【摘要】 采用海藻酸铵辅助法制备了Sn杂化Al₂O₃球形颗粒,并通过浸渍法获得Pt/Snx-Al₂O₃-X催化剂.采用氮吸附-脱附、XRD、NH3-TPD、XPS与TEM,研究了Sn杂化量与煅烧温度对催化剂孔结构、晶相、表面酸性、Sn价态、催化剂表面Pt颗粒大小的影响,并评估了催化剂在丙烷脱氢过程中的反应活性.实验结果表明,Sn的引入没有改变γ-Al₂O₃的晶相,但是可以提高催化剂的热稳定性;随着煅烧温度的提高,催化剂孔容、孔径明显增加,而比表面积与表面总酸量明显减少;Pt/Sn15-Al₂O₃-800催化剂表面Pt、Sn与γ-Al₂O₃之间相互作用较强,Sn0含量较低,同时Pt粒子平均粒径最小,其丙烷脱氢活性也最好,收率可达35%,以上.更多还原

【Abstract】 Sn-doped spherical alumina were prepared by ammonium alginate assisted sol-gel method and Pt/Snx Al₂O₃-X was obtained by impregnation method.The samples were characterized by N2 adsorption-desorption,XRD,NH3-TPD,XPS and TEM.The effects of the amount of Sn-doped and calcination temperature on the pore structure,crystal phase,surface acidity,Sn valence and Pt particle size on the catalyst surface were investigated. The property of the catalysts in the dehydrogenation of propane was evaluated.The results indicate that the introduction of Sn has no effect on the crystal phase of γ-Al₂O₃,but significantly increases the thermal stability of the catalyst. With the increase of the calcination temperature,the pore volume and the average pore size of the catalyst increase while the specific surface area and the total surface acid amount decrease obviously. The interaction among Pt,Sn and γ-Al₂O₃ is stronger on Pt/Sn15-Al₂O₃-800 catalyst surface,and the content of Sn0 is lower.At the same time,the mean particle diameter of Pt particles is the smallest,and the propane dehydrogenation activity is the best which can reach more than 35%,.更多还原