Showing papers on "MCM-41 published in 2021"
TL;DR: In this article, a mesoporous MCM-41 composite was synthesized through the surfactant-assisted sol-gel technique, and different weight percentages of phosphotungstic acid (PTA) were loaded over Zr-MCM41 composites by wet impregnation method.
39 citations
TL;DR: In this paper, Zirconia-based mesoporous MCM-41 was successfully prepared then loaded with different content of sulfate (5, 10, 15, 25, 40 and 50 wt%) through the wet impregnation method.
34 citations
TL;DR: This catalyst, used for the first time for pyrolysis of lignocellulosic biomass, is proposed as a tool to reduce coke agglomeration and increase hydrocarbon yields and characterization and catalytic testing results suggest that the digestion temperature plays a more important role in the catalyst synthesis than the crystallization temperature.
31 citations
TL;DR: In this paper, the effects of temperature, catalysts, seaweed and cellulose ratio were examined on product yields distribution and bio-oil compositions by catalytic co-pyrolysis.
Abstract: Catalytic co-pyrolysis of seaweed Enteromorpha clathrata (EN) and cellulose (CEL) with catalysts ZSM-5 and MCM-41 was investigated by TG, Py–GC/MS and fixed-bed experiments. The effects of temperature, catalysts, seaweed and cellulose ratio were examined on product yields distribution and bio-oil compositions by catalytic co-pyrolysis. The maximum bio-oil yield was recorded at the ratio of 1:1 (EN and CEL) with ZSM-5/MCM-41 at 500 °C on co-pyrolytic process. The interaction of radicals and faster heat transfer rate of EN/CEL induces the synergistic effects with catalysts. The advantage of mesoporous molecular sieve along with acidic microporous zeolite of ZSM-5/MCM-41 improved the cracking, dehydration, decarbonylation, decarboxylation, dealkylation, aromatization, oligomerization and deamination reactions. The overall study revealed that the amount of N-containing compounds were decreased and significantly elevated bio-oil production with increased furans and aromatics.
29 citations
TL;DR: In this article, the incorporation of sulfamic acid (SA) into mesoporous silica (MCM-41) introduced an effective approach in numerous multicomponent reactions, such as 3,4-dihydro-pirimidin-2(1H)-ones (DHPs), 7-hydroxy-4-methylcoumarin and 14-Phenyl-14H-dibenzo [a, j] xanthene.
27 citations
23 citations
TL;DR: In this article, the performance and activity of MCM-41-based catalysts were characterized by different techniques that confirmed the formation of oxides of the different metals on the surfaces of all materials Low-angle X-ray diffraction (XRD) analyses showed that calcination resulted in the incorporation of metallic Zn, Fe, Cr, Fe and Cr in the framework of MCMC-41.
Abstract: MCM-41 based catalysts (molar ratio Si/Al = 40) were prepared by a hydrothermal route, modified by ionic exchange with different metals (Cu, Cr, Fe and Zn) and finally calcined at 550 °C The catalysts were fully characterized by different techniques that confirmed the formation of oxides of the different metals on the surfaces of all materials Low-angle X-ray diffraction (XRD) analyses showed that calcination resulted in the incorporation of metallic Zn, Fe and Cr in the framework of MCM-41, while in the case of Cu, thin layers of CuO were formed on the surface of MCM-41 The solids obtained were tested in the catalytic wet peroxide oxidation (CWPO) of acetaminophen at different temperatures (25–55 °C) The activity followed the order: Cr/MCM-41 ≥ Fe/MCM-41 > Cu/MCM-41 > Zn/MCM-41 The increase of the reaction temperature improved the performance and activity of Cr/MCM-41 and Fe/MCM-41 catalysts, which achieved complete conversion of acetaminophen in short reaction times (15 min in the case of Cr/MCM-41) Fe/MCM-41 and Cr/MCM-41 were submitted to long-term experiments, being the Fe/MCM-41 catalyst the most stable with a very low metal leaching The leaching results were better than those previously reported in the literature, confirming the high stability of Fe/MCM-41 catalysts synthesized in this study
22 citations
TL;DR: In this paper, a series of CuZn/MCM-41 catalysts was synthesized by four different routes; one pot hydrothermal synthesis (OPMCM), co-impregnation (COMCM), serial impregnation and copper impregnated on Zn-MCM41 (ZNMCM).
21 citations
TL;DR: In this paper, a green synthesis of MCM-41 and an efficient Ni/SiO2 catalyst derived from nickel phyllosilicate for CO2 methanation was presented.
20 citations
TL;DR: In this paper, a 20% Ni/H-ZSM-5/MCM-41 composite material, synthesized from alkaline desilication of a conventional H-Z SM-5(Si/Al) and surfactant-recrystallization process, was used as support of Ni-catalyst in CDM.
20 citations
TL;DR: A magnetically-recoverable multifunctional catalyst (Fe3O4/ZrO2@MCM-41) was tailored by the impregnation of ZrO 2 supported on mesoporous MCM41 coated Fe3O 4 nanoparticles, which successfully served as a monolithic catalyst for the cascade conversion of furfural (FAL) giving high yield to γ-valerolactone (GVL), a versatile platform molecule as mentioned in this paper.
TL;DR: Results demonstrate that the MCM-41 adsorbent can be easily regenerated by thermal desorption in air, and the cumulative heel on the adsorbENT can be markedly reduced by increasing the desorptive temperature, making it a promising adsorbents for VOCs abatement.
TL;DR: In this article, the mesoporous solid of MCM-41 was first reacted with (3-chloropropyl)triethoxysilane (CPTES) before alanine is covalently bonded onto the hybrid support as confirmed by TGA/DTG, IR and UV-Raman spectroscopy analyses.
TL;DR: In this article, Pd-Pt/MCM-41 supports with various structural properties and morphologies were synthesized by self-assembly with different amounts of ammonia solution as a mineralizing agent.
TL;DR: Nickel modified Al-containing MCM-41 nanoparticles with Si/Al molar ratio ranging from 10 to 60 were synthesized by direct insertion of aluminum at room temperature followed by wet impregnation as mentioned in this paper.
TL;DR: In this paper, the mesoporous MCM-41 was used as support and ZnO, CeO2, ZrO2 as active agents and promoters for the catalyst preparation, and (Li-Na-K) NO3·MgO as a CO2 adsorbent was prepared by the wet mixing method.
TL;DR: In this article, the performance of Ni-Mo2C/MCM-41 catalysts in jatropha oil (JO) conversion showed a volcano-like trend over the catalysts with increasing CH4 content from 15% to 50% in the preparation process.
TL;DR: In this article, the mesoporous MCM-41 layers with different diameters are prepared rationally to reach this goal and in-depth understand the role of mesopore sizes on acidity and Pt properties as well as the isomerization performance.
TL;DR: In this article, a mesoporous copper-attached functionalized MCM-41 with the DL-Pyroglutamic acid framework has been produced through a post-synthetic method.
Abstract: In the current study, a mesoporous copper-attached functionalized MCM-41 with the DL-Pyroglutamic acid framework has been produced through a post-synthetic method. The MCM-41 functionalization technique has been used to synthesize this novel heterogeneous catalyst. The material has been identified fully using XRD, FT-IR, BET, EDX, elemental mapping, SEM, and TGA. This catalyst displays high catalytic performance in the one-step thioether formation (C–S) reaction and synthesis of 5-substituted 1H-tetrazoles. The main aspects of this economical copper-catalyzed procedure are green synthesis, slighter experimental conditions, and less reaction time with no additives. Further benefits comprise experimental comfort of handling, secure replacement to dangerous, damaging, and poisoning regular Lewis’s acid catalysts, and reusability with constant catalytic performance.
TL;DR: In this article, the catalytic activity of the heterogeneous catalyst for transesterification of glycerol into carbonate, a versatile compound, was investigated with different active metals impregnated on MCM-41 (Mobil Composition of Matter No. 41) framework.
TL;DR: In this paper, a Ni-Ce/Al-MCM-41 catalyst with enhanced activity at low temperatures via one-pot hydrothermal synthesis using kaolin as a silica precursor for CO2 methanation was investigated.
Abstract: We prepared Ni–Ce/Al-MCM-41 catalyst with enhanced activity at low temperatures via one-pot hydrothermal synthesis using kaolin as a silica precursor for CO2 methanation and investigated the influence of Ce addition on the catalytic activity enhancement. The as-synthesized Al-MCM-41 possessed hexagonal mesoporous silica with a surface area of 436 m2/g and a mesopore of 3.8 nm, allowing the incorporation of Ni and Ce into the Al-MCM-41 structure. In a fixed-bed tubular reactor, the catalytic performance of the as-prepared catalyst was evaluated in terms of CO2 conversion, CH4/CO selectivity, CH4 yield, reaction rates per catalyst mass (rm), and catalyst surface (rs), TOF, activation energy, and the deactivation rates of its corresponding activities at 250–550 °C and 1 atm. As the Ce content increased, the catalytic activity greatly improved due to the improved Ni dispersion and higher CO2 adsorption, although the porosity of the catalyst significantly decreased. With the optimum Ce content, 100% CH4 yield was achieved at 350 °C and weight hourly space velocity (WHSV) = 20,000 mL g−1 h−1. The optimum catalyst also exhibited high stability with a deactivation rate of −0.072% YCH4 g−1 h−1 over 76 h, attributed to the strong interaction between Ce and Al in Al-MCM-41.
TL;DR: In this paper, the authors examined the preparation of MCM-41, Ni-MCM-51 and Co-MCm-41 from silica extracted from rice husk ash (RHA) via sol-gel technique.
Abstract: This study examined the preparation of MCM-41, Ni-MCM-41 and Co-MCM-41 from silica extracted from rice husk ash (RHA) via sol–gel technique. The materials were characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), Diffuse reflectance UV–Vis (DR/UV–Vis),Energy Dispersive X-ray Spectrometry (EDX), N 2 adsorption–desorption and NH3 TPD. XRD and TEM analyses showed reduction in the long range order upon the introduction of heteroatoms into MCM-41 framework. Successful substitution of Si 4 + with metal cations was verified by the shifting in the siloxane (Si-O-Si) bond. Presence of nickel phyllosilicates was evidenced from the FT-IR and DR/UV–Vis investigations. Mesoporous behavior with capillary condensation was unchanged even after the incorporation of Ni and Co species into the MCM-41 matrix. MCM-41 and modified MCM-41 catalysts were evaluated in the liquid-phase oxidation of styrene for 4 h under the influence of reaction parameters such as reaction temperature, catalyst loading, types of solvent and molar ratio of styrene : H2O2. Under the optimum condition of 343 K, 0.20 g catalyst, 1:4 molar ratios and DMF as the reaction medium, the activity was found to increase following the trend: Ni-MCM-41 (79.9%) >Co-MCM-41(56.6%) > MCM-41 (40.7%). Benzaldehyde was the sole product over Ni-MCM-41 and Co-MCM-41 while MCM-41 gave benzaldehyde (96.0%) and styrene oxide (4.0%). Surface characteristics and TPD acidity strength was found to govern the catalysis. Negligible leaching (0.448 ppm) and exceptional activity during successive reruns demonstrates that Ni-MCM-41 was beyond doubt, heterogeneous in nature. This research signifies a successful conversion of waste biomass into value added products.
TL;DR: In this paper, Pd-Fe catalyst was recognized as a suitable catalyst for upgrading of lignin-derived bio-oil since it produced more deoxygenated products and less gas-phase yield than PdCo catalyst.
TL;DR: Hierarchical composites of MCM-41 on zeolite Beta were synthesized by in-situ hydrothermal technique, characterized and their catalytic performance for converting heavy reformate into valuable xylenes was evaluated.
TL;DR: In this article, the adsorption potential of aminopropyl functionalized mesoporous silica materials obtained by co-condensation and post grafting methods was evaluated.
Abstract: The adsorptive potential has been evaluated for the aminopropyl functionalized mesoporous silica materials obtained by co-condensation and post grafting methods. Nitrogen sorption, small angle neutron and X-ray scattering (SANS and SAXS) demonstrated high surface area and well-ordered hexagonal pore structure suitable for applications as adsorbents of metals from waste waters. A comparison of Cr(VI) adsorption properties of the materials prepared by different functionalization methods has been performed. The obtained results demonstrated the adsorption capacity due to the affinity of the chromium ions to the amino groups, and showed that co-condensation of tetraethoxysilane (TEOS) and 3-aminopropyl triethoxysilane (APTES) resulted in higher metal sorption capacity of the materials compared to post-synthesis grafting of aminopropyl groups onto the mesoporous silica particles.
TL;DR: In this article, new recyclable mesoporous-supported iron particles with the ligand and without ligand have been developed through post-functionalization modification of silica MCM-41.
TL;DR: In this paper, mesoporous Al-MCMMCM-41 nanospheres with variable size (35−90 nm) were synthesized by the sol-gel method.
TL;DR: In this paper, the intact Lewis metal (ZrIV) substituted Keggin polyoxometalate (POM) was used to construct hybrid catalysts for esterification reaction.
TL;DR: In this paper, the mesoporous moisture regulation material Al-MCM-41 (MRMCM) was fabricated using liquid crystal display waste glass (LCDwg) and chemical mechanical polishing sludge (CMPs).