Effects of ammonia/silica molar ratio on the synthesis and structure of bimodal mesopore silica xerogel

Wang, Xiaozhong; Li, Wenhuai; Zhu, Guangshan; Qiu, Shilun; Zhao, Dongyuan; Zhong, Bing

doi:10.1016/j.micromeso.2004.03.021

Cited by 58 publications

(17 citation statements)

References 25 publications

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“…1b, which mainly centered at 1.0 nm. The isotherm showed textural mesopores resulting from the interparticle voids [19]. The BET specific surface area of ZSM-5 supported catalyst is 357 m 2 g -1 lower than that of alkaline treated support.…”

Section: Physic-chemical Properties Of Catalystsmentioning

confidence: 93%

Application of mesoporous ZSM-5 as a support for Fischer–Tropsch cobalt catalysts

Wang

Zhao

et al. 2014

J Porous Mater

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The effect of mesoporous structure of ZSM-5 on the properties of cobalt-based catalysts for FischerTropsch synthesis was studied in this work. ZSM-5 and amorphous SiO 2 supports have also been applied for comparison. It was shown that post treatment of ZSM-5 catalyst by NaOH solution improved the catalytic performance to produce higher amount of liquid hydrocarbons. The hierarchical structure combining with the acidity of meso-ZSM-5 had great effect on increasing the selectivity to C 5-18 hydrocarbons and preventing the formation of CH 4 . The more acid sites of the support promoted catalytic cracking reaction of olefinic hydrocarbons to light hydrocarbons, the lower olefin to paraffin ratio was observed over Co/meso-ZSM-5 catalyst compared with that of Co/ SiO 2 catalyst.

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Section: Physic-chemical Properties Of Catalystsmentioning

confidence: 93%

Application of mesoporous ZSM-5 as a support for Fischer–Tropsch cobalt catalysts

Wang

Zhao

et al. 2014

J Porous Mater

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“…The second sharp step, at a high relative pressure (p/p0 > 0.8), implies the coexistence of textural mesopores, corresponding to the filling of the interparticle spaces among the nanoparticles. The secondary pore size was highly dependent on the rate of hydrolysis and condensation of TEOS and was mainly controlled by the ammonia/silica molar ratio [28,34]. As shown in Table 1, the size of textural mesopores changed from 18 to 30 nm with an increase in the ammonia/silica molar ratio.…”

Section: Mechanism For the Synthesis Of Bimodal Mesoporous Silicamentioning

confidence: 96%

“…The synthesis procedure has been reported elsewhere [27,28]. First, 2.1 g of cetyltrimethylammonium bromide (CTAB) was dissolved in 40 mL of deionized water, with stirring at room temperature.…”

Section: Catalyst Preparationmentioning

confidence: 99%

High performance Pd catalysts supported on bimodal mesopore silica for the catalytic oxidation of toluene

Qiao

et al. 2015

Chinese Journal of Catalysis

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A series of bimodal mesoporous silica (BMS-x)-supported Pd catalysts were successfully prepared by a facile sol-gel approach, followed by an impregnation method. The synthesized catalysts were characterized by several analytical techniques and the oxidation of toluene was used to evaluate their catalytic performance. Textural analysis showed that all samples had high surface areas (~1000 m 2 /g), large pore volumes (~1.2 cm 3 /g) and uniform mesopore size (~2.6 nm). Defining the level of ammonia solution to within a certain range resulted in the catalysts possessing a typical bimodal mesoporous structure with an intraparticle framework mesopore and an interparticle textural mesopore (18-40 nm). Transmission electron microscopy observations and CO chemisorption results revealed that this unique bimodal mesoporous structure helped to decrease the particle size of Pd nanoparticles and could further enhance their dispersion. Activity tests revealed the Pd/BMS-5-Pd/BMS-20 catalysts with a bimodal mesopore structure possessed superior catalytic performance for the oxidation of toluene compared to Pd/BMS-30 with a unimodal mesopore structure. More importantly, compared with the Pd/MCM-41 and Pd/MCM-48 catalysts, Pd/BMS-15 had improved hydrothermal stability and catalytic performance at a high gas hourly space velocity of 70000 h −1 . These results indicate the potential application of the catalysts for the elimination of volatile organic compounds.

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“…NO 3 − will block the adsorption of silicate ions on micelles and delay the formation of the silica/surfactant mesophases. This can cause the incomplete interaction between silica species and surfactant, therefore smaller pores were formed by the template and the larger pore was formed by the agglomeration of silica nanoparticles during the hydrolysis-condensation [24,25] process. This could be the reason for the formation of bimodal pore system.…”

Section: The Nitrogen Sorption Analysismentioning

confidence: 99%

The oxidation of styrene by chromium–silica heterogeneous catalyst prepared from rice husk

Adam

Iqbal

2010

Chemical Engineering Journal

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Effects of ammonia/silica molar ratio on the synthesis and structure of bimodal mesopore silica xerogel

Cited by 58 publications

References 25 publications

Application of mesoporous ZSM-5 as a support for Fischer–Tropsch cobalt catalysts

Application of mesoporous ZSM-5 as a support for Fischer–Tropsch cobalt catalysts

High performance Pd catalysts supported on bimodal mesopore silica for the catalytic oxidation of toluene

The oxidation of styrene by chromium–silica heterogeneous catalyst prepared from rice husk

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