Preparation Of Catalyst Of Pt On CeO₂-Al₂O₃ Composite Supporter And Its Performance For The Dehydrogenation Of Methylcyclohexane

Hydrogen energy is an important renewable resources,it can effectively solve the problems of energy shortage and environmental deterioration.Compared with fossil fuels,hydrogen combustion does not produce nitrgen,sulfur compounds,so it will not bring pollution to the environment.Organic liquid hydride is one of the key problems to realize the industrial application of the hydrogen storage medium with high hydrogen storage capacity,safe and convenient hydrogen storage medium and the development of low temperature and high efficient dehydrogenation catalyst.Literature most of the dehydrogenation catalyst are mainly poor low temperature activity,heat stable and easy coking,dehydrogenation rate relative disadvantages of lower,so that dehydrogenation catalyst at low temperature to maintain high activity and improve the dehydrogenation rate is the main direction of research on organic hydride dehydrogenation.At present a large number of domestic and foreign literature records,noble metal catalysts especially platinum based catalysts with high activity under low temperature,low power consumption and other characteristics.Load type precious metal catalyst mainly with carbon dioxide,activated carbon and other single carrier,and of the composite carrier supported platinum for dehydrogenation of research.The Pt catalyst supported on a high specific surface area, large pore volume and pore diameter of CeO₂-Al₂O₃ composite supporter was successfully prepared by impregnation method combined with ultrasonic dispersion. The supporter and the as-prepared catalyst were characterized by XRD, NH3-TPD, BET,TEM and SEM.The dehydrogenation performance of the Pt/CeO₂-Al₂O₃ catalyst was evaluated in a micro tube-reactor by using methylcyclohexane as the model dehydrogenation compounds. The influences of the ratio of Ce/Al in the supporter, the reaction temperature and the feed rate of the reactant on the reaction conversion, the selectivity and the hydrogen-releasing ability of the catalyst were investigated. The results showed that, at the temperature of 450? and the Ce/Al mole ratio of 0.5, the catalyst showed a higher activity in the dehydrogenation of methylcyclohexane with the total conversion of 88.53% and the toluene selectivity of 94.63%.