有机液相储氢载体脱氢催化剂的制备及催化性能

Preparation and catalytic performance of dehydrogenation catalyst in organic liquid phase hydrogen storage carrier

利用等体积浸渍法制备一系列不同Sn负载量的Pt-Sn/Al_(2)O_(3)催化剂以及Pt/活性炭、Pt/Al_(2)O_(3)单金属催化剂,采用X射线衍射(XRD)、高分辨透射电子显微镜(HRTEM)、氨气程序升温脱附(NH_(3)-TPD)、低温N_(2)吸附手段,对所制备的催化剂进行表征。使用固定床反应器,分别以甲基环己烷和12H-苄基甲苯为原料,对所制备的催化剂进行脱氢反应性能评价。结果表明:氧化铝载体催化剂酸量、酸强度均高于活性炭载体催化剂,但氧化铝载体Pt-Sn催化剂在负载Sn后,中强酸酸性位强度得到不同程度的减弱;对甲基环己烷-甲苯储氢体系筛选出脱氢效果最优的0.5Pt-0.2Sn/Al_(2)O_(3)催化剂(含量为质量分数,%),甲苯选择性超过99%,脱氢率高于97%;60 d长周期运行后甲基环己烷脱氢转化率超过98.5%,甲苯选择性高于99%,催化剂未出现失活现象。

A series of Pt-Sn/Al_(2)O_(3) catalysts with different Sn loadings,Pt/activated carbon and Pt/Al_(2)O_(3) monometallic catalysts were prepared by an equal volume co-impregnation process.The catalysts were characterized using X-ray diffraction(XRD),high resolution transmission electron microscopy(HRTEM),temperature-programmed desorption of ammonia(NH_(3)-TPD),and N_(2) adsorption at low temperature.The results show that the acidity and strength of the alumina supported catalyst are higher than those of the activated carbon supported catalyst,but the acidity of the Pt-Sn catalyst on the alumina supported catalyst is weakened to varying degrees after loading Sn.The 0.5Pt-0.2Sn/Al_(2)O_(3)(mass fraction,%)catalyst with the best dehydrogenation effect was selected for the methyl cyclohexane toluene hydrogen storage system.The selectivity for toluene exceeds 99%,and the dehydrogenation rate is morw than 97%.After 60 d of long-term operation,the conversion rate of methyl cyclohexane dehydrogenation exceeds 98.5%,the selectivity for toluene is higher than 99%,and the catalyst dose not show any deactivation.