Effect of cosolvent organic molecules on the adsorption and structural properties of soft-templated ordered mesoporous alumina

Grant, Stacy M.; Jaroniec, Mietek

doi:10.1016/j.jcis.2011.09.064

Cited by 14 publications

(6 citation statements)

References 34 publications

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“…These reported methods were mostly based on using sacrificial anionic, cationic, or non‐ionic templates as a structural directing agent to prepare mesoporous alumina . Also there are reports based on larger molecular surfactant like non‐ionic poly (ethylene oxide) surfactants or primary amine surfactants, tri block copolymer P123 or F127, poly ethylene glycol used as structure directing agent . All the reported methods are expensive, time consuming and based on complex multistep protocol.…”

Section: Catalyst Code and Weight Of The Each Starting Materialmentioning

confidence: 99%

Facile Synthesis of Mesoporous Alumina with Tunable Morphology using Template Free Method

2020

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Mesoporous alumina (MA) with interesting morphologies of flower or three‐dimensional hierarchical spheres like nanostructures were synthesized in the absence of any template. Hydrothermal synthesis strategy was applied for synthesis of mesoporous γ‐ alumina with tunable properties like BET surface area, pore volume, pore size and superior acidic property. Over all experiments were conducted systematically using aluminum sulfate hydrolysis, precipitation, growth/nucleation. The formation of flower like structures of γ‐Al2O3 were characterized by X‐ray powder diffraction (XRD), N2physisorption, scanning electron microscope (SEM), Temperature programmed ammonia desorption (TPD) for acidity, Nuclear magnetic resonance (NMR) spectroscopy. In order to study the effect of chelating agents like urea and role of complexing agents, a series of contrast experiments were carried out. The novel synthesis methodology yielded MAs with exceptionally high surface areas, pore volumes, uniform pore size distributions and versatile acidic strengths. This present investigation provided a simple and effective approach for preparing mesoporous alumina and the different kinds of morphologies structures of alumina can be controlled precisely by choosing appropriate complexing agents and optimum quantity of precipitating agents. This approach of work not only allows us to investigate the growth mechanism of the final product, but also reduces cost and the environmental pollution effectively than other template methods.

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Section: Catalyst Code and Weight Of The Each Starting Materialmentioning

confidence: 99%

Facile Synthesis of Mesoporous Alumina with Tunable Morphology using Template Free Method

2020

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“…Since there are a significant number of hydroxyl groups on the surfaces of the alumina precursor, excess alcohol is adsorbed on the surface planes of the bohemite crystallite (alumina precursor) via hydrogen bonding. This reduces the surface energy of the alumina precursor and inhibits the polymerization of the primary crystallites [46][47][48]. In addition, excess alcohol enhances the mobility of the alumina precursor and avoids pile stacking of the alumina plates.…”

Section: The Effect Of Excess Alcoholmentioning

confidence: 99%

A statistical approach to control porosity in silica-doped alumina supports

Mardkhe

Lawson

Huang

et al. 2015

Microporous and Mesoporous Materials

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A split-plot statistical design was used to identify and systematically study the effects of synthesis variables on the pore properties of silica-doped alumina (SDA) from data obtained for 96 samples. Seven preparation variables (mixing method, time, environment; calcination ramp rate; drying temperature, environment; and alcohol concentration) were found to alter surface area, pore volume, and pore diameter over wide ranges, i.e. factors of 1.8, 1.4, and 3.3, respectively. Large pore diameters (> 40 nm) were obtained by addition of excess alcohol. Large pore volumes (> 2 cm 3 /g) were obtained by drying before calcination at 100C for 24 h. High surface area (> 400 m 2 /g) was obtained when no alcohol was used. The gamma phase of all SDA samples was thermally stable to 1200C. Using split-plot statistical analysis of the experimental data, models were developed which predict quantitatively the relationship between surface properties (surface area, pore volume and pore diameters) and synthesis parameters. Based on these models, optimal conditions to produce SDA samples with large (40-60 nm) or medium (16-19 nm) pore diameters, high surface area (>250 m 2 /g) and large pore volume (>1 cm 3 /g) are quantitatively predicted. Model predictions of optimal conditions were accurately

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“…The evaporation induced self-assembly (EISA) method is another soft-template self-assembly approach for the successful preparation of ordered mesoporous materials, especially ordered mesoporous metal oxides [ 7 , 8 , 21 , 22 , 23 ]. Via such a method, a series of ordered mesoporous alumina materials with different mesostructures and tunable mesoporous sizes have also been successfully prepared by adjusting the hydrophilic-hydrophobic properties of surfactants or introducing suitable catalysts into the initial synthesis solution [ 8 , 24 , 25 , 26 ]. During the EISA process, the utilization of volatile non-aqueous solvents (such as anhydrous ethanol and tetrahydrofuran) can effectively slow down the hydrolysis-condensation rate of aluminum precursors, and a self-assembly ordered organic-inorganic composite micelle structure can be induced by gradually increasing the surfactant concentration during the solvent evaporation process.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Ordered Mesoporous Zr-Al Composite Oxides with Excellent Structural and Textural Properties and Extremely High Stability

Liu

et al. 2020

Materials

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Ordered mesoporous Zr-Al composite oxide materials (denoted as OMZA-x) with different Zr contents have been synthesized by a solvent evaporation-inducing self-assembly procedure associated with a thermal treatment at 100 °C. A cooperative co-assembly process of amphiphilic triblock copolymer F127 molecules and inorganic hydroxyl species originated from the hydrolysis of Zr and Al precursors was proposed to explain the synthesis of OMZA-x. Compared to ordered mesoporous alumina prepared without introducing Zr species, the resultant OMZA-x exhibited a much more ordered mesostructure combined with a distinct increase in the pore volume and specific surface area. The highly homogenous doping of Zr into the mesopore walls together with the formation of Zr-O-Al bonds can effectively enhance the thermal and hydrothermal stability of OMZA-x. For instance, the ordered mesostructure and excellent textural properties of OMZA-6 prepared with the optimum atomic ratio of Al to Zr of 6 could be well maintained even after a high-temperature treatment at 1000 °C for 1 h or a hydrothermal treatment at 100 °C for 6 h.

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Effect of cosolvent organic molecules on the adsorption and structural properties of soft-templated ordered mesoporous alumina

Cited by 14 publications

References 34 publications

Facile Synthesis of Mesoporous Alumina with Tunable Morphology using Template Free Method

Facile Synthesis of Mesoporous Alumina with Tunable Morphology using Template Free Method

A statistical approach to control porosity in silica-doped alumina supports

Synthesis of Ordered Mesoporous Zr-Al Composite Oxides with Excellent Structural and Textural Properties and Extremely High Stability

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