Abstract MOR zeolite has been extensively employed as a catalyst in industries. However, high Bronsted acidity in MOR leads to rapid deactivation due to coke deposition on the pore mouths; thus, the surface acidity of MOR needs to be moderated. Herein, we report a modification of MOR chemical composition via acid treatment and deposition of ceria nanoparticles using a wet impregnation method. The acid treatment successfully increases the Si/Al ratio of MOR from 8.39 to 11.58 and reduces the total acid site concentration of MOR from 990 μmol/g to 752 μmol/g. The acidity of MOR is decreased when the Si/Al ratio is increased since the quantity of Bronsted acid sites is proportional to the number of Al framework. In addition, the acid treatment also improves the external surface area of MOR. Furthermore, ceria particles were successfully deposited on the MOR surface using wet impregnation method. The ceria content of parent MOR sample is lower compared to that of preceded by the acid treatment, which may be attributed to the formation of more terminal silanol groups. Finally, catalytic test on Friedel–Crafts alkylation of toluene with benzyl alcohol shows that the synergy between dealumination and the impregnation of ceria significantly improves the activity of MOR zeolite.

中文翻译：

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脱铝和氧化铈浸渍对MOR沸石催化性能的协同作用

摘要 MOR 沸石在工业中被广泛用作催化剂。然而，由于焦炭沉积在孔口，MOR 中的高布朗斯台德酸度导致快速失活；因此，需要调节 MOR 的表面酸度。在此，我们报告了使用湿浸渍法通过酸处理和二氧化铈纳米颗粒沉积来改变 MOR 化学成分的方法。酸处理成功地将 MOR 的 Si/Al 比从 8.39 提高到 11.58，并将 MOR 的总酸位浓度从 990 μmol/g 降低到 752 μmol/g。由于布朗斯台德酸位的数量与铝骨架的数量成正比，当 Si/Al 比增加时，MOR 的酸度降低。此外，酸处理还提高了 MOR 的外表面积。此外，使用湿浸渍法成功地将氧化铈颗粒沉积在 MOR 表面。母体 MOR 样品的二氧化铈含量低于酸处理前的含量，这可能是由于形成了更多的末端硅烷醇基团。最后，甲苯与苯甲醇的 Friedel-Crafts 烷基化反应的催化试验表明，脱铝和氧化铈浸渍之间的协同作用显着提高了 MOR 沸石的活性。