Ultrasound assisted template-free synthesis of Cu(OH)2 and hierarchical CuO nanowires from Cu7Cl4(OH)10·H2O

Cu(OH)₂ nanowires have been synthesized by an ultrasound assisted solution route in absence of a template, using Cu₇Cl₄(OH)₁₀·H₂O as a precursor. Hierarchical CuO nanowires were obtained by a simple solid-state thermal transformation of these Cu(OH)₂ nanowires. The products were characterized by XRD, SEM, TEM and HRTEM. The ranges of diameters and lengths of the polycrystalline CuO nanowires are ca. 20-30 nm and several micrometers, respectively. Ultrasonic time is found an important factor to morphology of the CuO products. This could be a potential efficient way for large scale fabrication of CuO nanowires with hierarchical structures. Surface photovoltage spectra of the CuO nanowires in air, NH₃ and CH₂Cl₂ atmospheres were investigated, which demonstrates it a good photoelectric gas sensing material.     

Addition of Urea or Biuret on Synthesis of Rhabdophane-Type Neodymium and Cerium Phosphates

Urea or biuret was added to the thermal synthetic system of Rhabdophane-type neodymium and cerium phosphates. The mixture of a rare earth compound, a phosphorus compound, and an additive [CO(NH₂)₂ or NH(CONH₂)₂] was heated at 150°C or 300°C for 20 hr, and the thermal products were analyzed by the XRD, FT-IR, and BET methods. H₃PO₄ and (NH₄)₂HPO₄ were used for phosphorus compounds, and for rare earth compounds, Nd₂O₃, Nd(NO₃)₃ · 6H₂O, NdCl₃ · 6H₂O, Nd₂(CO₃)₃ · 8H₂O, CeO₂, Ce(NO₃)₃ · 6H₂O, CeCl₃ · 7H₂O, and Ce₂(CO₃)₃ · 8H₂O were used. Urea and biuret worked not only as a dispersing agent but also as a reactant. By the addition of biuret, the thermal products changed from cerium oxide to Rhabdophane-type cerium phosphate in the system using CeCl₃ · 7H₂O and (NH₄)₂HPO₄. Addition of urea or biuret influenced the specific surface area of Rhabdophane-type neodymium and cerium phosphates. Furthermore, to increase the reactivity of the raw solid materials, mechanical treatment was performed. The mixture of diammonium hydrogenphosphate and a rare earth compound was ground with water and then heated. The influence of the addition of urea or biuret was also studied in these systems.     

Interaction of X-ray Amorphous Aluminum Oxide with Lithium Carbonate: Effect of the Chemical History of Aluminum Oxide

The high-temperature (950–1050°C) crystallization behavior of x-ray amorphous Al₂O₃ and its reaction with lithium carbonate in the range 500–700°C were studied using Al₂O₃ samples prepared by five different procedures: thermal decomposition of Al(NO₃)₃ · 9H₂O, Al₂(C₂O₄)₃ · nH₂O, aluminum hydroxides synthesized via Al³⁺ precipitation from aluminum nitrate and aluminum chloride solutions by a 20% excess of a concentrated NH₄OH solution, and sol–gel-prepared aluminum hydroxide. The results demonstrate that the preparation procedure has a significant effect on the crystallization behavior and solid-state reactivity of x-ray amorphous aluminum oxide.     

New transparent conductive films: FTO coated ITO

New transparent conductive films, fluorine doped tin oxide (FTO) films coated on indium-tin-oxide (ITO) films, were developed. These transparent conductive films were prepared by the spray pyrolysis deposition method at a substrate temperature of 350 °C in ITO and 400 °C in FTO. For ITO deposition, an ethanol solution of indium(III) chloride, InCl₃·4H₂O, and tin(II) chloride, SnCl₂·2H₂O [Sn/(In+Sn), 5 at.%] was sprayed on a Corning #7059 glass substrate (100×100×1.1 mm³). After the deposition, FTO films were consecutively deposited for protecting oxidation of ITO films. FTO deposition was carried out by an ethanol solution of tin(IV) chloride, SnCl₄·5H₂O within the saturated water solution of NH₄F. These new transparent conductive films achieved the lowest resistivity of 1.4×10⁻⁴ Ω cm and the optical transmittance of more than 80% in the visible range of the spectrum. The electrical resistance of these new transparent conductive films increased by less than 10% even when exposed to high temperatures of 300-600 °C for 1 h in the air.     

Low-temperature performance of Al4B2O9 nanowires

In this paper we report on the synthetic investigation of single-crystalline aluminum borate (Al₄B₂O₉) nanowires in large scale by a direct calcination of a precursor powder made of Na₂B₄O₇·10H₂O and Al (NO₃)₃·9H₂O at a low temperature of 850 °C. The nanowires, with the diameter of 20-40 nm and the length up to several micrometers, possess smooth surfaces and uniform sizes along the entire wire. The growth mechanism of the nanowires is attributed to a solid-liquid-solid process, which controls the nanowire morphology.     

Hydrothermal synthesis and characterization of Bi2O3 nanowires

An alternative two-step method has been proposed for the synthesis of Bi₂O₃ nanowires with a diameter of about 40 nm from common and cost-effective Bi(NO₃)₃·5H₂O, Na₂SO₄, and NaOH. That is, first, Bi₂O(OH)SO₄ nanowires were prepared through the precipitation reaction of Bi(NO₃)₃·5H₂O and Na₂SO₄ in distilled water under the ambient condition and second, monoclinic phase Bi₂O₃ nanowires were prepared via the hydrothermal reaction of Bi₂O(OH)SO₄ and NaOH at 120 °C for 12 h. The resultant products were characterized by X-ray diffraction, field emission scanning electron microscope, and high resolution transmission electron microscopy. In addition, the photocatalytic studies indicated that the as-synthesized Bi₂O₃ nanowires were a kind of promising photocatalyst in remediation of water polluted by some chemically stable azo dyes.     

Absorption Spectra of Some Crystalline Np(V) Compounds in the Visible Range

The elecotronic absorption spectra in the range 500-750 nm were measured for crystalline Np(V) compounds with the pentagonal-bipyramidal [NpO₂OOCH·H₂O, NpO₂OOCCH₂OH·H₂O, (NpO₂)₂(DMSO)₇·(ClO₄)₂·3H₂O, NpO₂ClO₄·4H₂O], hexagonal-bipyramidal [KNpO₂CO₃, (NpO₂)₂(NO₃)₂·5H₂O], and tetragonal-bipyramidal [NpO₂(TPPO)₄ClO₄, Cs₃NpO₂Cl₄] ligand surrounding. The symmetry of the coordination polyhedra affects the symmetry of narrow absorption bands; however, the long-wave shift of the peak of hydrated NpO₂₊ ions at 617 nm, caused by cation-cation interaction, is considerably less pronounced than the shift of the band at 981 nm.     

The synthesis and thermal behaviour of magnesium bis(phosphorodiamidate)

Magnesium bis(phosphorodiamidate) hexahydrate, Mg[PO₂(NH₂)₂]₂ · 6H₂O, was made by the wet process. The phosphorodiamidate was stable below 5° C, but it was converted to phosphoramidate, orthophosphate, and polyphosphates above 30° C in air. When the phosphorodiamidate was heated in air or in dry nitrogen at a higher temperature, it produced phosphoramidate, ortho- and polyphosphates, and polyphosphates with imino groups. The thermal products in air and in dry nitrogen finally gave Mg(PO₃)₂ associated with the following reaction at a higher temperature than about 700° C Mg[PO₂(NH₂)₂]₂·6H₂OMg(PO₃)+4NH₃+4H₂O and the product in dry nitrogen still contained 3 to 4% nitrogen.     

Physical Chemistry of Lanthanide Uranophosphates and Uranoarsenates

The heterogeneous equilibria LnCl₃ (solution in H₂O)-HP(As)UO₆·4H₂O (crystal) and HCl (solution in H₂O)-Ln[P(As)UO₆]₃·nH₂O (crystal), where Ln = La, Gd, Lu, were studied experimentally, and the standard Gibbs energiess of formation of the compounds Ln[P(As)UO₆]₃·nH₂O (Ln = La, Gd, Lu) were calculated. For the compounds La(PUO₆)₃·14H₂O and La(AsUO₆)₃·15H₂O the isobaric heat capacities in the range 80-300 K were measured calorimetrically, the enthalpies of formation at 298.15 K were determined, and the absolute entropies, entropies of formation, and Gibbs energies of formation were calculated. The results obtained from data on heterogeneous equilibria were compared with those of direct calorimetric measurements.     

Simultaneous removal of acetaldehyde,ammonia and hydrogen sulphide from air by active carbon impregnated with p-aminobenzoic acid,phosphoric acid and metal compounds

Simultaneous removal of acetaldehyde, ammonia, and hydrogen sulphide from air by the impregnated active carbon was studied at 25C. p-Aminobenzoic acid (PABA), phosphoric acid (H₃PO₄), and metal compound such as copper (II) chloride dihydrate (CuCl₂·2H₂O), copper (II) nitrate trihydrate (Cu(NO₃)₂·3H₂O), and potassium iodide (KI) were investigated as impregnation ingredients. Acetaldehyde and ammonia were simultaneously removed from air by the active carbon impregnated with PABA and H₃PO₄. The removal was found to be made mainly through chemical reaction. Acetaldehyde, ammonia, and hydrogen sulphide were simultaneously removed from air by the active carbon impregnated with PABA, H₃PO₄, and metal compound such as CuCl₂·2H₂O, Cu(NO₃)₂·3H₂O, and KI.     

Crystal Structure of Double Co(NH3)6 3 + Np(V) Malonates Co(NH3)6(NpO2C3H2O4)2A·H2O (A = OH and NO3)

X-ray diffraction analysis of Co(NH₃)₆(NpO₂C₃H₂O₄)₂NO₃·H₂O (I) and Co(NH₃)₆(NpO₂· C₃H₂O₄)₂OH·H₂O (II) showed that they consist of [NpO₂C₃H₂O₄] _n ^{n -} infinite anionic chains, [Co(NH₃)₆]^{3 +} cations, NO₃ ^- (I) and OH^- (II) anions, and molecules of crystallization water. The anionic chain structure is similar to that in the known compound Co(NH₃)₆(NpO₂C₃H₂O₄)₂C₃H₃O₄. Neptunium(V) atoms occur in hexagonal-bipyramidal environment. The coordination capacity of malonate anions is 6, and they simultaneously coordinate three neptunyl(V) cations NpO₂ ⁺ in the chain.     

Flower-like zinc oxide deposited on the film of graphene oxide and its photoluminescence

The graphene oxide films have been fabricated by simply filtering the graphene oxide solution through the micropore filter. Then the flower-like ZnO grows on the graphene layer by immersing the seed-coated graphene oxide films in the dilute growing solution containing NH₃·H₂O and Zn(NO₃)₂·6H₂O. The morphologies of the as-obtained ZnO deposited on the graphene oxide layer are characterized by using scanning electron microscope (SEM), X-ray powder diffraction (XRD) and photoluminescence (PL). The formation mechanism of the flower-like ZnO has also been investigated. The results show that the morphology of the finally-obtained ZnO is tunable by seeds, the concentration of growing solution and the reaction time.     

Behavior of Np(V) Malonates under Hydrothermal Conditions

Two new Np(V) malonates, LiNpO₂L·2H₂O and KNpO₂L, where L = CH₂(COO)₂, were synthesized, and their characteristics were studied. Similar to their chemical analogs with Na⁺, NH₄ ⁺, and Cs⁺ ions in the outer sphere, these compounds transform into well crystallized neptunyl(V) compounds of the MNpO₂CO₃·nH₂O type on heating in sealed ampules beneath the layer of the corresponding alkali metal or ammonium malonate solution at a temperature higher than 140°C. Under hydrothermal conditions (NpO₂)₂L·4H₂O is not converted to lower hydrates, and above 135°C it decomposes to form a dark gray amorphous product.     

Synthesis of Sb2O3 nanorods under hydrothermal conditions

Sb₂O₃ nanorods were successfully prepared via a mild hydrothermal route based on the reactions between SbCl₃ and NH₃·H₂O in aqueous solution at 120-180 °C for 12 h. The as-prepared Sb₂O₃ nanorods were characterized by X-ray diffraction (XRD), transmission electronic microscopy (TEM), and X-ray photoelctron spectroscopy (XPS). Results showed that NH₃·H₂O played a significant role in the formation of Sb₂O₃ nanorods. The presence of NH₃·H₂O could greatly favor the reaction progress toward the right-hand side and led to the orientation growth of Sb₂O₃ nanorods. A possible mechanism for the formation of Sb₂O₃ nanocrystallites was discussed.     

Double Np(V) Malonates with Co(NH3)6 3 + in the Outer Sphere

Light yellow crystalline products of the general formula Co(NH₃)₆(NpO₂L)₂A·xH₂O, where A = Cl, NO₃, or ClO₄, are precipitated with Co(NH₃)₆ ^{3 +} ions from weakly acidic chloride, nitrate, and perchlorate solutions of Np(V), containing up to 0.3 M CH₂(COO)₂ ^{2 -} (L^{2 -}). When only malonate ions are present in the solution, Np(V) precipitates in the form of Co(NH₃)₆(NpO₂L)₂HL·H₂O. These compounds are virtually insoluble in water and have similar X-ray patterns. Unlike oxalate and phthalate solutions, complex neptunyl(V) ion NpO₂L₂ ^{3 -} is not precipitated with Co(NH₃)₆ ^{3 +} ions from malonate media of the above composition.     

Preparation and characterization of ZnO porous plates

This article presents two main steps to prepare zinc oxide porous plates. Firstly, the precursor zinc hydroxide chloride hydrate (Zn₅(OH)₈Cl₂·H₂O) was synthesized by ZnCl₂ and ethylenediamine ((CH₂NH₂)₂). Secondly, the precursor was put into a furnace and annealed at 500 °C. And then the zinc oxide porous plates were successfully obtained. The crystal structures and the microstructures of the precursor and the final product were analyzed and compared by XRD, SEM and TEM. The specific surface area and gas adsorption isotherm of the final product were tested by Brunauer-Emmett-Teller equipment.     

Preparation and properties of HZr2P3O12 and related compounds

HZr₂P₃O₁₂ (H-form) was prepared in air at 650° C by de-ammoniation of NH₄Zr₂P₃O₁₂ (NH₄-form) in order to study properties of proton in the NaZr₂P₃O₁₂-type structure. Hydration of H-form took place at 70° C, 0.15 GPa, and the final product is (H₃O)Zr₂P₃O₁₂·O·17H₂O (H₃O-form). H- and H₃O-forms reacted with alkali chloride solutions at 25° C. Rates of the exchange reactions were studied as a function of water content of H- and H₃O-bearing compounds. The H-form showed an excellent selectivity for univalent cations in the order: ammonium < potassium < rubidium sodium, lithium.     

Hydrothermal synthesis of titanate nanowire arrays

A simple templateless synthesis strategy for titanate nanowire arrays was developed by employing hydrothermal reactions. Hydrothermal treatment of metallic titanium powder with H₂O₂ in a 10 M NaOH solution produced a new sodium titanate compound, Na₂Ti₆O₁₃·xH₂O (x ∼ 4.2), as arrays of nanowires of lengths up to 1 mm. The nanowires were characterized by using XRD, SEM, TGA, and TEM. The nanowires have exceptionally large aspect ratios of 5000 or higher, and they can form arrays over a large area of 2 × 3 cm². Investigations on the reaction products in varied conditions indicate that the array formation requires simultaneously controlled formation and crystal growth rates of the Na₂Ti₆O₁₃·xH₂O phase.     

Preparation of Crystalline Hydrates for Low-Temperature Physics

A number of crystalline hydrates, including two new compounds, RbNiCl₃ · H₂O and RbNiBr₃ · 6H₂O, were prepared through spontaneous crystallization in aqueous solutions by evaporating the solvent and were characterized by x-ray diffraction and thermal analysis. The lattice parameters of CsMnCl₃ · 2H₂O were found to depend on the CsCl : MnCl₂ ratio in the solution. It is shown that even a small (3%) amount of water sorbed by a dry mixture of NH₄Cl and MgCl₂ · 6H₂O is sufficient for carnallite formation to reach completion during long-term storage of powder compacts at room temperature.__________Translated from Neorganicheskie Materialy, Vol. 41, No. 5, 2005, pp. 611–618.Original Russian Text Copyright © 2005 by Petrov, Orekhov, Bagryanskaya, Sharvin.     

Synthesis of basic magnesium carbonate microrods with a surface of “house of cards” structure

Basic magnesium carbonate (Mg₅(CO₃)₄(OH)₂·4H₂O) microrods with a surface of “house of cards” structure have been synthesized in an aqueous solution system without using any surfactants or templates during the precipitation process. By tuning the reaction temperature, the morphology evolved from microrod to microrod with a surface of “house of cards” structure. The products were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), differential thermal analysis (DTA), thermogravimetric analysis (TG) and X-ray powder diffraction (XRD). It was found out that with the morphological transformation, their corresponding compositions also change from MgCO₃·3H₂O to Mg₅(CO₃)₄(OH)₂·4H₂O.