Abstract
Mesoporous heteroatom molecular sieve MCM-41 bulk crystals with the crystalline phase were synthesized via a one-step hydrothermal method using an ionic complex as template. The ionic complex template was formed by interaction between cetyltrimethylammonium ions and metal complex ion [M(EDTA)]2− (M = Co or Ni)]. The materials were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, N2 adsorption-desorption isotherms, and X-ray absorption fine structure spectroscopy. The results showed that the materials possess a highly-ordered mesoporous structure with a crystalline phase and possess highly uniform ordered arrangement channels. The structure is in the vertical cross directions with a crystalline size of about 12 µm and high specific surface areas. The metal atoms were incorporated into the zeolite frameworks in the form of octahedral coordinate and have a uniform distribution in the materials. The amount of metal complexes formed by metal ion and EDTA is an essential factor for the formation of the vertical cross structure. Compared to Si-MCM-41, the samples exhibited better conversion and higher selectivity for cumene cracking.
Highlights
By virtue of their high thermal and hydrothermal stability, microporous zeolites are widely used in industries as heterogeneous catalysts, as solid acid catalysts in the fields of oil refining and petrochemistry [1]
The results show that the samples have well-defined morphologies with a crystal structure, and the crystalline sizes are about 12 μm with a uniform distribution
Mesoporous heteroatom molecular sieves MCM-41s with crystalline phase were synthesized via a one-step hydrothermal method
Summary
By virtue of their high thermal and hydrothermal stability, microporous zeolites are widely used in industries as heterogeneous catalysts, as solid acid catalysts in the fields of oil refining and petrochemistry [1]. The micropores of zeolites have often been described as having excellent potential for chemical functions, their pore size often limits the reaction rate and have an adverse effect on practical chemical processes [2,3,4]. In 1992, in an attempt to overcome this problem, Mobil Oil Corporation synthesized a family of mesoporous solids named M41s [5] which possess an ordered arrangement of larger pores with diameters of 2–10 nm. The use of these materials as catalysts is hampered by their relatively low thermal stability and weak acid strength [6,7]. A few studies have been published to date; for example, Karlsson et al prepared MFI/MCM-41 composites using two templates (C6 H13 (CH3 ) NBr and C14 H29 (CH3 ) NBr), and optimized the template concentrations and reaction temperature [10]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
