Thermal stability of Ba1-xCaxF2 solid solutions

Ba_1-xCa_xF₂ samples with fluorite-type structure were prepared by high-energy ball milling. DSC measurements revealed exothermic decomposition at temperatures of about 450 °C. Decomposition was also observed by high temperature X-ray experiments. As a product, two phases with compositions close to pure BaF₂ and CaF₂ were obtained. The decomposition temperature observed by X-ray measurements is lower than in the DSC experiments. This might indicate that X-ray irradiation could foster the decomposition.     

Synthesis and structure of phosphates M<Subscript>0.5</Subscript>Ti<Subscript>2</Subscript>(PO<Subscript>4</Subscript>)<Subscript>3</Subscript>

Phosphates M_0.5Ti₂(PO₄)₃ (M = Ni, Zn) were synthesized by the sol-gel method and characterized by the methods of X-ray diffraction, IR spectroscopy, and electronic microprobe analysis. Structures of Ni_0.5Ti₂(PO₄)₃ and Zn_0.5Ti₂(PO₄)₃ were studied by Rietveld method using the X-ray powder diffraction data.     

Solid Solutions of the System V<Subscript>2</Subscript>O<Subscript>5</Subscript>-V<Subscript>2</Subscript>O<Subscript>4</Subscript>-TiO<Subscript>2</Subscript> in Air

Gravimetry in combination with X-ray phase analysis, X-ray crystallography, and X-ray densitometry were used to determine the contents of V⁵⁺, V⁴⁺, and Ti⁴⁺ ions and vacancies in solid solutions formed by the reaction of V₂O₅ with TiO₂ in air at atmospheric pressure.     

Solid-phase synthesis of nanocrystalline lanthanum zirconate using mechanical activation

Nanocrystalline lanthanum zirconate La₂Zr₂O₇ was synthesized by the solid-phase method using preliminary mechanical activation of a La₂O₃ and ZrO₂ mixture. Processes occurring during heating the mixture of mechanoactivated lanthanum and zirconium oxides were studied using the X-ray phase analysis, IR spectroscopy, and complex thermal analysis. Synthesized lanthanum zirconate was characterized by the X-ray phase analysis and transmission electron microscopy methods.     

Analytical characterization of BCxNy films generated by LPCVD with triethylamine borane

Triethylamine borane (TEAB) and He, N₂ or NH₃ were applied as additional reaction gases in the production of BC_xN_y layers by low-pressure chemical vapor deposition (LPCVD). These layers were deposited on Si(100) wafers and characterized chemically by X-ray photoelectron spectroscopy (XPS) and synchrotron radiation-based total-reflection X-ray fluorescence analysis combined with near-edge X-ray absorption fine-structure spectroscopy (TXRF-NEXAFS). The composition of the material produced without NH₃ was found to be dominated by B–C bonds with the stoichiometric formula B₂C₃N. B–N bonds with the formula B₂CN₃ were preferred when NH₃ was added. A first attempt was made to compare the results obtained by applying trimethylamine borane and TEAB as single-source precursors.     

草酸铕颗粒微米层状颗粒的合成及其光学性能

Hierarchical europium oxalate Eu₂(C₂O₄)₃·10H₂O micro-particles were synthesized through a simple precipitation method at room temperature in present of trisodium citrate. The prod-ucts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, and photoluminescence. The possible formation mechanism of the hierarchical europium oxalate Eu₂(C₂O₄)₃·10H₂O micro-particles was discussed.     

SnO2 纳米棒的氧化还原特性

 利用室温固相反应在 NaCl-KCl 熔盐介质中, 通过焙烧含 SnO2 纳米颗粒前驱体合成了 SnO2 纳米棒, 并采用 X 射线衍射、扫描电镜、透射电镜、选区电子衍射和 X 射线光电子能谱对 SnO2 纳米棒进行了表征. 结果表明, SnO2 纳米棒是表面光滑、结晶完整的金红石结构单晶体, 直径为 10~20 nm, 长度为几百纳米到几个微米. 程序升温还原结果表明, SnO2 纳米棒具有较好的氧化还原性能和催化活性. 探讨了 SnO2 纳米棒的氧化还原机理.     

Preparation of Powders and Films of NiAl2O4 Spinel from a Structurally Characterized Molecular Precursor, NiAl2(acac)4(O i Pr)4

Interaction of Ni(acac)₂ with 2 eq. of Al(O ⁱ Pr)₃ in toluene on reflux with subsequent modification with 2 eq. of acetylacetone offers with quantitative yields a new heterometallic complex, NiAl₂(acac)₄(O ⁱ Pr)₄ (1), characterized by X-ray single crystal study and variety of spectroscopic techniques. Uniform NiAl₂O₄-coatings were obtained on Al₂O₃ substrates by dip-coating from toluene solutions of 1 with subsequent thermal treatment and characterized by X-ray powder, SEM and AFM studies. Powder samples were obtained by hydrolysis of solutions of 1 in the moist air and characterized by TG and X-ray powder data.     

CoFe2O4@SiO2-PA-CC-guanidine nanoparticles: A novel,efficient, and recyclable catalyst for the synthesis of 3,5-disubstituted-2,6-dicyanoaniline derivatives

A new and efficient procedure for the synthesis of 3,5-disubstituted-2,6-dicyanoaniline derivatives by CoFe₂O₄@SiO₂-PA-CC-guanidine magnetic nanoparticles (MNPs) was reported. 3,5-Disubstituted-2,6-dicyanoaniline derivatives were synthesized from malononitrile, aldehydes, and β-nitrostyrene derivatives in good yields. MNPs used for the synthesis of aniline derivatives were easy to recover and reuse. The CoFe₂O₄@SiO₂-PA-CC-guanidine MNPs were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetric analysis, and vibration sample magnetometry techniques.     

Struktur und Eigenschaften von ternären und quaternären Seltenerd — Übergangsmetall-Oxidsystemen vom K2NiF4-und CaFe2O4-Typ

New compounds from K₂NiF₄- and CaFe₂O₄-type were prepared by solid state reactions. From X-ray, magnetic and X-ray spectroscopic investigations the scatter of intensities, ratio of valences and the magnetic behaviour of the individually compounds are discussed.     

Single-crystalline α-Fe2O3 with hierarchical structures: Controllable synthesis, formation mechanism and photocatalytic properties

A dual iron precursors system in a hydrothermal process was developed for controllable fabrication of α-Fe₂O₃ hierarchical structures with different morphologies. Micro-pines, snowflakes and bundles were successfully synthesized simply by tuning the total concentration of the two iron precursors K₄[Fe(CN)₆] and K₃[Fe(CN)₆] and their molar ratio. The obtained α-Fe₂O₃ hierarchical structures were characterized using field-emission scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy and energy-dispersive X-ray analysis. The effect of experimental conditions on the morphologies of the α-Fe₂O₃ crystals was systematically investigated. A possible formation mechanism of different α-Fe₂O₃ hierarchical structures was proposed. Good photocatalytic properties were observed for all the hierarchical structures.     

常温常压下硼磷酸盐的直接合成与形成过程研究

在常温常压条件下直接合成了硼磷酸盐NaCd(H₂O)₂[BP₂O₈]·0.8H₂O(Hexagonal，P6₁22，a=0.971 30(14) nm，c=1.613 6(3) nm，V=1.318 36(40) nm³，Z=6)和NaZn(H₂O)_2<     

基于2,5-二溴对苯二羧酸配体的镧系金属有机骨架的合成、结构及性质

采用溶剂热法, 以2, 5-二溴对苯二甲酸(H₂L)为配体, 分别与六水合硝酸钕、六水合硝酸钆反应合成了 2种镧系金属有机骨架(MOFs):{[Nd₂(L)₃(DMF)₂(H₂O)₂]·2DMF}_n (1)和{[Gd₂(L)₃(DMF)₂(H₂O)₂]·2DMF}_n (2)。通过单晶X射线衍射、粉末X射线衍射、红外光谱、元素分析、荧光光谱、热重分析等测试方法对其进行了结构表征与性质研究。结果表明, 2个配合物均是以稀土离子为金属节点, 与配体相互连接, 形成无限延伸的三维网状结构。     

A new strategy for fabrication Fe2O3/SiO2 composite coatings on the Ti substrate

We report here on the synthesis of homogenous, well-adherent composite film of Fe₂O₃/SiO₂, up to 7 μm thick, on the titanium substrate by anodic treatment optimized for an aqueous suspension of K₂O·SiO₂ and Fe₂O₃ powder under galvanostatic conditions. The end products were characterized by scanning electron microscopy, energy-dispersive X-ray, X-ray powder diffractometry, X-ray photoelectron spectroscopy, and Mössbauer spectroscopy, concluding that the formation of composite coating at the SiO₂ to Fe₂O₃ ratio of approximately 1:1 proceeds just after formation of a thin TiO₂ layer with Fe₂O₃ particle inclusions without transformations via an electrophoresis deposition of negatively charged Fe₂O₃ species enveloped by silica ions.     

Bipolar Electrochemistry Exfoliation of Layered Metal Chalcogenides Sb2S3 and Bi2S3 and their Hydrogen Evolution Applications

Efficient exfoliation and downsizing of Sb₂S₃ and Bi₂S₃ layered compounds by using scalable bipolar electrochemistry on their suspensions in aqueous media are here demonstrated. The resulting samples were characterized in detail by transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy; their electrochemistry toward hydrogen evolution was also investigated. Hydrogen evolution ability of exfoliated Sb₂S₃ and Bi₂S₃ was investigated and compared to the bulk counterparts.     

Low-Pressure Chemical Vapor Deposition of Silicon Carbide Thin Films from Organopolysilanes

(Me₃Si)₂SiMe₂, (Me₃Si)₃SiMe and (Me₃Si)₄Si were used as precursors for the deposition of polycrystalline β-SiC thin films on silicon substrates at 1000–1200°C in a low-pressure hot-wall chemical vapor deposition reactor. The thin films were analyzed by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy.     

The Effect of SiO2 Addition on the Grain Size and Photocatalytic Activity of TiO2 Thin Films

The uniform transparent TiO₂/SiO₂ nanometer composite thin films were prepared via sol-gel method on the soda lime glass substrates, and were characterized by X-ray photoelectron spectroscopy (XPS), FTIR spectroscopy, UV-VIS spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and BET surface areas. It was found that the addition of SiO₂ to TiO₂ thin films could suppress the grain growth of TiO₂ crystal and increase the hydroxyl content of the surface of TiO₂ films. The photocatalytic activity of the as-prepared TiO₂/SiO₂ composite thin films increases for SiO₂ content of less than 5 mol%.     

Synthesis and study of uranyl arsenate (UO<Subscript>2</Subscript>)<Subscript>3</Subscript>(AsO<Subscript>4</Subscript>)<Subscript>2</Subscript> · 12H<Subscript>2</Subscript>O

A method for producing synthetic troegerite of composition(UO₂)₃(AsO₄)₂ · 12H₂. Owas developed. X-ray diffraction, IR spectrometry, X-ray fluorescence analysis, and scanning calorimetry were used to study its dehydration and thermal decomposition, to solve the structgure, and to determine X-ray diffraction and IR spectroscopic characteristics.     

An X-ray photoelectron spectroscopic study of novel SiON glasses

Novel SiON glasses obtained by melting mixtures of crystalline α-SiO₂ and α-Si₃N₄ were investigated by means of X-ray photoelectron spectroscopy (XPS). The incorporation of nitrogen into the SiO₂ network was recently proved by ²⁹Si-MAS-NMR (magic-angle spinning nuclear magnetic resonance) and Si K-XANES (X-ray absorption near edge structure). The Si 2p XPS and the Si KLL XAES (X-ray excited Auger electron spectroscopy) studies of the SiON glasses confirm the formation of mixed structural units (SiO_xN_4-x) by the presence of an additional spectral component energetically located between SiO₂- and Si₃N₄-like signals. The N 1s and O 1s XPS spectra support the conclusion about the incorporation of nitrogen into the SiO₂ network.     

Silver-coated TiO2 nanostructured anode materials for lithium ion batteries

Anatase TiO₂ nanoribbons/nanotubes (TiO₂-NRTs) have been synthesised successfully via a reflux method followed by drying in a vacuum oven, and then, silver-coated TiO₂ NRTs (Ag/TiO₂-NRTs) were prepared by coating silver particles onto the TiO₂-NRTs surface by the traditional silver mirror reaction. The physical properties of the synthesised products were examined in detail using X-ray diffraction, field emission gun scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy, respectively. The results indicated that the Ag nanoparticles were uniformly deposited on the surface of the TiO₂ nanoribbons/nanotubes. The electrochemical properties were investigated by a variety of techniques. The rate capability and cycle durability for the Ag/TiO₂-NRTs were improved compared with TiO₂-NRTs. It is speculated that the Ag-coated TiO₂ nanoribbons/nanotubes are an effective anode candidate for lithium ion batteries.