MoO_3负载质量分数对MoO_x/Al_2O_3丙烷氧化脱氢反应性能的影响

Influence of MoO_3 loading on oxidative dehydrogenation of propane on MoO_x/Al_2O_3 catalyst

以Al2O3为载体,钼酸铵为前驱体,采用浸渍法制备了丙烷氧化脱氢制丙烯MoOx/Al2O3催化剂。借助X射线衍射仪、傅里叶变换红外光谱仪及多功能程序升温分析仪对催化剂性质及反应性能进行了评价。结果表明,当MoO3负载质量分数低于13%时,钼物种分散性较好;高于13%时,在催化剂表面出现Al2(MoO4)3晶相;继续增加到27%时,出现MoO3晶相。当MoO3负载质量分数为18%时,MoOx/Al2O3催化剂的活性及选择性最佳,酸量最高(0.412 mmol/g),丙烷转化率与丙烯收率分别为22.18%,14.01%。

MoOx/Al2O3 catalysts for oxidative de- hydrogenation of propane were prepared by the in- cipient wetness impregnation method using Al2O3 as support and （ NH4 ）6Mo7O24· 4H2O as precursor. The catalysts were obtained and their catalytic be- havior were characterized by X - ray diffractometer, Fourier transform infrared spectrometer and multi - functional temperature programmed analyzer. The re- sults showed that the molybdenum species were welldispersed on the support at their loading less than 13%. Al2 （MOO4）3 and MoO3 crystals appeared when the loading increased to no less than 13% and 27% respectively. At the optimum MoO3 loading （18%）, the propane conversion and the propene yield were 22. 18% , 14.01% respectively and the acid amount reached its maximum （0. 412 mmol/g）.