Influence of alcohol solvents on morphology of hollow silica–alumina composite spheres and their activity for hydrolytic dehydrogenation of ammonia borane

Toyama, Naoki; Ohki, Shinobu; Tansho, Masataka; Shimizu, Tadashi; Umegaki, Tetsuo; Kojima, Yoshiyuki

doi:10.1007/s10971-016-4287-6

Cited by 7 publications

(7 citation statements)

References 56 publications

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“…Toyama et al [72] prepared hollow silica-alumina (SiO 2 -Al 2 O 3 ) composite spheres via the sol-gel method using polystyrene particles as a template. Methanol, ethanol, and 2-propanol were separately used as solvents to investigate the effect of alcohol solvents on the morphology of hollow SiO 2 -Al 2 O 3 composite spheres.…”

Section: Synthesis Of Hollow Sphere Materials By the Sol-gel Methodsmentioning

confidence: 99%

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Synthesis of Hollow Sphere and 1D Structural Materials by Sol-Gel Process

Zhang

2017

Materials

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The sol-gel method is a simple and facile wet chemical process for fabricating advanced materials with high homogeneity, high purity, and excellent chemical reactivity at a relatively low temperature. By adjusting the processing parameters, the sol-gel technique can be used to prepare hollow sphere and 1D structural materials that exhibit a wide application in the fields of catalyst, drug or gene carriers, photoactive, sensors and Li-ion batteries. This feature article reviewed the development of the preparation of hollow sphere and 1D structural materials using the sol-gel method. The effects of calcination temperature, soaking time, pH value, surfactant, etc., on the preparation of hollow sphere and 1D structural materials were summarized, and their formation mechanisms were generalized. Finally, possible future research directions of the sol-gel technique were outlined.

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Section: Synthesis Of Hollow Sphere Materials By the Sol-gel Methodsmentioning

confidence: 99%

“…Schematic illustration of formation process of the hollow spheres with different coating time (6, 17, 36 h) [72]. …”

Section: Figurementioning

confidence: 99%

Synthesis of Hollow Sphere and 1D Structural Materials by Sol-Gel Process

Zhang

2017

Materials

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“…In order to evaluate the effect of the morphology and the dispersion of active aluminum species in the hollow spheres, the relation between the ratios of four-coordinated aluminum species and the activity for hydrogen evolution amount from aqueous solutions in the presence of various silica-aluminum composite particles. The relation calculated from some of our previous studies [52,61,62] was shown in Figure 5. From this figure, the hollow spheres showed unexpected high activity as compared with the fine particles, although the ratio of four-coordinated aluminum species in the hollow spheres was not significantly higher than the ratio of the fine particles.…”

Section: Improvement Of Dispersion Of Active Species Of Hollow Silicamentioning

confidence: 98%

“…The acid sites can generally increase with the increase of four-coordinated aluminum species, which are well-dispersed active species. We investigated the influence of various preparation conditions such as promoters of sol-gel reaction for the formation of the shell of the hollow spheres, alcohol solvents, aluminum precursors, and so on, on the dispersion of the active aluminum species of hollow silica-alumina composite spheres and their activity for hydrolytic dehydrogenation of ammonia borane [60][61][62].…”

Section: Improvement Of Dispersion Of Active Species Of Hollow Silicamentioning

confidence: 99%

Role of Interparticle Space in Hollow Spheres of Silica-Based Solid Acids on Their Acidic Properties and Activity for Hydrolytic Dehydrogenation of Ammonia Borane

Umegaki¹,

Toyama²,

Kojima³

2018

Porosity - Process, Technologies and Applications

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Porous materials with micropores and mesopores have attracted much attention as materials potentially applied in various fields such as absorbents, catalysts, energy storage, and so on. The kind of materials showed intrinsic properties compared with other types of materials such as fine particles. This chapter reviewed our recent research about hollow silica-alumina composite spheres for the hydrolytic dehydrogenation of ammonia borane. This chapter has mainly discussed about the role of interparticle space in the hollow spheres on their acidic properties and activity for the hydrolytic dehydrogenation of ammonia borane.

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“…Additionally, NH 3 BH 3 releases hydrogen via a hydrolysis reaction in the presence of suitable acids and catalysts at room temperature (Eq. (1)) [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]: NH 3 BH 3 + 2H 2 O → NH 4 + + BO 2  + 3H 2 (1) It has been reported that solid acids such as H-type zeolites (H-BEA and H-MOR) show high activity for the hydrolytic dehydrogenation of NH 3 BH 3 [13]. We have reported that hollow silica-alumina composite spheres show higher activity compared with fine particles [14].…”

Section: Introductionmentioning

confidence: 99%

Influence of morphology of hollow silica–alumina composite spheres on their activity for hydrolytic dehydrogenation of ammonia borane

et al. 2017

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Hollow silica-alumina composite spheres were prepared by a polystyrene (PS) template method using various amounts of PS suspension. Homogeneous hollow spheres prepared using 40 g were found to be with a diameter of about 300 nm in scanning electron microscopy, and transmission electron microscopy demonstrated their hollow sphere morphology. From the nitrogen adsorption isotherm results, the homogeneous hollow spheres prepared using 40 g of the PS suspension were found to be an ordered pore structure. The activities of the hollow spheres prepared using various amounts of the PS suspension for hydrolytic dehydrogenation of ammonia borane were compared. The results showed that 10, 7, and 6 mL of hydrogen were evolved from the aqueous ammonia borane solution in about 40 min in the presence of the hollow spheres prepared using 40, 80, and 120 g of PS suspension, respectively. The homogeneous hollow spheres with an ordered pore structure showed the highest activity among all the hollow spheres. The amount of acid sites and the coordination number of aluminum active species were characterized using neutralization titration and solid-state 27 Al magic angle spinning nuclear magnetic resonance spectroscopy. The homogeneous hollow spheres with an ordered pore structure had high amount of acid sites and 4-coordinated aluminum species. The relative proportion of 4-coordinated aluminum species was related to the dispersion of aluminum species. These results indicate that the homogeneous hollow spheres with an ordered pore structure showed the high activity because of high amount of acid sites induced by the highly dispersed aluminum species.

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Influence of alcohol solvents on morphology of hollow silica–alumina composite spheres and their activity for hydrolytic dehydrogenation of ammonia borane

Cited by 7 publications

References 56 publications

Synthesis of Hollow Sphere and 1D Structural Materials by Sol-Gel Process

Synthesis of Hollow Sphere and 1D Structural Materials by Sol-Gel Process

Role of Interparticle Space in Hollow Spheres of Silica-Based Solid Acids on Their Acidic Properties and Activity for Hydrolytic Dehydrogenation of Ammonia Borane

Influence of morphology of hollow silica–alumina composite spheres on their activity for hydrolytic dehydrogenation of ammonia borane

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