负载型Pt/CeO_2-Al_2O_3催化剂的制备及其脱氢性能

Preparation of supported Pt/CeO_2-Al_2O_3 catalyst and its performance in the dehydrogenation of methylcyclohexane

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%。

Composite CeO_2-Al_2O_3 oxides with high surface area,large pore volume and large pore diameter were prepared by ultrasonic co-precipitation; with CeO_2-Al_2O_3 as the support,Pt / CeO_2-Al_2O_3 catalysts were obtained by impregnation method.The supporter and the as-prepared Pt / CeO_2-Al_2O_3 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 / CeO_2-Al_2O_3 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.