负载型Pt/CeO_2-Al_2O_3催化剂的制备及其脱氢性能

通过超声辅助共沉淀法制备了具有高比表面积、大孔容和大孔径的CeO_2-Al_2O_3复合载体,并以此制备了一系列负载型Pt/CeO_2-Al_2O_3催化剂,采用XRD、氮吸附、NH3-TPD、SEM和TEM等方法对复合载体和催化剂进行了表征;以甲基环己烷为模型化合物,考察了Pt/CeO_2-Al_2O_3催化剂的脱氢性能,研究了载体中Ce/Al物质的量比及反应温度对其催化脱氢性能的影响。结果表明,当Ce/Al物质的量比为0.5时,Pt/CeO_2-Al_2O_3催化剂在450℃下具有较高的脱氢性能;甲基环己烷转化率达到88.53%,甲苯的选择性达94.63%。

Preparation of supported Pt/CeO2-Al2O3 catalyst and its performance in the dehydrogenation of methylcyclohexane

Composite CeO₂-Al₂O₃ oxides with high surface area, large pore volume and large pore diameter were prepared by ultrasonic co-precipitation;with CeO₂-Al₂O₃ as the support, Pt/CeO₂-Al₂O₃ catalysts were obtained by impregnation method. The supporter and the as-prepared Pt/CeO₂-Al₂O₃ catalysts were characterized by XRD, NH₃-TPD, nitrogen sorption and SEM;their catalytic performance in the dehydrogenation of methylcyclohexane as a model compound was investigated in a micro tube-reactor and the influences of Ce/Al (mol ratio) and reaction temperature on the dehydrogenation activity were considered. The results indicate that the Pt/CeO₂-Al₂O₃ catalyst with a Ce/Al (mol ratio) of 0.5 performs best at 450℃ in the dehydrogenation of methylcyclohexane, with a methylcyclohexane conversion of 88.53% and a selectivity of 94.63% to toluene.