Center Dot 2H Research Articles

Comparison of Rietveld-compatible structureless fitting analysis methods for accurate quantification of carbon dioxide fixation in ultramafic mine tailings

The carbonation of ultramafic rocks, including tailings from ultramafic-hosted ore deposits, can be used to remove CO2 from the atmosphere and store it safely within minerals over geologic timescales. Quantitative X-ray diffraction (XRD) using Rietveld refinements can be employed to estimate the amount of carbon sequestered by carbonate minerals that form as a result of weathering of ultramafic rocks. However, the presence of structurally disordered phases such as serpentine minerals, which are common in ultramafic ore bodies such as at the Woodsreef chrysotile mine (New South Wales, Australia), results in samples that cannot be analyzed using typical Rietveld refinement strategies. Previous investigations of carbon sequestration at Woodsreef and other ultramafic mine sites typically used modified Rietveld refinement methods that apply structureless pattern fitting for disordered phases; however, no detailed comparison of the accuracy (or precision) of these methods for carbon accounting has yet been attempted, making it difficult to determine the most appropriate analysis method. Such an analysis would need to test whether some methods more accurately quantify the abundances of certain minerals, such as pyroaurite [Mg6Fe23+(CO3)(OH)(16)center dot 4H(2)O] and other hydrotalcite group minerals, which suffer from severe preferred orientation and may play an important role in carbon sequestration at some mines. Here, we assess and compare the accuracy, and to a lesser extent the precision, of three different non-traditional Rietveld refinement methods for carbon accounting: (1) the PONKCS method, (2) the combined use of a Pawley fit for serpentine minerals and an internal standard (Pawley/internal standard method), and (3) the combined use of PONKCS and Pawley/internal standard methods. We examine which of these approaches represents the most accurate way to quantify the abundances of serpentine, pyroaurite, and other carbonate-bearing phases in a given sample. We demonstrate that by combining the PONKCS and Pawley/internal standard methods it is possible to quantify the abundances of disordered phases in a sample and to obtain an estimate of the amorphous content and any unaccounted intensity in an XRD pattern. Eight artificial tailings samples with known mineralogical compositions were prepared to reflect the natural variation found within the tailings at the Woodsreef chrysotile mine. Rietveld refinement results for the three methods were compared with the known compositions of each sample to calculate absolute and relative error values and to evaluate the accuracy of the three methods, including whether they produce systematic under- or overestimates of mineral abundance. Estimated standard deviations were also calculated during refinements; these values, which are a measure of precision, were not strongly affected by the choice of refinement method. The abundance of serpentine minerals is, however, systematically overestimated when using the PONKCS and Pawley/internal standard methods, and the abundances of minor phases (<10 wt%) are systematically underestimated using all three methods. Refined abundances for pyroaurite were found to be increasingly susceptible to error with increasing abundance, with an underestimation of 6.6 wt% absolute (60.6% relative) for a sample containing 10 9 wt% pyroaurite.These significant errors are due to difficulties in mitigating preferred orientation of hydrotalcite minerals during sample preparation as well as modeling its effects on XRD patterns. The abundances of hydromagnesite [Mg,(CO3)(4)(OH)(2)center dot 4H(2)O], another important host for atmospheric CO2 during weathering of ultramafic rocks, was consistently underestimated by all three methods, with the highest underestimation being 3.7 wt% absolute (or 25.0% relative) for a sample containing 15.0 wt% hydromagnesite. Overall, the Pawley/internal standard method produced more accurate results than the PONKCS method, with an average bias per refinement of 6.7 wt%, compared with 10.3 wt% using PONKCS and 12.9 wt% for the combined PONKCS-Pawley/internal standard method. Furthermore, the values for the refined abundance of hydromagnesite obtained from refinements using the Pawley/internal standard method were significantly more accurate than those for refinements done with the PONKCS method, with relative errors typically <25% for hydromagnesite abundances between 5 and 15 wt%. The simpler and faster sample preparation makes the PONKCS method well-suited for rapid carbon accounting, for instance in the field using a portable XRD; however, the superior accuracy gained when using an internal standard make the Pawley/internal standard method the preferable means of undertaking a detailed laboratory-based study. As all three methods displayed an underestimation of carbonate phases, applying these methods to natural samples will likely produce an underestimate of hydromagnesite and hydrotalcite group mineral abundances. As such, crystallographic accounting strategies that use modified Rietveld refinement methods produce a conservative estimate of the carbon sequestered in minerals.

Alpine halite-mudstone-polyhalite tectonite: Sedimentology and early diagenesis of evaporites in an ancient rift setting (Haselgebirge Formation, eastern Alps)

The Permian Haselgebirge Formation of the eastern Alps is among the most highly deformed evaporites worldwide. In underground salt mines, it is composed of a melange of halite, anhydrite, and mudstone, with a subordinate amount of magmatic rocks. The only potassium mineral is polyhalite [K2Ca2Mg(SO4)(4)center dot 2H(2)O]. Its extreme tectonic deformation provides a challenge for reconstructing the tectono-sedimentary environment. In this context, we were able to compile a set of characteristic sedimentary and early diagenetic features of the non-halite components. In particular, mudstone and anhydrite pseudomorphs after gypsum preserve synsedimentary structures. While mudstone represents the overall background sedimentation, sulfate precipitated mainly at the brine surface under pelagic conditions. The large amount of mudstone (50%) was probably trapped as mud in a quiet lagoonal basin. Its magnesium-dominated mineral composition is in accordance with coeval halite precipitation from seawater. Earthquake-induced deformation structures formed in the semiductile mud sediment as mostly ramified, centimeter-scale sedimentary dikes, which originated intrastratally by liquefaction. Permian volcanism is documented by a basaltic body from the Hallstatt salt mine, which exhibits a sedimentary contact with the mudstone. Its immobile trace-element composition favors an intraplate origin consistent with a rift stage. During subsequent burial, authigenic minerals such as quartz and feldspar started to grow. The origin of polyhalite relates to the mobilization of complex fluids and roughly coincides with the final, late Middle Triassic opening of the Meliata Ocean. All evidence from syn-sedimentary deformation and early diagenesis confirms the deposition of the evaporites in a late thinning stage of an ancient rift.

Synthesis of Layered Rare-Earth Hydroxide Intercalated with Benzoate Ions

We report a new family of lanthanide-based inorganic-organic hybrid frameworks Y1.9Eu0.1(OH)(5)[C6H5COO] center dot 2H(2)O synthesized by homogeneous precipitation. The crystal structure obtained from powder X-ray diffraction data revealed that this material comprises two-dimensional cationic lanthanide hydroxide {[Ln(2)(OH)(5)(H2O)](+)}(infinity) layers, which are cross-linked by benzoate ligands into a three-dimensional pillared framework. The single layered nanosheets were obtained in n-butanol after the supersonic treatment. The morphologies of the nanosheets were a hexagonal structure about 800 nm in size as determined by transmission electron microscopy, and the thickness of the nanosheets was about 1.8 nm measured by atomic force microscopy. The fluorescence intensity of the D-5(0)-F-7(2) transition increased nearly 3.8 times. The lifetime of the material increased to 0.43 ms compared with the lifetime of Eu3+ in an aqueous medium of 0.1 ms.

Investigation on the Sodium and Potassium Tetrasalts of 1,1,2,2‐Tetranitraminoethane

With respect to high-energy dense materials with high oxygen-content, the tetrasodium salt of 1,1,2,2-tetranitraminoethane as monohydrate Na(4)TNAE center dot H2O (4) and the tetrapotassium salt as dihydrate K(4)TNAE center dot 2H(2)O (5) were synthesized and reported for the first time together with their crystal structures at 173 K. Whilst 4 cannot be dehydrated the crystal water content of 5 can be removed irreversibly at 160 degrees C to obtain K(4)TNAE (6) as demonstrated by DTA and TGA measurements. K(4)TNAE (6) was demonstrated using the small scale reactivity test to be a inferior explosive to RDX and CL-20. However the anionic nitramine compound was measured to be less toxic against Vibrio fischeri than RDX (EC50: 240 mg.L-1) with respect to its EC50 value above 15070 mg.L-1. This demonstrates that the introduction of anionic nitramine moieties is a promising concept for the stabilization of energetic materials with lower toxicity.

The Inhibition Effect of Polyaspartic Acid and Its Mixed Inhibitor on Mild Steel Corrosion in Seawater Wet/Dry Cyclic Conditions

The inhibition effects of polyaspartic acid (PASP) and the mixed inhibitor (50mg/L PASP, 100mg/L Na2WO4, 100mg/L ZnSO4 center dot 7H(2)O) on mild steel corrosion in seawater wet/dry cyclic conditions were studied via weight loss and electrochemical methods. The polarization curves show that the inhibition efficiency is 72.4% in the presence of PASP, and rises up to 92.6% after the addition of the mixted inhibitor. Scanning electron microscopy (SEM), X-ray diffraction and Fourier transform infrared reflection were performed to study the corrosion inhibition effect. According to the results of SEM, the metal surface immersed in the mixed inhibitor was better protected than that in PASP due to the formation of a protective film.

Synthesis, spectroscopic studies and crystal structure of (Et4N)(SnMe3)(7)(HASO(4))(4) center dot 2H(2)O

On allowing tetraethylammonium dihydrogen arsenate dihydrate to react with trimethyltin chloride, the title compound has been obtained and characterized by infrared, Mossbauer and NMR techniques. Its crystal structure has been determined and consists of layers containing both corner sharing AsO4H tetrahedra and trans-O2SnC3 entities. It contains large cavities in which tetraethylamonium cations are located. (C) 2004 Elsevier B.V. All rights reserved.

Synthesis of ZnO Particles by Parallel Flow Precipitation Hydrothermal Process and their Photocatalytic Performance

ZnO particles were synthesized by a parallel flow precipitation hydrothermal process with Zn(NO3)(2)center dot 6H(2)O and NH3 center dot H2O as raw materials. The morphology and structure of as-synthesized ZnO particles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and Brunauer-Emmett-Teller (BET) surface area analysis. The results revealed that all of the obtained ZnO samples had a hexagonal wurtzite structure, with the precipitation reaction pH being a key factor in the formation of the hexagonal prism structure. The photocatalytic activity of ZnO was evaluated via Rhodamine B (RhB) dye degradation. The ZnO-3 sample synthesized at a precipitation pH = 6.8 possessed excellent photocatalytic degradation effciency after three photocatalytic experiments. No significant change of photocatalytic activity could be detected when NO3- was added, however, the presence of SO42- and Cl- reduced the photocatalytic activity, with SO42- most severely reducing activity.

Explosive Properties of 4,4’,5,5’-Tetranitro-2,2’-bi-1H-imidazole Dihydrate

This paper reports measured explosive properties of 4,4',5,5'-tetranitro-2,2'-bi-1H-imidazole dihydrate (TNBI center dot 2H(2)O). Non-isothermal kinetics analysis, calorimetric measurements, detonability tests, small-scale shock reactivity tests (SSRT), detonation velocity measurements and cylinder tests were performed. The results of the cylinder tests were used to determine the acceleration ability of TNBI center dot 2H(2)O. Some experiments were conducted also with TNT, NTO, FOX-7 and RDX. Our experimental studies have shown that TNBI center dot 2H(2)O is a thermodynamically stable compound, surpassing TNT with regard to its energetic and detonation parameters. The results of the SSRT indicate that this material has better performance in small charges than RDX, FOX-7 and NTO.

In-situ Synthesis and Discharge Performance of Ni-NiCl$lt;inf$gt;2$lt;/inf$gt; Composite as Cathode Materials for Thermal Batteries

As a high potential compound, NiCl2 is an ideal anode material for high powder thermal battery, but its small specific surface area and poor conductivity hinder the application in thermal battery. In present study, The Ni-NiCl2 composite with high specific surface area and conductivity was prepared by sublimation and in-situ synthesis, as cathode materials for thermal batteries. The precursor material NiCl2 center dot 6H(2)O was dried to dehydrate and sublimated at 850 similar to 900 degrees C in Ar atmosphere successively. And then the yellow sublimed powder was reduced at 300 similar to 500 degrees C in Ar + H-2 atmosphere for 1 h. Finally, the Ni and NiCl2 composite powders were formed. Thermoanalysis, crystal structure, in-situ synthesis process and electrochemical performance of the powders were analyzed. The results show that NiCl2 crystal grows along the direction perpendicular to c axis and formed a layered structure of 200-300 mu m in the sublimation process. The resistivity of Ni-NiCl2 composite is reduced with the increase of elemental Ni content. The discharge curve of LiSi vertical bar LiCl-LiBr-LiF vertical bar NiCl2 thermal batteries with Ni-NiCl2 (5wt% elemental Ni) as anode material at 1000 mA/cm(2) is more stable and has a shorter activation time, as compared to the discharge curve with pure NiCl2 as anode material.

Crystal structure of hydrated fluoridesMF2·4H2O (M= Zn, Ni, Co): a combined approach

Crystal structure of hydrated fluorides MF2 center dot 4H(2)O (M=Zn, Ni, Co) : a combined approach

Hysteretic Gas and Vapor Sorption in Flexible Interpenetrated Lanthanide-Based Metal–Organic Frameworks with Coordinated Molecular Gating via Reversible Single-Crystal-to-Single-Crystal Transformation for Enhanced Selectivity

A series of flexible 3-fold interpenetrated lanthanide-based metal organic frameworks (MOFs) with the formula [Ln(HL)(DMA)(2)]center dot DMA center dot 2H(2)O, where Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Er, DMA = dimethylacetamide, and H4L = 5,5'-(2,3,5,6-tetramethyl-1,4-phenylene)bis(methylene)bis(azanediyl)diisophthalic acid, have been prepared. [Sm(HL)(DMA)(2)]center dot DMA center dot 2H(2)O was studied as an exemplar of the series. The activated Sm(HL)(DMA)(2) framework exhibited reversible single-crystal-to-single-crystal (SCSC) structural transformations in response to adsorption and desorption of guest molecules. X-ray single crystal structural analysis showed that activation of [Sm(HL)(DMA)(2)]center dot DMA center dot 2H(2)O by heat treatment to form Sm(HL)(DMA)(2) involves closing of 13.8 x 14.8 angstrom channels with coordinated DMA molecules rotating into the interior of the channels with a change from trans to cis Sm coordination and unit cell volume shrinkage of similar to 20%, to a void volume of 3.5%. Solvent exchange studies with CH2Cl2 gave [Sm(HL)(DMA)2]center dot 2.8CH(2)Cl(2) which, at 173 K, had a structure similar to that of trans-[Sm(HL)(DMA)2]center dot DMA center dot 2H(2)O. CH2Cl2 vapor sorption on activated cis-[Sm(HL)(DMA)(2)] results in gate opening, and the fully loaded structure has a similar pore volume to that of trans-[Sm(HL)(DMA)2]center dot 2.8CH(2)Cl(2) structure at 173 K. Solvent exchange and heat treatment studies also provided evidence for intermediate framework structural phases. Structural, thermodynamic, and kinetic aspects of the molecular gating mechanism were studied. The dynamic and structural response of the endothermic gate opening process is driven by the enthalpy of adsorption, entropic effects, and Fickian diffusion along the pores produced during framework structure development thus relating the structure and function of the material. Exceptionally high CO2 selectivity was observed at elevated pressure compared with CH4, H2, O-2, and N-2 due to molecular gate opening of cis-[Sm(HL)(DMA)(2)] for CO2 but not for the other gases. The CO2 adsorption induced the structural transformation of cis-[Sm(HL)(DMA)(2)] to trans-[Sm(HL)(DMA)(2)], and hysteretic desorption behavior allows capture at high pressure, with storage at lower pressure.

Synthesis, characterization and formation mechanism of friedel’s salt (FS: 3CaO·Al2O3·CaCl2·10H2O) by the reaction of calcium chloride with sodium aluminate

The synthesis of Friedel's salt (FS: 3CaO center dot Al2O3 center dot CaCl2 center dot 10H(2)O) by the reaction of calcium chloride with sodium aluminate was investigated. Factors affecting the preparation of Friedel's salt, such as reaction temperature, initial concentration, titration speed, aging time and molar Ca/Al ratio were studied in detail. XRD, SEM images and particle size distribution show that the reaction temperature, aging time and molar Ca/Al ratio have significant effect on the composition, crystal morphology, and average particle size of the obtained samples. In addition, the initial CaCl2 concentration and NaAlO2 titration speed do not significantly influence the morphology and particle sue distribution of Friedel's salt. With the optimization of the operating conditions, the crystals can grow up to a average size of about 28 mu m, showing flat hexagonal (or pseudohexagonal) crystal morphology. Moreover, two potential mechanisms of Friedel's salt formation including adsorption mechanism and anion-exchange mechanism were discussed. In the 'adsorption mechanism, Frieders salt fonus due to the adsorption of the bulk Cl- ions present in the solution into the interlayers of the principal layers, [Ca2Al(OH-)(6)center dot 2H(2)O](+), in order to balance the charge. In the anion-exchange mechanism, the freechloride ions bind with the AFm (a family of hydrated compounds found in cement) hydrates to form Friedel's salt by anion-exchange with the ions present in the interlayers of the principal layer, [Ca2Al(OH-)(6)center dot 2H(2)O](+)-OH-.

Ježekite, Na8[(UO2)(CO3)3](SO4)2·3H2O, a new uranyl mineral from Jáchymov, Czech Republic

Jezekite (IMA2014-079), Na-8[(UO2)(CO3)(3)](SO4)(2)center dot 3H(2)O, is a new uranyl carbonate-sulfate mineral from Jachymov, Western Bohemia, Czech Republic. The new mineral was found on samples from the Geschieber vein in the Svornost mine. It occurs as a crystalline crust composed of thin, bladed prismatic crystals of yellow to sulfuric yellow color on a gangue along with andersonite, cejkaite, schrockingerite and ubiquitous gypsum. It is a supergene, low-temperature mineral formed by hydration-oxidation weathering of uraninite associated with post-mining processes. Jezekite is hexagonal, space group P-62m, with unit-cell parameters a = 9.0664(11), c = 6.9110(6)angstrom and V = 491.97(12)angstrom(3), Z = 1. Crystals are thin blades elongated along [001]. Crystals exhibit the forms {001}, {1-11}, {100} and {010}, commonly forming twins/intergrowths with a twin plane parallel to [001]. Jezekite is light yellow to sulfuric yellow and has a very pale yellow streak. It exhibits a bright greenish white fluorescence under both long-wave and short-wave UV. It is transparent with a vitreous to pearly luster. The mineral has a Mohs hardness similar to 2; it is brittle, with uneven fracture and a perfect cleavage on {001} and along [010]. The calculated density based on the empirical formula is 2.966 g/cm(3). The mineral is optically uniaxial (+), with omega = 1.484(2) and epsilon = 1.547(2) (589 nm). It is non-pleochroic. The chemical composition of jezekite (wt. %, electron-microprobe) is: Na2O 27.92, SO3 18.49, UO3 32.85, CO2 (calc.) 15.08, H2O (calc.) 6.17, total 100.51, which yields the empirical formula Na-7.88 (UO2)(CO3)(3)(S1.01O4)(2)center dot 3H(2)O (based on 22 O apfu). Prominent features in the Raman spectrum include the O-H stretching vibrations, symmetric stretching vibrations of (UO2)(2+) ions, and stretching and bending vibrations of symmetrically non-equivalent CO3 groups and highly disordered SO4 tetrahedra. The eight strongest powder X-ray diffraction lines for jezekite are [d(obs)angstrom(I-rel.) (hkl)]: 7.861(59)(100), 6.925(20)(001), 5.193(100)(101), 4.534(44)(110), 3.415(23)(201), 2.751(17)(112), 2.728(20)(211), 2.618(25)(300). The crystal structure of jezekite (R = 0.043 for 444 reflections with I-obs > 3 sigma[I]) contains finite uranyl tricarbonate clusters linked through the Na-O bonds to form sheets of the composition {Na-2[(UO2)(CO3)(3)]}(2-) parallel to (001). The adjacent sheets of polyhedra are also linked through Na-O bonds to the six Na2 atoms and highly disordered sheets of composition {[(SO4)(2)(H2O)(3)]}(4-) into a sandwich-like structure. The new mineral is named after Professor Bohuslav Jezek (1877-1950), a prominent Czech mineralogist and crystallographer

A new and facile CuCl2 center dot 2H(2)O-catalyzed one-pot three-component synthesis for quinazolines

A new and facile CuCl2 center dot 2H(2)O-catalyzed one-pot three-component synthesis for quinazolines

The influence of sodium and barium ions on the structures of iridium (III) acetylacetonate complexes

Two iridium acetylacetonate complexes [Na(H2O)Ir(acac)(2)Cl-2] (n) (compound 1) and [Ba(H2O)(5)Ir(acac)(2)Cl2Ba(H2O)(5)][Ir(acac)(2)Cl-2](3)center dot 2H(2)O (compound 2) were synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, NMR, IR, and absorption spectra. The influence of sodium and barium ions on their molecular structures was explored.

Tin-Incorporation Induced Changes in the Microstructural, Optical, and Electrical Behavior of Tungsten Oxide Nanocrystalline Thin Films Grown Via Spray Pyrolysis

Undoped and Sn-doped WO3 thin films were grown on cleaned glass substrates by chemical spray pyrolysis, using ammonium tungstate (NH4)(2)WO4 as the host precursor and tin chloride (SnCl4 center dot 5H(2)O) as the source of dopant. The XRD spectra confirm the monoclinic structure with a sharp narrow peak along (200) direction along with other peaks of low relative intensities for all the samples. On Sn doping, the films exhibit reduced crystallinity relative to the undoped film. The standard deviation for relative peak intensity with dopant concentration shows enhancement in heterogeneous nucleation growth. As evident from SEM images, on Sn doping, appearance of island-like structure (i.e., cluster of primary crystallites at few places) takes place. The transmittance has been found to decrease in all the Sn-doped films. The optical band gap has been calculated for both direct and indirect transitions. On Sn doping, the direct band gap shows a red shift and becomes 2.89 eV at 2 at.% doping. Two distinct peaks, one blue emission at 408 nm and other green emission at 533 nm, have been found in the PL spectra. Electrical conductivity has been found to increase with Sn doping.

Effect of Reduction Treatment on Structural Properties of TiO2 Supported Pt Nanoparticles and Their Catalytic Activity for Benzene Oxidation

A series of highly active Pt-TiO2 catalysts have been prepared by impregnation methods via different reduction processes and used for catalytic decomposition of benzene. The oxidized and reduced Pt-TiO2 catalysts exhibit apparent differences in physical/chemical features (e.g. particle size, chemical state, and electronic property of Pt nanoparticles, and surface oxygen) and catalytic activities for benzene oxidation. Nearly 100 % benzene conversion is achieved on Pt-TiO2 catalysts obtained by the sodium citrate (C6H5Na3O7 center dot 2H(2)O, Na(3)Ct) reduction at approximate 160 A degrees C. Metallic Pt nanoparticles have strong capacity for oxygen activation, and the negative charges and rich chemisorbed oxygen on the surface of metallic Pt nanoparticles are probably responsible for their high catalytic activities for benzene oxidation. 1 wt% Pt-TiO2 catalysts have been prepared by impregnation methods via different reduction processes and used for catalytic decomposition of benzene. The oxidized and reduced catalysts exhibit apparent differences in physical/chemical features and catalytic activities for benzene oxidation. Metallic Pt nanoparticles have strong capacity for oxygen activation, and the negative charges and rich chemisorbed oxygen on the surface of metallic Pt nanoparticles are probably responsible for their high catalytic activities for benzene oxidation.

Synthesis, Crystal Structure and Magnetic Properties of a Nd(III) Coordination Polymer Constructed by 3-Carboxyphenoxyacetate and 1,10-Phenanthroline

Under hydrothermal conditions, NdCl3 center dot 6H(2)O reacts with 3-H(2)CPOA (3-H(2)CPOA=3-carboxyphenoxyacetatic acid) and phen (phen=1,10-phenanthroline), producing a novel coordination polymer [Nd(3-CPOA)(1.5)(phen)](n) (1). Complex 1 crystallizes in monoclinic space group P2(1)/c, with a=0.982 7(8), b=1.140 6(10), c=2.115 8(19) nm, beta=90.574(9)degrees, V=2.371(4) nm(3), and Z=4. X-ray diffraction studies show that complex 1 possesses a three-dimensional framework structure based on a binuclear unit. Magnetic studies for complex 1 indicate the presence of stronger antiferromagnetic coupling between the adjacent NO ions. CCDC: 888765.

Environmental remediation of Direct Blue dye solutions by photocatalytic oxidation with cuprous oxide

A simple hydrothermal route has been developed to synthesize shape-controllable Cu2O from starting materials of CuCl2 center dot 2H(2)O and NaOH by changing the hydrothermal temperature from 80 to 140 degrees C. Cu2O nanorods, a mixture of nanorods and nanocubes or nanocubes have been synthesized by controlling the hydrothermal temperature. The experiments demonstrate that the hydrothermal temperature is an important parameter that may determine whether the Cu2O is shaped as nanorods, a mixture of nanorods and nanocubes or nanocubes. The products were characterized with X-ray diffraction (XRD), ultraviolet and visible spectroscopy (UV-vis), transmission electron microscopy (TEM) and surface area measurements. Furthermore, the photocatalytic performance of Cu2O was measured in the degradation of Direct Blue dye with visible light.

Synthesis of ZnSe Nanomaterials via Solvothermal Method

Sphalerite or wurtzite ZnSe nanomaterials were controllably synthesized by one-step solvothermal technique using ethanol amine (EA) as solvent, zinc acetate as zinc source and Na2SeO3 center dot 5H(2)O or Se powder as Se source. X-ray diffraction (XRD), energy dispersive spectrum (EDS), scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to characterize the structures, compositions and morphologies of the products. The results show that sphalerite ZnSe nanoparticles with the diameter of 30 nm are synthesized by adopting Na2SeO3 center dot 5H(2)O as Se source, while wurtzite ZnSe nanoplates with thickness of 50 nm are prepared via Se powders as Se source. The above results indicate that the structures and morphologies of the ZnSe nanomaterials are dependent on the Se sources. It is also found that EA solvent and Se source play an important role in the formation of ZnSe nanomaterials. The optical properties of the as-prepared products are characterized by UV-Vis absorption and room-temperature photoluminescence (PL) spectra.