Facile synthesis of freestanding Si nanowire arrays by one-step template-free electro-deoxidation of SiO2 in a molten salt.

This communication presents a novel kind of silicon nanomaterial: freestanding Si nanowire arrays (Si NWAs), which are synthesized facilely by one-step template-free electro-deoxidation of SiO2 in molten CaCl2. The self-assembling growth process of this material is also investigated preliminarily.

Sputtered highly ordered TiO2 nanorod arrays and their applications as the electrode in dye-sensitized solar cells.

For the first time, the TiO2 nanorod arrays have been prepared on ITO substrates at room temperature by dc reactive magnetron sputtering technique. These TiO2 nanorods have a preferred orientation along the (220) direction and are perpendicular to the ITO substrate. Both the X-ray diffraction and Raman scattering measurements show that the highly ordered TiO2 nanorod arrays have an anatase crystal structure.

From molecular fragments to crystals: a UV Raman spectroscopic study on the mechanism of Fe-ZSM-5 synthesis.

The nucleation process of iron-exchanged zeolite Fe-ZSM-5, from the assembly of distorted tetrahedrally coordinated iron species and silicate rings in the precursor to the final Fe-ZSM-5 crystals, as well as variations in the coordination environment of iron, were studied by UV resonance Raman spectroscopy and complementary techniques.The entire sequence of crystallization events of Fe-ZSM-5 was monitored by UV Raman spectroscopy in combination with HRTEM, UV/Vis spectroscopy, X-ray diffraction patterns, and periodic DFT calculations. Fe-ZSM-5 was synthesized by an organic-free method to avoid signal interference from the organic template in Raman spectra.

Crystallization of metastable beta glycine from gas phase via the sublimation of alpha or gamma form in vacuum.

It is found that beta glycine, the metastable polymorph of glycine, can be rapidly formed from gas phase via the sublimation of its stable alpha or gamma form in vacuum. The transformation process was monitored by infrared spectroscopy and the crystal structure of the sublimate was identified by X-ray diffraction techniques. It is the first report about the transformation of stable alpha or gamma glycine into metastable beta form in "one-step" (heating then cool down spontaneously).

Time-resolved photoluminescence characteristics of subnanometer ZnO clusters confined in the micropores of zeolites.

Subnanometric ZnO clusters confined in different micropore zeolites are studied by steady-state and nanosecond time-resolved photoluminescence (PL) spectroscopy. The microsecond-scale lifetime is observed at room temperature for ZnO clusters confined in zeolites, which is significantly different from that of macrocrystalline ZnO on the external surface of zeolites. The dependence of luminescence lifetime on the amount of ZnO in zeolites indicates that the electron-phonon interactions between the ZnO clusters and the zeolite host significantly affect the dynamic relaxation process of ZnO clusters.

The study of thiophene adsorption onto La(III)-exchanged zeolite NaY by FT-IR spectroscopy.

Zeolites NaY and LaNaY (ion-exchanged with aqueous lanthanum nitrate solution) were used as adsorbents for removing organic sulfur compounds from model gasoline solutions (without and with toluene) and fluid catalytic cracked gasoline in fixed-bed adsorption equipment at room temperature and atmosphere pressure. The adsorptive selectivity for organic sulfur compounds was significantly increased when Na(+) ions in zeolite NaY were exchanged with lanthanum ions. IR spectra of thiophene adsorption indicate that thiophene is adsorbed onto La(3+) ions via direct S-La(3+) interaction and Na(+) ions via pi-electronic interaction for La(3+)-exchanged zeolite NaY, but only via pi-electronic interaction with Na(+) ions for NaY.

Dibenzodioxin adsorption on inorganic materials.

Dibenzodioxin adsorption/desorption on solid surfaces is an important issue associated with the formation, adsorption, and emission of dioxins. Dibenzodioxin adsorption/desorption behaviors on inorganic materials (amorphous/mesoporous silica, metal oxides, and zeolites) were investigated using in situ FT-IR spectroscopy and thermogravimetric (TG) analysis. Desorption temperatures of adsorbed dibenzodioxin are very different for different kinds of inorganic materials: approximately 200 degrees C for amorphous/mesoporous silica, approximately 230 degrees C for metal oxides, and approximately 450 degrees C for NaY and mordenite zeolites.

Enhancement of alpha-oxygen formation and N2O decomposition on Fe/ZSM-5 catalysts by extraframework Al.

The concentration of alpha-oxygen which can oxidize methane to methanol and benzene to phenol at RT, increases linearly with the amount of introduced extraframework Al on Fe/ZSM-5 catalysts prepared by solid-state exchange of FeCl3 and AlCl3 with H-ZSM-5.

Ultra-deep desulfurization of diesel: oxidation with a recoverable catalyst assembled in emulsion.

A [(C(18)H(37))(2)N(+)(CH(3))(2)](3)[PW(12)O(40)] catalyst, assembled in an emulsion in diesel, can selectively oxidize the sulfur-containing molecules present in diesel into their corresponding sulfones by using H(2)O(2) as the oxidant under mild conditions. The sulfones can be readily separated from the diesel using an extractant, and the sulfur level of the desulfurized diesel can be lowered from about 500 ppm to 0.1 ppm without changing the properties of the diesel.

In Situ FT-IR Spectroscopic Studies of CO Adsorption on Fresh Mo2C/Al2O3 Catalyst.

The surface sites of supported molybdenum carbide catalyst derived from different synthesis stages have been studied by in situ FT-IR spectroscopy using CO as the probe molecule. Adsorbed CO on the reduced passivated Mo2C/Al2O3 catalyst gives a main band at 2180 cm(-1), which can be assigned to linearly adsorbed CO on Mo(4+) sites. The IR results show that the surface of reduced passivated sample is dominated by molybdenum oxycarbide.

A novel catalyst for hydrazine decomposition: molybdenum carbide support on gamma-Al2O3.

An alumina-supported Mo2C catalyst is found to be as active as a conventionally used Ir/gamma-Al2O3 catalyst for catalytic decomposition of hydrazine tested in a monopropellant thruster.