Hydrothermal synthesis of one-dimensional (1D) Na<Subscript>x</Subscript>TiO<Subscript>2</Subscript> nanostructures

Nanorods of sodium titanium dioxide bronze Na_xTiO₂ were synthesized by the hydrothermal treatment of the amorphous TiO₂·nH₂O gel with 10 M NaOH followed by ultrasonication in 0.1 M HCl and thermal treatment (500°C, 10 h). The thermal treatment of the nanorods does not change the morphology of the particles. According to the electron diffraction data, the Na_xTiO₂ nanorods grow along the c axis.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 71–73, January, 2005.     

Structural, textural, and electronic properties of a nanosized mesoporous ZnxTi1-xO2-) solid solution prepared by a supercritical drying route

Mesoporous nanosized TiO2 and Zn(x)Ti(1-x)O(2-x) solid solution having a Zn content below 10 mol % with a particles size between 13 and 17 nm are prepared by a template-free sol-gel method followed by high-temperature supercritical drying in 2-propanol. The structural, textural, and electronic properties of the obtained nanomaterials are methodically investigated by using XRD, SEM, TEM, ED, HREM, EDX, ICP-OES, N(2) adsorption-desorption, Raman spectroscopy, and diffuse reflectance UV-vis spectroscopy. It is shown that the proposed synthesis technique leads to the formation of a Zn(x)Ti(1-x)O(2-x) solid solution based on the anatase crystal structure rather than a two-phase sample. High-resolution electron microscopy and electron diffraction indicate that the distribution of zinc atoms over the anatase structure does not lead to a considerable deformation of the crystal structure.     

Search for inert oxide matrices for carrying out solid-phase ion-exchange reactions by the internal reaction scheme

Having a goal of studying the possibility of and develop methods for controlling internal solidphase reactions inside a solid matrix that is diffusionally saturated with several components simultaneously from different source phases, we experimentally checked whether it is possible to synthesize, for use as these matrices, ZrO₂-Nb₂O₅ solid solutions having distorted fluorite structure and NiO-CuO-Cu₂O solid solutions having rock salt structure (these solid solutions had been studied by computational techniques using the ion lattice mechanic approximation), with a controlled ratio of anionic and cationic conductivities.     

Preparation of reagent indicator papers with silver triangular nanoplates for chemical analysis

An impregnation method to prepare reagent indicator papers with silver triangular nanoplates (TNPs) is developed. The conditions for obtaining modified papers (type of paper, method for applying TNPs, and drying conditions) allowing for an acceptably uniform distribution of the TNPs are chosen. The spectral characteristics of the prepared materials are studied. The presence of an intense TNP surface plasmon resonance band in the diffuse reflectance spectra of the modified papers, which is linearly related to the content of the TNPs in the samples, as well as the lability of its position and shape in the presence of some substances, gives rise to the prospects of using the prepared materials as test-tools in chemical analysis.     

Estimation of the possibility of internal solid-phase reactions to occur in some oxide systems

We calculated the energy of defect formation and the mobility of defects in cubic ZrO₂-based solid solutions and in nickel and cadmium oxides in a view of developing methods for controlling internal solidphase reacitons in an inert matrix, these reactions being of considerable importance for manufacturing matrix/inclusion composites. The calculations were carried out for an ionic model of chemical bond using GULP software. The frequency factors in the Arrhenius temperature funcitons of diffusion coefficients were estimated for various cationic and anionic defects using circular vibration frequencies of hopping atoms. A frequency factor was estimated as the mean vibration frequency obtained from lattice dynamic calculations also using GULP software followed by the Fourier-transform analysis of the projection of the trajectory of an atom on the direction of transition into an activated state. The results were used to estimate the excess anion concentrations necessary for reaching equal cationic and anionic mobilities at various temperatures; from these estimations, it was inferred that, of the systems under consideration, an internal solid-phase reaction is expected to occur only for NiO.