Topic
MCM-41
About: MCM-41 is a research topic. Over the lifetime, 2355 publications have been published within this topic receiving 91416 citations.
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TL;DR: In this paper, mesoporous MnO2 nanoparticles (meso-MnO2NPs) are incorporated in situ into the extra framework of MCM-41 during its synthesis to obtain mesoporosity, morphology, and textural properties.
Abstract: Incorporation of nanoparticles in the extraframework of MCM-41 and its effect on the photocatalytic degradation of phenol has been studied. Mesoporous MnO2 nanoparticles (meso-MnO2NPs) are incorporated in situ into the extraframework of MCM-41 during its synthesis to obtain mesoporous MnO2NPs–MCM-41(MM) materials. Three samples of mesoporous MnO2NPs–MCM-41 have been prepared with Si/Mn ratios 10, 50, and 90. The sample with Si/Mn ratio 10 shows better textural properties compared to the other two samples. Formation of meso-MnO2NPs, reversible coordination of Mn ⇄ Si, and formation the Fe-modified MM-10 nanocomposite (mesoporous Fe@MM–10 NC) are the crucial steps involved in the present investigation. The role of CTAB, NH3, and (NH4)2S2O8 are the key ingredients for the fabrication of meso-MnO2NPs and mesoporous Fe@MM–10 NC. The materials are characterized by LXRD, N2 sorption, and HRTEM to evaluate the mesoporosity, morphology, and textural properties. Mesoporous Fe@MM–10 NC was treated as an efficient ph...
26 citations
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TL;DR: In this paper, mesoporous materials were obtained from two natural silica sources, diatomite and pumicite, under hydrothermal conditions, autogenic pressure and in presence of the surfactant cetyltrimethylammonium bromide (CTAB) as the template.
Abstract: Mesoporous materials were obtained from two natural silica sources, diatomite and pumicite, under hydrothermal conditions, autogenic pressure and in presence of the surfactant cetyltrimethylammonium bromide (CTAB) as the template. Using diatomite, a temperature of 383 K and the following molar ratios in the initial reaction gel: SiO2/Al2O3 = 8.86; CTAB/SiO2 = 0.1; Na2O/SiO2 = 0.10–0.25 and H2O/Na2O = 250–300, the mesoporous material MCM-41 was obtained in a reaction time of 48 h. When pumicite was used, a mesoporous material was obtained in a reaction time of 96 h, a reaction temperature of 423 K and an initial reaction gel with the following molar ratios: SiO2/Al2O3 = 8.86; CTAB/SiO2 = 0.1; Na2O/SiO2 = 0.25 and H2O/Na2O = 330. Copyright © 2006 Society of Chemical Industry
26 citations
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TL;DR: In this article, the MCM-41 family was modified with various metal oxides (Mg, Al, Zr) and then, impregnated with aqueous solution of NH4VO3 and then tested in dehydrogenation of ethane with CO2 at different temperatures.
26 citations
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TL;DR: It was found that the channels of MCM-41 could act as a nanoreactor of propylene polymerization and the polypropylene (PP) contained in the channels had noncrystal structure, however, the PP could grow out of the channels and form some crystals after the active sites on the surface of MCm-41 were destroyed.
Abstract: Propylene polymerization was carried out with MCM-41 supported rac-Et(Ind)2ZrCl2 catalysts, in the presence and absence of β-cyclodextrin. The resultant PP was studied by X-ray diffraction, scannin...
26 citations
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TL;DR: Results of thermal gravimetry-differential thermal analysis reveal the collapse temperature of the order structure starts at approximately 1250 K for mesoporous Cu-SiO2 with 16.8 wt % copper content.
Abstract: A series of mesostructured Cu-SiO2 composites have been synthesized with sodium metasilicate (Na2SiO3) and cuprammonia nitrate (Cu(NH3)4(NO3)2) respectively used as Si and Cu sources. The synthetic procedures were conducted at room temperature, and cetyltrimethylammonia bromide was used as a template. Under our experimental conditions, ordered mesoporous Cu-SiO2 composites could be obtained with a copper content up to 16.8 wt %. Average pore diameters (2.80-3.15 nm), wall thickness (1.30-2.20 nm), and specific surface area (1020-690 m2/g) are found to vary linearly with copper content (0-16.8 wt %). Results of thermal gravimetry-differential thermal analysis reveal the collapse temperature of the order structure starts at approximately 1250 K for mesoporous Cu-SiO2 with 16.8 wt % copper content. As indicated by the outcomes of inductively coupled plasma and X-ray photoelectron spectroscopy studies, copper is mainly incorporated inside the pore wall rather than embedded on the wall surface. Copper species strongly interact with silica, and calcination at high temperatures cannot cause phase separation between silica and copper oxide. Cu status in mesoporous Cu-SiO2 composites is similar to that in copper silicate in neighboring structures. Based on the results, a S+ I- I+ I- mechanism is proposed in which copper entities are surrounded by silicon species during synthesis of the mesostructured composite.
26 citations