Influence of the incorporated metal on template removal from MCM-41 type mesoporous materials

Souza, Luiz K.C. de; Pardauil, Juliana J. R.; Zamian, José Roberto; Filho, Geraldo Narciso da Rocha; Costa, Carlos Emmerson Ferreira da

doi:10.1007/s10973-011-1295-1

Cited by 26 publications

(28 citation statements)

References 20 publications

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“…In the first stage, the catalytic precursors SM, ZSM, and 12SZSM showed a weight loss of about 5% of their initial mass and in the case of 12SZSM-2 it was 10%. These changes occurred between room temperature and 100 ∘ C and are attributed to the removal of physically absorbed water [21]. The second stage of weight loss occurred between 100 and 350 ∘ C; this was due to template agent decomposition [22].…”

Section: Resultsmentioning

confidence: 99%

Porous Silicates Modified with Zirconium Oxide and Sulfate Ions for Alcohol Dehydration Reactions

Benito

García-Alamilla

Enríquez

et al. 2015

Advances in Materials Science and Engineering

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Porous silicates were synthesized by a nonhydrothermal method, using sodium silicate as a source of silica and cetyltrimethylammonium bromide as a template agent. Catalysts were characterized using thermogravimetric analysis, N2physisorption, X-ray diffraction, FTIR spectroscopy, pyridine adsorption, potentiometric titration withn-butylamine, scanning electronic microscopy, and transmission electronic microscopy. The surface area of the materials synthesized was greater than 800 m2/g. The introduction of zirconium atoms within the porous silicates increased their acid strength from −42 to 115 mV, while the addition of sulfate ions raised this value to 470 mV. The catalytic activity for the dehydration of alcohols yields conversions of up to 70% for ethanol and 30% for methanol.

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Section: Resultsmentioning

confidence: 99%

Porous Silicates Modified with Zirconium Oxide and Sulfate Ions for Alcohol Dehydration Reactions

Benito

García-Alamilla

Enríquez

et al. 2015

Advances in Materials Science and Engineering

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“…Therefore, we can infer that surfactant monomers (especially head groups) might create alternative interactions with either cobalt or Co-Br coordination in the early stages of material preparation, thereby undertaking an extended thermal decomposition during calcination. Therefore, this atypical metal-surfactant interaction may inhibit the oxidation process inside the silica matrix3031.…”

Section: Resultsmentioning

confidence: 99%

Tailoring the oxidation state of cobalt through halide functionality in sol-gel silica

Olguin

Yacou

Smart

et al. 2013

Sci Rep

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The functionality or oxidation state of cobalt within a silica matrix can be tailored through the use of cationic surfactants and their halide counter ions during the sol-gel synthesis. Simply by adding surfactant we could significantly increase the amount of cobalt existing as Co3O4 within the silica from 44% to 77%, without varying the cobalt precursor concentration. However, once the surfactant to cobalt ratio exceeded 1, further addition resulted in an inhibitory mechanism whereby the altered pyrolysis of the surfactant decreased Co3O4 production. These findings have significant implications for the production of cobalt/silica composites where maximizing the functional Co3O4 phase remains the goal for a broad range of catalytic, sensing and materials applications.

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“…However, as a main drawback, the porosity and long‐range order of periodic mesoporous MCM‐41 can be destructed during the substitution of framework Si by metallic ions . For example, Al‐incorporated MCM‐41 may exhibit lower degree of long‐range ordinary in the structural hexagonal arrays compared with its all‐Si framework.…”

Section: Introductionmentioning

confidence: 99%

An overall experimental analysis: Effects of synthetic parameters on the degree of order of mesochannels in nano‐sized Al‐MCM‐41

Roohollahi

Halladj

Ebrahimi

et al. 2018

Heteroatom Chemistry

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In an experimental and statistical study, the effects of five synthesis parameters on the degree of order of nano‐sized Al‐MCM‐41 were basically investigated. In a series of designed experiments, hydrothermal conditions (temperature and time), Si/Al, NaOH/Si, and cetyltrimethylammonium bromide/Si molar ratios were studied each at three levels. Degree of order of mesoporous channels was evaluated using small angle XRD. Nitrogen adsorption‐desorption technique, scanning and transmission electron microscopy (SEM‐TEM), and field‐emission SEM were also applied to detect the textural properties and the morphology of prepared nanoparticles. Energy‐dispersive X‐ray spectroscopy and mapping (EDS‐Map), inductively coupled plasma‐optical emission spectroscopy, and small angle X‐ray scattering were provided as complementary analyses. An accurate reduced quadratic equation was proposed as a function of effective terms in good agreement with the experimental results. Based on the analysis of variance, the amount of aluminum incorporated, sodium hydroxide, and the hydrothermal treatment duration was found to possess more dramatic effects on the degree of order than the other factors. The optimum conditions for the synthesis of a well‐ordered Al‐MCM‐41 were also obtained with the lowest template and the minimum hydrothermal duration verified by two validation tests.

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Influence of the incorporated metal on template removal from MCM-41 type mesoporous materials

Cited by 26 publications

References 20 publications

Porous Silicates Modified with Zirconium Oxide and Sulfate Ions for Alcohol Dehydration Reactions

Porous Silicates Modified with Zirconium Oxide and Sulfate Ions for Alcohol Dehydration Reactions

Tailoring the oxidation state of cobalt through halide functionality in sol-gel silica

An overall experimental analysis: Effects of synthetic parameters on the degree of order of mesochannels in nano‐sized Al‐MCM‐41

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