Resorcinol-formaldehyde aerogels and carbon aerogels of different mesoporosities have been used as templates for preparing bimodal zeolites of mesopores. Samples were thoroughly characterized with X-ray diffraction, field emission scanning electron microscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, N(2) adsorption at 77 K, as well as FT-IR spectroscopy and (29)Si nuclear magnetic resonance spectroscopy. The mesoporous ZSM-5 zeolites have additional mesopores of 9-25 nm in widths and 0.07-0.2 cm(3)/g in volumes, besides their perfect inherent micropores. Experimental results show the mesoporous systems of the finally obtained zeolites can be influenced by proper preparation of resorcinol-formaldehyde aerogels and carbon aerogels through solution chemistry. Consequently, zeolites of tunable mesoporosities can be prepared with this unique methodology.
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http://dx.doi.org/10.1021/jp0464167 | DOI Listing |
Langmuir
December 2024
State Key Laboratory of Chemical Resources Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
Diffusion limitations and monofunctional acidity of ZSM-5 molecular sieves affect the catalyst stability and aromatic yield in the reaction of methanol to aromatics (MTA). In this study, based on ZSM-5 nanosheets as parent molecular sieves, Zn-modified hollow ZSM-5 nanosheets were obtained after hydrothermal treatment by adding ZIF-8 or zinc nitrate as a source of Zn while treating with different types and concentrations of alkali solutions. The physical and chemical properties of the fabricated samples and their catalytic performance of methanol aromatization were systematically investigated by a combination of XRD, TEM, N adsorption-desorption, NH-TPD, Py-IR, Al MAS NMR, Si MAS NMR, XPS, and TG characterization analyses and MTA experimental evaluation.
View Article and Find Full Text PDFMolecules
December 2024
Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH12 7NT, UK.
In this study, we investigated the pyrolysis of cellulose, lignin, phenylalanine and textile wool waste using microscale thermogravimetric analysis (TGA) and a gram-scale fixed bed reactor. The pyrolysis was conducted at 500 °C and 1 bar N, using Al- and Li-doped mesoporous KIL-2 and ZSM-5 catalysts for comparison. Our results show that amorphous Al-KIL-2 catalyst was the most efficient in producing aromatics from cellulose and lignin.
View Article and Find Full Text PDFChemphyschem
December 2024
Department of Chemical and Biomolecular Engineering, School of Energy Science and Engineering, Vidyasirimedhi Institute of Science and Technology, 555 Moo 1 Pa Yup Nai, Wang Chan, Rayong, 21210, Thailand.
To date, preparing materials with highly dispersed metal nanoparticles without metal agglomeration on a solid support is challenging. This work presents an alternative approach for synthesizing NiCo species on hierarchical ZSM-5 materials derived from a ZSM-5@NiCoAl-LDHs composite. The designed material was prepared by the growth of a NiCo-layered double hydroxides (LDHs) precursor on the surface of hierarchical ZSM-5 nanosheets.
View Article and Find Full Text PDFJ Hazard Mater
November 2024
State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China. Electronic address:
Inorg Chem
November 2024
School of Chemistry and Environmental Engineering, Anyang Institute of Technology, Anyang 455000, People's Republic of China.
As an important nonoil route for acquiring aromatics, the highly efficient conversion of methanol to aromatics over Zn/ZSM-5 zeolites remains an ongoing challenge. In this work, we developed a uniform loading approach of zinc and further combined it with a hollow capsule structure to design the high-performance Zn/ZSM-5 catalyst. The electrostatic assembly among EDTA, -butylamine and negative silica-alumina gel gave rise to an "Inorganic-Organic Hybrid Sphere" in form of Na·{[(SiO)Al]/(SiO)(-butylamine)(EDTA)(-butylamine)(SiO), which further transformed into mesoporous aluminosilicates sphere (MASS) through calcination.
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