The synthesis of bayberry-like mesoporous TiO2 microspheres by a kinetics-controlled method and their hydrophilic films

ABSTRACTDoping Rare-earth (RE) elements to ZrO2 helps stabilize the cubic and tetragonal phases and improves resistance to thermal shock and sintering at high temperatures. Since a RE ion has a lower valency (3+) than Zr ion (4+), oxygen vacancies are formed to preserve electroneutrality. We have studied the crystal structure of La0.1Zro.9O1.95 and Nd0.1Zr0.9O1.95 by neutron diffraction and examined the associated oxygen defects by a Fourier transform of the filtered residual diffuse scattering. The hydration process was investigated by inelastic neutron-scattering measurements of the hydrogen vibrational density of states of the surface hydroxyl groups and physisorbed water on these fine powders. We compare the O-H stretch vibrations from samples with only surface hydroxyl groups to multilayer coverage of water molecules. The decreasing energies and increasing widths of the O-H stretch bands with increasing H2O coverage indicate the influence of hydrogen bonding on the motion of water molecules. Similar elastic and inelastic experiments were also performed on a high surface-area pure ZrO2 powder.

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Silica microspheres containing high density surface hydroxyl groups as efficient epoxidation catalysts

RSC Advances ◽

10.1039/c5ra00374a ◽

2015 ◽

Vol 5 (27) ◽

pp. 21125-21131 ◽

Cited By ~ 8

Author(s):

Prakash Chandra ◽

Dhananjay S. Doke ◽

Shubhangi B. Umbarkar ◽

Kumar Vanka ◽

Ankush V. Biradar

Keyword(s):

Hydrogen Peroxide ◽

High Density ◽

Hydroxyl Groups ◽

Silica Microspheres ◽

Surface Hydroxyl ◽

Condensation Method ◽

Surface Hydroxyl Groups ◽

Density Surface

Uniformly sized silica microspheres were synthesized by a hydrolysis–condensation method and very efficient for epoxidation of olefine using hydrogen peroxide as green oxidant.

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Interior surface hydroxyl groups in ordered mesoporous silicates

Solid State Ionics ◽

10.1016/s0167-2738(97)00189-6 ◽

1997 ◽

Vol 101-103 (1-2) ◽

pp. 271-277 ◽

Cited By ~ 60

Author(s):

H Landmesser

Keyword(s):

Hydroxyl Groups ◽

Mesoporous Silicates ◽

Interior Surface ◽

Surface Hydroxyl ◽

Surface Hydroxyl Groups ◽

Ordered Mesoporous

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The synthesis and structure of silica-supported bis(h5-cyclopentadienyl)dichlorotitanium(IV) complexes

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19861430 ◽

1986 ◽

Vol 51 (7) ◽

pp. 1430-1438 ◽

Cited By ~ 6

Author(s):

Alena Reissová ◽

Zdeněk Bastl ◽

Martin Čapka

Keyword(s):

Free Surface ◽

Hydroxyl Groups ◽

Titanium Complex ◽

Surface Hydroxyl ◽

Surface Hydroxyl Groups ◽

Free Hydroxyl ◽

Cyclopentadienyl Anion

The title complexes have been obtained by functionalization of silica with cyclopentadienylsilanes of the type Rx(CH3)3 - xSi(CH2)nC5H5 (x = 1-3, n = 0, 1, 3), trimethylsilylation of free surface hydroxyl groups, transformation of the bonded cyclopentadienyl group to the cyclopentadienyl anion, followed by coordination of (h5-cyclopentadienyl)trichlorotitanium. The effects of single steps of the above immobilization on texture of the support, the number of free hydroxyl groups, the coverage of the surface by cyclopentadienyl groups and the degree of their utilization in anchoring the titanium complex have been investigated. ESCA study has shown that the above anchoring leads to formation of the silica-supported bis(h5-cyclopentadienyl)dichlorotitanium(IV) complex.

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