负载型超强酸催化剂ZS-SiO2的研究

研究了载体SiO2对催化剂ZS-SiO2中ZrO2结晶过程的影响，考察了催化剂ZS-SiO2的结构、酸性和比表面积以及对正己烷异构化反应的催化活性。XRD实验结果表明，SiO2对ZrO2结晶过程的影响是复杂的。未经高温焙烧的SiO2(a)与负载在其表面的ZrO2存在着较强的化学作用，延迟了ZiO2结晶；经过高温焙烧的SiO2(b)对ZiO2的晶相有较大影响，它使ZS-SiO2(b)中四面体晶相与单斜晶相组成比例明显不同于ZS。NH3-TPD结果表明，ZS-SiO2(b)与ZS有相类似的NH3脱附谱图，它们具有相同类型的酸中心，但酸量有所不同；ZS-SiO2(a)没有明显的高温NH3脱附峰。活性评价结果表明，ZS-SiO2(b)对正己烷异构化反应有催化活性，对比无SiO2载体的催化剂ZS，其催化活性明显下降，而ZS-SiO2(a)则无催化活性。

STUDY ON SUPPORTED SURPERACID CATALYST ZS-SiO2

The effects of SiO2 support on properties of ZS-SiO2 catalysts, their crystalline structure, acidity, specific surface area and catalytic activity for isomerization reaction of n-hexane were investigated. The XRD results showed that the effect of SiO2 on crystallization of ZrO2 was due to the chemical interaction between the support SiO2(a) (Uncalcinated) and crystallized ZrO2 supported on its surface. The crystallization of ZrO2 on the surface of support SiO2(a) was retarded by chemical interaction. But SiO2(b) (Calcinated at high temperature) affected crystalline structure of ZiO2.The relative amount of tetragonal versus monoclinic in the crystal phase of ZS-SiO2(b) was distinctly different from that of ZS. The results of NH3-TPD showed that the NH3 desorption profiles of ZS-SiO2(b) was analogous to that of ZS. They showed similar types of acidity, but different in acid amount. As for ZS-SiO2 (a), the NH3 desorption peaks at high temperature Were not observed. The ZS-SiO2(b) had still catalysis activity for isomerization reaction of n -hexane, which was lower than that of ZS.The ZS-SiO2(a) possessed no catalysis activity for isomerization reaction of n-hexane.