Preface

Vansant, Etienne F.; Voort, Pascal Van Der; Vrancken, K.C.

doi:10.1016/s0167-2991(06)81508-9

Cited by 276 publications

(245 citation statements)

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“…The total amount of surface Si-OH hydroxyls on silica after pretreatment at 100°C is estimated to be 4-5 OH/nm 2 . 49 Both Raman and NIR DRS experiments show that the surface Si-OH hydroxyls are almost completely consumed by deposition of the surface vanadium oxide species at maximum coverage of ∼2.6 V atoms/ nm 2 . The maximum Si-O -ligands needed for anchoring the V atoms at maximum coverage is about 7.8 Si-O groups/nm 2 , which is higher than the total amount of the surface Si-OH hydroxyls during impregnation.…”

Section: Discussionmentioning

confidence: 99%

In Situ Spectroscopic Investigation of Molecular Structures of Highly Dispersed Vanadium Oxide on Silica under Various Conditions

et al. 1998

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The molecularly dispersed V 2 O 5 /SiO 2 supported oxides were prepared by the incipient wetness impregnation of 2-propanol solutions of V-isopropoxide. The experimental maximum dispersion of surface vanadium oxide species on SiO 2 was achieved at ∼12 wt % V 2 O 5 (∼2.6 V atoms/nm 2 ). The surface structures of the molecularly dispersed V 2 O 5 /SiO 2 samples under various conditions were extensively investigated by in situ Raman, UVvis-NIR DRS and XANES spectroscopies. The combined characterization techniques revealed that in the dehydrated state only isolated VO 4 species are present on the silica surface up to monolayer coverage. Interestingly, the three-member siloxane rings on the silica surface appear to be the most favorable sites for anchoring the isolated, three-legged (SiO) 3 VdO species. Hydration dramatically changes the molecular structure of the surface vanadium oxide species. The specific structure of the hydrated surface vanadium oxide species is dependent on the degree of hydration. The molecular structure of the fully hydrated vanadium oxide species closely resembles V 2 O 5 ‚nH 2 O gels, rather than V 2 O 5 crystallites. The fully hydrated surface vanadium oxide species are proposed to be chain and/or two-dimensional polymers with highly distorted square-pyramidal VO 5 connected by V-OH-V bridges, which are stabilized on the silica surface by the sixth neighbor of Si-OH hydroxyls via Si-OH‚‚‚V hydrogen bonds. In analogy to the hydration process, alcoholysis occurs during methanol chemisorption, and similar molecular structures are proposed to interpret the interaction between methanol molecules and the surface vanadium oxide species on silica.

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Section: Discussionmentioning

confidence: 99%

In Situ Spectroscopic Investigation of Molecular Structures of Highly Dispersed Vanadium Oxide on Silica under Various Conditions

et al. 1998

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“…Silica, which is only weakly acidic, is well-suited as a solid support for bifunctional catalysts. Its surface is readily modified either by post-synthetic grafting [22] or by co-condensation during its synthesis [23,24]. In particular, an anchored thiol can serve as a precursor to both the desired promoter and acid sites, Scheme 2.…”

Section: Introductionmentioning

confidence: 99%

Bifunctional Solid Catalysts for the Selective Conversion of Fructose to 5-Hydroxymethylfurfural

et al. 2010

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Solid catalysts based on SBA-15 silica were designed for the conversion of fructose to 5-hydroxymethylfurfural (HMF). The catalysts incorporate thioether groups that may promote the tautomerization of fructose to its furanose form, as well as sulfonic acid groups to catalyze its dehydration. The materials were characterized by elemental analysis, X-ray diffraction, N 2 adsorption/ desorption, and solid-state 13 C and 29 Si CP/MAS NMR spectroscopy. Functional groups incorporated into mesoporous silica by co-condensation are more robust under the reaction conditions (water at 180°C) than those grafted onto a non-porous silica. The bifunctional mesoporous catalyst achieved a selectivity for HMF of 74% at 66% fructose conversion.

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“…For example, aminosilane-modified silica gel has been applied as a CO2 adsorbent 6) . Aminosilane-modified silica has been extensively studied because of the wide range of applications 7) . However, it is difficult to modify the micropore walls of silica with aminosilane molecules due to steric hindrance 7) .…”

Section: Introductionmentioning

confidence: 99%

“…Aminosilane-modified silica has been extensively studied because of the wide range of applications 7) . However, it is difficult to modify the micropore walls of silica with aminosilane molecules due to steric hindrance 7) . Therefore, mesoporous silicas such as M41S, FSM-16, and SBA-15 are regarded as more suitable supports for surface modification with aminosilane, because they have large and uniform pores.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Carbon Dioxide on Aminosilane-modified Mesoporous Silica

Hiyoshi

Yogo

Yashima

2005

J. Jpn. Petrol. Inst.

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Aminosilane-modified mesoporous silica was prepared by grafting various aminosilanes on mesoporous silica, SBA-15, and the applicability as a novel adsorbent for CO2 capture and separation from flue gases was examined. Pore walls of SBA-15 were modified uniformly with aminosilanes by grafting and relatively high surface area and uniform pore size were retained. Adsorption capacities of CO2 in the presence of water were compared with those in the absence of water by a flow method. Adsorption capacities of aminosilane-modified SBA-15 were comparable in the presence and absence of water vapor. In particular, the adsorption capacity of (3-trimethoxysilylpropyl)diethylenetriamine SBA-15 reached 1.2 mmol g −1 in the presence of water vapor at 333 K, which is comparable to the adsorption capacity of zeolite Na-Y in the absence of water vapor. In addition, these adsorbents were completely regenerated by heating to 423 K in a He flow.

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Preface

Cited by 276 publications

References 0 publications

In Situ Spectroscopic Investigation of Molecular Structures of Highly Dispersed Vanadium Oxide on Silica under Various Conditions

In Situ Spectroscopic Investigation of Molecular Structures of Highly Dispersed Vanadium Oxide on Silica under Various Conditions

Bifunctional Solid Catalysts for the Selective Conversion of Fructose to 5-Hydroxymethylfurfural

Adsorption of Carbon Dioxide on Aminosilane-modified Mesoporous Silica

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