Synthesis and characterization of ternary compound,Mn<Subscript>2</Subscript>SnTe<Subscript>4</Subscript>

Mn₂SnTe₄ was synthesized by direct fusion using the anneal method. X-ray powder diffraction analysis indicated that this material crystallizes in the olivine-type structure, space group Pnma, Z = 4, with unit cell parameters: a = 14.020(2) Å, b = 8.147(1) Å, c = 6.607(1) Å, V = 754.7(2) ų. The Rietveld refinement converged to the figures of merit, R _p = 6.9%, R _wp = 8.5%, R _exp = 6.0%, χ² = 2.0 and S = 1.4.     

Chemical stability and antimicrobial activity of plasma sprayed bioactive Ca<Subscript>2</Subscript>ZnSi<Subscript>2</Subscript>O<Subscript>7</Subscript> coating

Calcium silicate ceramic coatings have received considerable attention in recent years due to their excellent bioactivity and bonding strength. However, their high dissolution rates limit their practical applications. In this study, zinc incorporated calcium silicate based ceramic Ca₂ZnSi₂O₇ coating was prepared on Ti-6Al-4V substrate via plasma spraying technology aiming to achieve higher chemical stability and additional antibacterial activity. Chemical stability of the coating was assessed by monitoring mass loss and ion release of the coating after immersion in the Tris–HCl buffer solution and examining pH value variation of the solution. Results showed that the chemical stability of zinc incorporated coating was improved significantly. Antimicrobial activity of the Ca₂ZnSi₂O₇ coating was evaluated, and it was found that the coating exhibited 93% antibacterial ratio against Staphylococcus aureus. In addition, in vitro bioactivity and cytocompatibility were confirmed for the Ca₂ZnSi₂O₇ coating by simulated body fluid test, MC3T3-E1 cells adhesion investigation and cytotoxicity assay.     

Synthesis and characterization of nanostructured SnO<Subscript>2</Subscript> film

Nanostructured tin dioxide (SnO₂) film was deposited on glass substrate by thermal evaporation of tin metal followed by thermal oxidation at 600 °C for 2 h. XRD investigation confirms that grown film is crystalline tetragonal rutile. The average optical transmittance of the film was as high as 90%. The optical band gap of the nanostructured SnO₂ was estimated from transmittance data and found to be 3.4 eV. The variation of electrical conductivity with temperature was investigated. The root mean square (RMS) roughness and topography of the film were investigated by atomic force microscopy and found to be 2 nm with grain size of 17 nm.     

Synthesis,crystal structure,and proton conductivity of KFe(H<Subscript>2</Subscript>P<Subscript>2</Subscript>O<Subscript>7</Subscript>)<Subscript>2</Subscript>

KFe H₂P₂O7)₂ is synthesized at 443 K in molten polyphosphoric acids containing K and Fe ions, and its crystal structure is determined: triclinic unit cell with a = 4.9974(6) Å, b = 7.4766(9) Å, c = 7.8185(9) Å, = 82.29(2)°, = 83.37(2)° , = 74.13(2)° ; Z = 1, sp. gr. P . The structure is made up of infinite ribbons formed by corner-shared PO₄ tetrahedra and FeO₆ octahedra, with the K atoms in between. Neighboring ribbons are linked by hydrogen bonds. The proton conductivity of potassium iron(III) dihydrogen diphosphate is rather low.Translated from Neorganicheskie Materialy, Vol. 41, No. 1, 2005, pp. 74–77. Original Russian Text Copyright © 2005 by Chudinova, Murashova, Ilyukhin, Tarnopolskii, Yaroslavtsev.     

Synthesis and characterization of new glasses based on Li<Subscript>2</Subscript>S-P<Subscript>2</Subscript>S<Subscript>5</Subscript>-Sb<Subscript>2</Subscript>S<Subscript>3</Subscript> system

There is great interest in sulfide glasses because of their high lithium ion conductivity. New sulfide glasses based on Li₂S-P₂S₅-Sb₂S₃ system have been synthesized by a classical quenching technique. A summary of thermal and structural characterization is presented. Electrical conductivities of the samples have been determined by Impedance Spectroscopy. The compositions of low lithium content (below 20% mol) have presented low electronic conductivities close to 10⁻⁸ S/cm at room temperature. The compositions of medium lithium content (30–50% mol) have presented mixed ionic-electronic behavior with predominant on ionic conductivity with a maximum values around 10⁻⁶ S/cm for samples up to 50% Li₂S at room temperature. Arrhenius behavior is verified between 25°C and T_g for all glasses with activation energies about 0.55–0.64 eV. A comparative study of conductivities with glasses belonging to the other chalcogenide systems has been undertaken.     

Synthesis and characterization of LiNi<Subscript>0.9</Subscript>Co<Subscript>0.1</Subscript>O<Subscript>2</Subscript> for lithium batteries

LiNi_0.9Co_0.1O₂ cathode material is prepared from LiOH·H₂O and Ni_0.9Co_0.1(OH)₂ by co-precipitation and subsequent two-stage heat treatment in flowing oxygen based on the results of thermogravimetric. The structural and electrochemical properties of the samples are characterized by means of inductively coupled plasma-atomic emission spectrometer (ICP-AES), X-ray diffraction (XRD), scanning electron microscope (SEM), cyclic voltammogram (CV) and charge–discharge studies. All the samples sintered at different temperatures have a typical layered structure with space group R3-m and good electrochemical performances. The sintering temperature has a remarkable effect on the electrochemical performance of the samples. The sample sintered at 730 °C shows the largest initial discharge capacity 191.1 mAh g⁻¹ (50 mA g⁻¹, 3.0–4.3 V) and the best cycling performance. The initial discharge capacity rises to above 200 mAh g⁻¹ with the voltage range 3.0–4.5 V.     

Synthesis of Sn<Subscript>2</Subscript>P<Subscript>2</Subscript>S<Subscript>6</Subscript>

A process that presents no explosion hazard is proposed for the preparation of tin(II) hexathiohypodiphosphate(IV) in a limited amount of air. The reaction of tin(II) sulfide with a mixture of phosphorus sulfides with the overall composition “P₄S₈” is studied, and the influence of synthesis temperature and duration on the completion of the reaction is analyzed.     

Synthesis and crystal structure CoNi<Subscript>2</Subscript>(BO<Subscript>3</Subscript>)<Subscript>2</Subscript>

A new metal orthoborate compound, cobalt dinickel orthoborate, CoNi₂(BO₃)₂ has been successfully synthesized for the first time. The title compound was synthesized by thermally-induced solid-state chemical reaction at 900°C between the initial reagents of Co(NO₃)₂ · 6H₂O, Ni(NO₃)₂ · 6H₂O and H₃BO₃ which were mixed with the mol ratio of 1: 2: 2 respectively. The obtained product was structurally characterized by X-ray powder diffraction technique. It has been found that the CoNi₂(BO₃)₂ crystallizes in the kotoite type and isostructural with the compounds having the chemical formula M₃(BO₃)₂ where M—Mg, Co and Ni. The synthesized compound belongs to the orthorhombic crystal system with the refined unit cell parameters of a = 5.419(9) Å, b = 8.352(0) Å, c = 4.478(8) Å and Z = 2. The space group was determined as Pnmn. Further characterizations by FTIR, elemental analysis and thermal analysis were also performed.     

Synthesis and crystal structure of [UO<Subscript>2</Subscript>(OH)(CO(NH<Subscript>2</Subscript>)<Subscript>2</Subscript>)<Subscript>3</Subscript>]<Subscript>2</Subscript>(ClO<Subscript>4</Subscript>)<Subscript>2</Subscript>

The complex [UO₂(OH)(CO(NH₂)₂)₃]₂(ClO₄)₂ (I) was synthesized. A single crystal X-ray diffraction study showed that compound I crystallizes in the triclinic system with the unit cell parameters a = 7.1410(2), b = 10.1097(2), c = 11.0240(4) Å, α = 104.648(1)°, β = 103.088(1)°, γ = 108.549(1)°, space group \(P\bar 1\), Z = 1, R = 0.0193. The uranium-containing structural units of the crystals are binuclear groups [UO₂(OH)· (CO(NH₂)₂)₃] ₂ ²⁺ belonging to crystal-chemical group AM²M ₃ ¹ [A = UO ₂ ²⁺ , M² = OH^?, M¹ = CO(NH₂)₂] of uranyl complexes. The crystal-chemical analysis of nonvalent interactions using the method of molecular Voronoi-Dirichlet polyhedra was performed, and the IR spectra of crystals of I were analyzed.     

Synthesis and characterization of Co-doped nano-TiO<Subscript>2</Subscript> through co-precipitation method for photocatalytic activity

The aim of this work was synthesis and investigation of various properties of Co-doped titanium dioxide nanostructures. Synthesis was conducted by the co-precipitation method using cobalt nitrate and titanium isopropoxide as a precursor, followed by thermal treatment at a temperature of 500 °C. The materials were fully characterized using several techniques (X-ray diffraction XRD, SEM, FTIR, TGA/DTA, UV–Vis diffuse reflectance DRS and photoluminescence). However, dopant has no effect on XRD pattern of the host but it can influence on the various characteristics of host such as optical and electrical properties. The scanning electron microscopy was used to detect the morphology of synthesized nanoparticles which sizes changed with the altitude in the doping concentration to 6%. FTIR spectra exhibit broad peaks where anatase phases of TiO₂ demonstrate very sharp UV–Vis band gap results showed the reduction in band gap from from 3.21 eV, for undoped TiO₂, to 2.74 eV, for Co doped 6% TiO₂. The photocatalytic activity of the samples were studied based on the degradation of methyl orange as a model compound, where the results showed that Co doped 6% TiO₂ a good photocatalytic activity.     

Synthesis and characterization of TiO<Subscript>2</Subscript>-incorporated silica foams

Titania-incorporated silica (TiO₂–SiO₂) porous materials have great applications in diverse areas. In this work, TiO₂–SiO₂ porous materials with tunable Si/Ti molar ratio (R) have been successfully prepared through a one-pot method under a near-neutral condition. With decreasing Si/Ti R, a phase transition from a macroporous foam-like structure to mesostructure is observed. The resultant TiO₂–SiO₂ porous materials possess large surface areas and high pore volumes. In addition, the titania species are homogenously dispersed in silica matrix when Si/Ti R ≥ 10. Our contribution provides a convenient method to synthesize TiO₂/SiO₂ porous materials with very large pore size, high pore volume, and relatively high titania content well dispersed in the silica wall framework.     

Synthesis and characterization of CuInS<Subscript>2</Subscript> thin film structures

CuInS₂ is a promising semiconductor material for solar cell applications. Here we use a mild solvothermal synthesis route to prepare CuInS₂ films with different thicknesses and morphologies on fluorine-doped tin oxide coated glass. The microstructure of the films is studied in detail by scanning electron microscopy and transmission electron microscopy (TEM) and associated analytical techniques. For further characterization, we apply X-ray diffraction and UV/Vis absorption spectroscopy. Two different films are synthesized using different reagent stoichiometries and thermal treatments. The thicker film (25 μm) consists of three different regions. Close to the substrate a 600 nm thick densely packed layer occurs, on which a 1 μm thick flaky structure is found. On top of this structure, microspheres are located which possess a size of about 3 μm and are composed of numerous flakes. The thinner film consists of a 200 nm thick densely packed layer and a net-like structure built of individual flakes as well. In both films, TEM reveals that the flakes are adjacent to 10 nm thin branch-like rods. Energy dispersive X-ray spectroscopy of the densely packed layers indicates a Cu-rich composition which suggests them to be a p-type semiconductor. The rods and the flakes show a stoichiometric composition. Due to its high surface area, the thinner film offers a promising morphology for solar cell applications based on the large available area for the separation of electron–hole pairs, when the material is combined with a suitable electron conductor.     

Synthesis and characterization of nanocrystalline TiO<Subscript>2</Subscript> thin films

Nanocrystalline thin films of TiO₂ have been synthesized by sol gel spin coating technique Thin films of TiO₂ annealed at 700 °C were characterized by X-ray diffraction(XRD), Atomic Force Microscopy, High resolution TEM and Scanning Electron Microscopy (SEM), The XRD shows formation of tetragonal anatase and rutile phases with lattice parameters a = 3.7837 Å and c = 9.5087 Å. The surface morphology of the TiO₂ films showed that the nanoparticles are fine with an average grain size of about 60 nm. Optical studies revealed a high absorption coefficient (10⁴ cm^?1) with a direct band gap of 3.24 eV. The films are of the n type conduction with room temperature electrical conductivity of 10^?6 (Ω cm)^?1.     

Synthesis and characterization of polythiophene-modified TiO<Subscript>2</Subscript> nanotube arrays

The highly ordered and uniform TiO₂ nanotube arrays were fabricated by anodic oxidation method and PTh(polythiophene)/TiO₂ nanotube arrays electrode were obtained by electrochemical polymerization. X-ray powder diffraction (XRD) analysis confirmed the formation of TiO₂ phase. The morphologies and optical characteristics of the TiO₂ nanotube arrays were studied by scanning electron microscope (SEM), UV-Vis absorption spectra and Raman spectra. The results demonstrate that the PTh/TiO₂ electrode could enlarge the visible light absorption region and increase the photocurrent in visible region. The modified TiO₂ electrode with light-to-electric energy conversion efficiency of 1·46%, the short-circuit current density of 4·52 mAcm^− 2, open-circuit voltage of 0·74 V and fill factor of 0·44, were obtained.     

Synthesis and characterization of pure anatase TiO<Subscript>2</Subscript> nanoparticles

Pure anatase TiO₂ nanoparticles were synthesized by microwave assisted sol–gel method and further characterized by powder X-ray diffraction (XRD), energy dispersive x-ray analysis (EDAX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV–Visible spectrophotometer, SEM images showed that TiO₂ nanoparticles were porous structure. The XRD patterns indicated that TiO₂ after annealed at 300 °C for 3 h was mainly pure anatase phase. The crystallite size was in the range of 20–25 nm, which is consistent with the results obtained from TEM images. Microwave heating offers several potential advantages over conventional heating for inducing or enhancing chemical reactions.     

Synthesis and high-temperature heat capacity of Yb<Subscript>2</Subscript>Sn<Subscript>2</Subscript>O<Subscript>7</Subscript> and Lu<Subscript>2</Subscript>Sn<Subscript>2</Subscript>O<Subscript>7</Subscript>

Yb₂Sn₂O₇ and Lu₂Sn₂O₇ have been prepared by solid-state reactions, by firing mixtures of Yb₂O₃ or Lu₂O₃ and SnO₂ at 1473 K, and the molar heat capacity of these compounds (pyrochlore structure) has been determined by differential scanning calorimetry. The C _p (T) data have been used to evaluate the thermodynamic properties of the stannates: enthalpy increment, entropy change, and reduced Gibbs energy.     

Synthesis,structure, and thermal expansion of M<Subscript>2</Subscript>Fe<Subscript>2</Subscript>Ti<Subscript>6</Subscript>O<Subscript>16</Subscript> and MFeTiO<Subscript>4</Subscript> compounds

Compounds that crystallize in four structure types in M₂O-Fe₂O₃-TiO₂ systems have been prepared by solid-state reactions. The M₂Fe₂Ti₆O₁₆ (M = Rb, Cs) compounds have been prepared for the first time. The thermal expansion coefficients of the MFeTiO₄ (M = Li, Na) and M₂Fe₂Ti₆O₁₆ (M = Na, K, Rb, Cs) compounds have been determined by high-temperature X-ray diffraction.     

Synthesis and High-Temperature Heat Capacity of Sm<Subscript>2</Subscript>Ge<Subscript>2</Subscript>O<Subscript>7</Subscript> and Eu<Subscript>2</Subscript>Ge<Subscript>2</Subscript>O<Subscript>7</Subscript>

The Sm₂Ge₂O₇ and Eu₂Ge₂O₇ germanates have been prepared by solid-state reactions via multistep firing of stoichiometric mixtures of Sm₂O₃ (Eu₂O₃) and GeO₂ in air at temperatures from 1273 to 1473 K. The molar heat capacity of the samarium and europium germanates has been determined by differential scanning calorimetry in the range 350–1000 K and the C _p (T) data have been used to evaluate their thermodynamic properties.     

Synthesis and High-Temperature Heat Capacity of Dy<Subscript>2</Subscript>Ge<Subscript>2</Subscript>O<Subscript>7</Subscript> and Ho<Subscript>2</Subscript>Ge<Subscript>2</Subscript>O<Subscript>7</Subscript>

The Dy₂Ge₂O₇ and Ho₂Ge₂O₇ pyrogermanates have been prepared by solid-state reactions in several sequential firing steps in the temperature range 1237–1473 K using stoichiometric mixtures of Dy₂O₃ (or Ho₂O₃) and GeO₂. The heat capacity of the synthesized germanates has been determined as a function of temperature by differential scanning calorimetry in the range 350–1000 K. The experimentally determined C _p (T) curves of the dysprosium and holmium germanates have no anomalies and are well represented by the Maier–Kelley equation. The experimental C _p (T) data have been used to evaluate the thermodynamic functions of the Dy₂Ge₂O₇ and Ho₂Ge₂O₇ pyrogermanates: enthalpy increment H°(T)–H°(350 K), entropy change S°(T)–S°(350 K), and reduced Gibbs energy Ф°(T).     

Synthesis,microstructure, and gas-sensing properties of SnO<Subscript>2</Subscript>/MoO<Subscript>3</Subscript> nanocomposites

SnO₂/MoO₃ nanocomposites are synthesized in a broad composition range through chemical precipitation from solution, and their phase composition and microstructure are investigated by x-ray diffraction. The gas sensitivity of the nanocomposites to lower alcohols (C_nH_{2n + 1} OH, n=1–4) is studied by in situ conductance measurements. The results are interpreted in terms of the acid-base properties of the nanocomposite surface.__________Translated from Neorganicheskie Materialy, Vol. 41, No. 4, 2005, pp. 442–449.Original Russian Text Copyright © 2005 by Makeeva, Rumyantseva, Gaskov.