Designed Synthesis and Crystallization of Fe-Al-EU-1 Zeolites Containing Framework-Iron

	Designed Synthesis and Crystallization of Fe-Al-EU-1 Zeolites Containing Framework-Iron
	Yang, DH; Zhao, JF; Zhang, JL; Dou, T; Wu, ZH; Chen, ZJ;吴忠华; Chen ZJ(陈中军)
刊名	ACTA PHYSICO-CHIMICA SINICA
	2012
卷号	28 期号:3 页码:720-728
关键词	Fe-Al-EU-1 zeolite Bonding state Crystallization X-ray absorption fine structure Physical and chemical property Characterization
英文摘要	Highly crystalline Fe-Al-EU-1 zeolites were hydrothermally synthesized in a HMBr2-Na2O-Al2O3-SiO2-Fe2O3-H2O system by using hexamethonium bromide (HMBr2) as a template. The physical and chemical properties, and the bonding state of Fe in the zeolite framework for the prepared Fe-Al-EU-1 samples were characterized by a series of techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric-derivative thermogravimetric (TG-DTG) analysis, N-2 adsorption-desorption, solid-state nuclear magnetic resonance (NMR), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), and X-ray absorption fine structure (XAFS). The results show that with increasing the mass fraction of Fe in the original sol-gel, the unit cell volume of Fe-Al-EU-1 zeolite inflates; the zeolite doped with Fe causes an increase in its surface area (BET) from 272 to 365 m(2) . g(-1) and a reduced amount of template removal, as well as a decrease in decomposition temperature. Adding Fe ions into sol-gel also leads to lowered zeta potential, easily gathered colloidal particles, and increased shape of zeolite. The UV-Vis spectrum shows that there is a characteristic peak at about 220-250 nm with a sharply increased intensity due to the p-d transition of the bonding electrons from the 2p-orbital of 0 atom to the d-orbital of the four-coordinated Fe atom in the framework. Also at around 373 nm, the coordination bonding of four-coordinated Fe atoms and adjacent Si - O groups leads to a d-d charge transition peak with an energy level splitting and increased peak intensity. The XAFS results show that with the crystallization process going on, the pre-edge absorption peak for 1s -> 3d and main absorption peak for 1s -> 4p change significantly. Four-coordinated structural units of iron species formed from the original sol-gel samples are gradually transformed into a tetrahedral coordinated iron-silicon-oxygen skeleton, in which iron-silicon-oxygen ionic structural unit is also transformed into skeleton iron species with a tetrahedral covalent bonding structure.
学科主题	Chemistry
收录类别	SCI
WOS记录号	WOS:000301693800034
公开日期	2016-05-03
内容类型	期刊论文
源URL	[http://ir.ihep.ac.cn/handle/311005/224049]
专题	高能物理研究所_多学科研究中心
推荐引用方式 GB/T 7714	Yang, DH,Zhao, JF,Zhang, JL,et al. Designed Synthesis and Crystallization of Fe-Al-EU-1 Zeolites Containing Framework-Iron[J]. ACTA PHYSICO-CHIMICA SINICA,2012,28(3):720-728.
APA	Yang, DH.,Zhao, JF.,Zhang, JL.,Dou, T.,Wu, ZH.,...&陈中军.(2012).Designed Synthesis and Crystallization of Fe-Al-EU-1 Zeolites Containing Framework-Iron.ACTA PHYSICO-CHIMICA SINICA,28(3),720-728.
MLA	Yang, DH,et al."Designed Synthesis and Crystallization of Fe-Al-EU-1 Zeolites Containing Framework-Iron".ACTA PHYSICO-CHIMICA SINICA 28.3(2012):720-728.