Structure of the microporous titanosilicate ETS-10

Anderson, Michael W.; Terasaki, Osamu; Ohsuna, Tetsu; Philippou, Andreas; Mackay, Simon P.; Ferreira, Artur; Rocha, João; Lidin, Sven

doi:10.1038/367347a0

Cited by 575 publications

(404 citation statements)

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“…The structure of ETS-10 comprises corner-sharing SiO 4 tetrahedra and TiO 6 octahedra linked through bridging oxygens. 33 In the bimetallic Co-ETS-10 sieve, the cobalt centers were found to isomorphically substitute Si sites adjacent to TiO 6 octahedra based on EXAFS evidence. 23 A visible absorption tail extending beyond 500 nm is observed, which is not present in monometallic ETS-10.…”

Section: Binuclear Tioco Sites In Mcm-41mentioning

confidence: 99%

Visible light absorption of binuclear TiOCoII charge-transfer unit assembled in mesoporous silica

Han

Frei

2007

Microporous and Mesoporous Materials

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Section: Binuclear Tioco Sites In Mcm-41mentioning

confidence: 99%

Visible light absorption of binuclear TiOCoII charge-transfer unit assembled in mesoporous silica

Han

Frei

2007

Microporous and Mesoporous Materials

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“…In ETS-10, one identifies octahedral Ti 4+ ions besides tetrahedral framework Si 4+ ions. 9 Each [TiO 6 ] lattice unit bears two negative charges, which are usually balanced by exchangeable Na + and K + ions. Adsorption of small probe molecules in combination with vibrational spectroscopy is a widely used technique to study the acid−base properties of active sites in heterogeneous catalysts.…”

Section: Introductionmentioning

confidence: 99%

Structure and Basicity of Microporous Titanosilicate ETS-10 and Vanadium-Containing ETS-10

et al. 2012

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ETS-10 has attracted considerable attention as a base catalyst. It is desirable to confirm the location of basic sites. Vanadium-substituted ETS-10 also attracts much attention for the interesting feature that the Ti can be fully replaced by V without changing its topology. It is important to characterize the local environment upon V substitution for understanding the property and reactivity of ETVS-10. The structural and acid−base properties of pure titanosilicate ETS-10 and a series of vanadium-substituted ETVS-10 with different framework V content were studied by a combination of Raman spectroscopy and FTIR of absorbed acetylene and carbon monoxide as molecular probes. The substitution of up to 70% of Ti atoms with V in the structure of ETS-10 results in ETVS-10 materials with a homogeneous distribution of Ti and V species. At higher V concentrations, a distinct phase separation between the vanadium-rich domains is observed. The intrinsic basicity of ETVS-10 as revealed by FTIR spectroscopy of adsorbed C 2 H 2 gradually increases with the increasing V content. It is shown that the specific basicity of the ETS-10 lattice is mainly associated with the presence of highly basic oxygen centers adjacent to the lattice defects. Liquid phase Knoevenagel condensation of benzaldehyde with ethyl cyanoacetate was used as a test reaction to investigate the catalytic reactivity of different basic sites in the synthesized materials. The reactivity of the materials considered in the base-catalyzed Knoevenagel condensation is determined not only by the strength of the basic sites but also by their density. The optimum combination of both factors is achieved for the ETVS-10 material with V/(Ti+V) ratio of 70%.

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“…Although a number of bulk titanosilicates are known (e.g. ETS-10 [58]), in all such materials the stoichiometry is such that it is effectively oxygen deficient with respect to a composition of the type (TiO 2 ) N (SiO 2 ) M . At the cluster scale, however, the mixing energies for the ternary oxides are succinctly different from the bulk.…”

Section: Results (A) Bulk and Cluster Mixing Of Binary Oxidesmentioning

confidence: 99%

Stardust silicate nucleation kick-started by SiO+TiO ₂

Goumans

Bromley

2013

Phil. Trans. R. Soc. A.

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Dust particles are quintessential for the chemical evolution of the Universe. Dust nucleates in stellar outflows of dying stars and subsequently travels through the interstellar medium, continuously evolving via energetic processing, collisions and condensation. Finally, dust particles are incorporated in the next-generation star or its surrounding planetary system. In oxygen-rich stellar outflows, silicates are observed in the condensation zone (1200–1000 K), but, in spite of several decades of experimental and theoretical study, the stardust nucleation process remains poorly understood. We have previously shown that under these conditions ternary Mg–Si–O clusters may start forming at high enough rates from SiO, Mg and H 2 O through heteromolecular association processes. In this reaction scheme, none of the possible initial association reactions was thermodynamically favourable owing to the large entropy loss at these temperatures. Here, we follow a previous idea that the incorporation of TiO 2 could help to initiate stardust nucleation. In contrast to these studies, we find that there is no need for TiO 2 cluster seeds—instead, one molecule of TiO 2 is sufficient to kick-start the subsequent nucleation of a silicate dust particle.

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Structure of the microporous titanosilicate ETS-10

Cited by 575 publications

References 4 publications

Visible light absorption of binuclear TiOCoII charge-transfer unit assembled in mesoporous silica

Visible light absorption of binuclear TiOCoII charge-transfer unit assembled in mesoporous silica

Structure and Basicity of Microporous Titanosilicate ETS-10 and Vanadium-Containing ETS-10

Stardust silicate nucleation kick-started by SiO+TiO ₂

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Structure of the microporous titanosilicate ETS-10

Cited by 575 publications

References 4 publications

Visible light absorption of binuclear TiOCoII charge-transfer unit assembled in mesoporous silica

Visible light absorption of binuclear TiOCoII charge-transfer unit assembled in mesoporous silica

Structure and Basicity of Microporous Titanosilicate ETS-10 and Vanadium-Containing ETS-10

Stardust silicate nucleation kick-started by SiO+TiO 2

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Stardust silicate nucleation kick-started by SiO+TiO ₂