RADIATION STIMULATION OF THE CATALYTIC ACTIVITY OF ZIRCONIUM DIOXIDE NANOPARTICLES DURING THE CONVERSION OF HYDROCARBONS

The comparison of the catalytic activity of the initial and activated by bremsstrahlung -radiation on a high-current electron accelerator of zirconium dioxide nanoparticles on the nature of the conversion of ethanol. The used -activation parameters contributed to the formation of a more perfect crystal structure of ZrO2 nanoparticles. It was shown that when using -activated ZrO2 nanoparticles as a catalyst, the yield of hydrocarbon products during the conversion of ethanol was several times higher than the yield of the same products in the case of using the initial ZrO2 nanoparticles. The mechanism of such a conversion of ethanol can be associated with the synergism of large ionization losses of Auger electrons and the effect of highly reactive products involved in heterogeneous catalysis.

Comparative Analysis of Physicochemical Properties of Rutile TiO2 with Hierarchical 3D Architecture Prepared by Liquid Hydrolysis of TiCl4 and Hydrothermal Method

TiO2 (rutile) samples with a hierarchical 3D nanostructure of the particles were synthesized by two methods: liquid hydrolysis of TiCl4 at 90 °С and atmospheric pressure; hydrothermal synthesis from TiCl4 at 160 °С and different [H2O]/[Ti] ratios. The effect exerted by conditions of the synthesis and post-treatments on the crystallite size, morphology, electronic properties and pore structure of the rutile samples was investigated. It was shown that severe hydrothermal conditions with the ratio [H2O]/[Ti] = 20 provide the formation of a more perfect crystal structure of rutile with a smaller band gap energy (3.00 eV against 3.06 eV for the rutile obtained by liquid hydrolysis at atmospheric pressure). The study revealed the stabilizing effect of cerium cations on the pore structure of rutile, which changes upon thermal treatment.

Unique CoS hierarchitectures for high-performance lithium ion batteries

Lantern-like CoS hierarchitectures, having a perfect crystal structure, a high specific surface area and lots of nanoscale 3D channels, are synthesized.

Synthesis, Characterization and Electrochemistry of Cathode Material Li [Li0.2Mn0.54Ni0.13Co0.13]O2 Nanofibers Prepared by Electrospinning for Lithium Ion Batteries

Nanofibers of Li [Li0.2Mn0.54Ni0.13Co0.13]O2with high crystallinity were easily synthesized by electrospinning. Scanning electron microscopy (SEM) showed that precursor wires were glossy, and the diameters of oxide calcined at 800°C were 50-200 nm. And X-ray diffraction (XRD) exhibited perfect crystal structure. The electrochemical properties of materials with the specific morphology were significantly improved. The first charge/discharge capacity was around 309.3 and 270.2 mAh·g-1at 25 mA·g-1, and the first coulomb efficiency (87.4%) represented a good efficiency for Li2MnO3-type electrodes. After 20 cycles, discharge capacity was over 200 mAh·g-1at 25 mA·g-1, and capacity retention was 79.8% at 250 mA·g-1.Owing to its simplicity and applicability, the electrospinning method is an promising method to fabricate high performance Li [Li0.2Mn0.54Ni0.13Co0.13]O2materials for lithium ion batteries.

Study on Structures and Properties of CaSO4 Whiskers/PVC Composites

Structures of CaSO4 whisker(A) and CaSO4 whisker(B) were characterized by IR and XRD, and the morphologies were observed by optical microscope. The results showed that the modified CaSO4 whisker(B) has perfect crystal structure, high crystallinity and less defects. Mechanical properties and static thermal stability time(190 °C) of two composites which were prepared by CaSO4 whisker(A) / PVC and CaSO4 whisker(B) / PVC were tested separately, and the degradation processes were analyzed by TG at 50 °C-400°C, N2 atmosphere, and the dispersing states of two whiskers in the composites were observed by means of optical microscope and SEM. The research results showed that the tensile strength and elongation at break increased over 3 MPa and 40% separately, and the static thermal stability time was over 90 min of CaSO4 whisker(B) / PVC, the initial degradation time was delayed comparing with CaCO3 / PVC composite. The consistency and interfacial configuration between whisker and PVC resin were perfect, and the toughness and thermal stability of the composite was improved after CaSO4 whisker was modified. The research results indicated that modified CaSO4 whisker has better toughness and thermal stability actions for PVC.

Influence of Mineralogical Origin of Limestone Powder on the Performance of Complex Binder Material

The effect of mineralogical origin, elemental component, crystal structure of three types of limestone powder on the fluidity of cement-limestone paste and mortar was investigated. The results show that the limestone powder originated from the mine of limestone and river pebble have better water-reducing effect, which is closely correlated with the main components of Calcite and Dolomite. These two mineral have relatively regular, orderly and perfect crystal structure with few defects and unfilled pores which are liable to adsorb more water and water-reducing agents. On the contrary, the limestone powder derived from the mine of sandstone has nearly no water-reducing effect which is ascribed to the large amount of clay mineral which exhibit lamellar structure leading to the large quantity of consumption of water.

Preparation and Characterization of La0.9Sr0.1Co0.5Mn0.5O3 Composite Catalytic Materials for Conversion of Exhaust Gas from Natural Gas Automobiles

A series of rare earth perovskite-type oxides La0.9Sr0.1CoO3, La0.9Sr0.1MnO3 and La0.9Sr0.1Co0.5Mn0.5O3 were prepared by sol-gel method and characterized by X-ray diffraction (XRD), specific surface analysis (BET), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) techniques. The results showed that for La0.9Sr0.1Co0.5Mn0.5O3 sample, Sr2+ and Mn3+ ions partly replaced La3+ and Co3+ ions and entered perovskite crystal lattice, and finally a perfect crystal structure of perovskite was formed. Moreover, these powders presented sphericity granules with particle size of about 20nm and satisfactory pore structure. With the doping of Sr2+ ions in a certain range, the coexisting system of Mn3+- Mn4+ and Co3+- Co4+ as well as the concentration of oxygen vacancies were increased, thus leading to the higher catalytic activity of the prepared catalysts.

5.10 Are Interplanetary Grains Crystalline?

The optical properties of interplanetary grains depend not only on chemical composition, size, and shape but also on lattice defects. It is argued that practically all sources for the zodiacal dust cloud yield grains with highly disturbed crystal structure. Healing of these defects can occur when the grains are heated in the vicinity of the sun (≤0.1 AU) and various orbits are considered, on which annealed grains with nearly perfect crystal structure can return to larger heliocentric distances to reveal the sharp optical features of cold well-ordered crystals. However, we do not find any processes, which produce healed particles of sufficient number to affect the properties of the general zodiacal cloud. Therefore, the optical properties of interplanetary grains are determined by a high degree of lattice perturbation.