyst.The effects of different Fe content,Ce content,Pt content,reduction temperature and reaction temperature on the hydrogen release rate and stability of methylcyclohexane were investigated.The results show that the addition of Fe promotes the reduction of Pt and increases the dispersion of Pt,which reduces the average particle size of Pt.Using a one-step Pt/Ce-Mg-Al-O catalyst,the presence of a suitable amount of CeO2 can immobilize the Pt particles,which has a smaller Pt particle size and is less prone to agglomeration,and has a higher desorption in the dehydrogenation reaction.Hydrogen activity.Both catalysts exhibit excellent carbon deposition resistance and are therefore highly stable.Since the dehydrogenation reaction is an endothermic reaction,the conversion of methylcyclohexane gradually increases as the reaction temperature increases.When the feed rate is 0.1 mL/min,the reaction temperature is 350℃,the catalyst mass is 0.5 g,and the mass space velocity is 9.48 h-1,the conversion of MCH of Pt-Fe-1.6-350 catalyst is 92.6%.The hydrogen rate was 1117.5 mmol/gPt/min,the toluene selectivity was 99.9%,and there was no tendency to decrease within 16 h.The Pt/Cei4-Mg-Al-O catalyst had a methylcyclohexane conversion of 98.5%,a hydrogen evolution rate of 1358.6 mmol/gPt/min,and a toluene selectivity of 99.9%. |
