The direct synthesis of crystalline titania nanorods by sol-gel chemistry in a special ionic liquid is reported. Unexpectedly, the high-temperature modification, rutile, is obtained directly under ambient conditions. X-ray diffraction and high-resolution transmission electron microscopy measurements support the highly crystalline and structural quality of the sample. The phase-directing property of the ionic liquids is attributable to the imide group in the counter ion, which exhibits strong interaction with specific rutile faces. Lithium insertion experiments were performed and revealed high and reversible loading capacities of up to 200 mAh g(-1).
Platinum nanoparticles
dispersed on nanosized ceria are active
for CO oxidation at room temperature after hydrogen pretreatment.
High angular annular dark field scanning transmission electron microscopy
(HAADF-STEM) analysis of the reduced catalyst shows spreading of the
1 nm sized platinum particles under the electron beam, characteristic
for a two-dimensional strong metal–support interaction. In
situ X-ray absorption fluorescence spectroscopy (XAFS) reveals a Pt–O
distance of 2.1 Å, which is significantly longer than the Pt–O
distance in PtO2 (2.0 Å). This elongated Pt–O
distance can be related to interaction of the platinum species with
cerium oxide in the form of a low-temperature active species–support
interaction. These findings contribute to the general understanding
of catalytic systems operating at low temperature.
The long-chain ionic liquid (IL) 1-hexadecyl-3-methylimidazolium chloride (C(16)mimCl) was used as a template to prepare porous silica with a two-dimensional hexagonal p6mm mesopore structure (MCM-41-type) as well as with a cubic Ia3d (gyroid, MCM-48-type structure) framework in basic synthesis medium via a hydrothermal synthesis procedure. A systematic study was carried out addressing the influence of the relative concentration of the IL and the pH on the mesostructure. As a main result, the IL template shows a broad range of conditions that allow the synthesis of the gyroid mesostructure with improved reproducibility. Unexpectedly, the formation of the hexagonal phase is less favorable, as the latter is quite sensitive to variations in parameters. This preference for the bicontinuous structure can be attributed to the special headgroup packing of ILs containing imidazolium groups.
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