通过原位合成的方式,成功将Sc原子引入ZSM-5催化剂的骨架中,且制备的Sc改性ZSM-5沸石分子与ZSM-5的拓扑结构(MFI型)相同.通过X线衍射(XRD)谱图及扫描电镜(SEM)可以发现,Sc-ZSM-5的晶体结构未发生明显变化,未发现共生相.根据SEM及N2吸脱附测试可以发现,其小晶粒堆积的形貌结构形成了明显的微介孔复合多级孔结构.通过X线光电子能谱(XPS)、能量色散X谱(EDS)、电感耦合等离子体原子发射谱仪(ICP-AES)等手段对其进行表征,发现Sc原子成功地进入ZSM-5催化剂的骨架中.将离子交换后的H型Sc-ZSM-5分子筛用于甲醇制烯烃(MTO)的反应,并与传统的ZSM-5分子筛反应结果进行比较.Sc-ZSM-5因具有更加开放的孔道结构,表现出略高于传统ZSM-5的催化寿命.此外,Sc改性分子筛中的Sc通过调节ZSM-5的酸度以及Al的空间和骨架分布显著提高了丙烯以及低碳烯烃的选择性.
Scandium(Sc)was successfully incorporated into the framework of ZSM-5 catalysts via an in-situ synthesis method,maintaining the original MFI-type topological structure of ZSM-5 zeolites.X-ray diffraction(XRD)analysis and scanning electron microscopy(SEM)of Sc-ZSM-5 revealed no significant changes in crystal structure,with no coexisting phases detected.SEM and nitrogen adsorption-desorption assays demonstrated that the accumulation of small crystals led to the formation of a pronounced micro-mesoporous composite hierarchical pore structure.Characterization utilizing X-ray photoelectron spectroscopy(XPS),energy-dispersive X-ray spectroscopy(EDS),and inductively coupled plasma atomic emission spectroscopy(ICP-AES)confirmed the successful integration of Sc atoms into the ZSM-5 catalyst framework.The ion-exchanged H-form Sc-ZSM-5 zeolite was employed in the methanol-to-olefins(MTO)reaction and compared with conventional ZSM-5 zeolites.Sc-ZSM-5 exhibited a marginally enhanced catalytic lifetime due to its more open pore structure.Furthermore,the introduction of Sc into the modified zeolite significantly improved the selectivity towards propylene and lower olefins by modulating the acidity and the spatial distribution of Al within the ZSM-5 framework.
马奔;邓敦彬;吴梦菲;陈立宇;曲云龙;陆琨
上海理工大学材料与化学学院,上海 200093
化学工程
ZSM-5分子筛;Sc改性分子筛;多级孔结构;甲醇制烯烃;低碳烯烃
ZSM-5 zeolite;scandium modified zeolite;multistage pore structure;methanol to olefin;low-carbon alkenes
《南京工业大学学报（自然科学版）》 2024 (002)
149-159 / 11
国家自然科学基金(22202132)
10.3969/j.issn.1671-7627.2024.02.004
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