Synthesis and Characterization of Layered Perovskite-type Organic-inorganic Hybrids(C_nH_(2n+1)NH_3)_2(CH_3NH_3)_(m-1)Pb_mI_(3m+1)(n=5-10,m=1,2)

Layered organic-inorganic hybrids(C_nH_(2n+1)NH_3)_2(CH_3NH_3)_(m-1)Pb_mI_(3m+1) containing monolayer(m=1) and bilayer(m=2) perovsikte were synthesized by reactions in solution.The influences of the reactant ratio,solvent,reaction temperature,and reaction time on the structures of the products were investigated.The structures and the properties of the hybrids were characterized using X-ray diffraction(XRD),scanning electron microscopy(SEM),and ultraviolet and visible(UV) absorption spectroscopy.The XRD patterns and the SEM images demonstrate that the pure bilayer perovskite hybrids are obtained.The UV-vis spectra indicate that the number of the inorganic perovskite layer(m) has greater impact on the band gap than the number of the carbon atoms(n).The band gap of bilayer hybrids(around 1.9 eV) is significantly less than that of monolayer hybrids(around 2.2 eV).     

Low pressure synthesis of boron nitride with (C2H5)2O · BF3 and Li3N precursor

Cubic boron nitride(c-BN) was synthesized through benzene thermal method at a lower temperature of 300 °C by selecting liquid (C₂H₅)₂O · BF₃ and Li₃N as reactants. Hexagonal boron nitride(h-BN) and orthorhombic boron nitride(o-BN) were also obtained. The samples were characterized by X-ray powder diffractometry and Fourier transformation infrared spectroscopy. The results show that all the BF₃, BCl₃ and BBr₃ in the same family compounds can react with Li₃N to synthesize BN since the strongest bond of B-F can be broken. Compared with BBr₃, liquid (C₂H₅)₂O · BF₃ is cheaper, less toxic and more convenient to operate. Li₃N not only provides nitrogen source but also has catalytic effect on accelerating the formation of c-BN at low temperature and pressure. Foundation item: Projects(20273007,50372006) supported by the National Natural Science Foundation of China     

Metal Fe, Ni and Fe-Ni Fine Fibers Derived from the Organic Gel-Thermal Reduction Process

The organic gel-thermal reduction process was successfully used for the preparation of magnetic metal Ni, Fe, Fe-Ni fine fibers from raw materials of citric acid or lactic acid and metal salts. Ni, Fe and Fe-Ni fine fibers synthesized were featured with diameters of around 1 μm and lengths of as long as 2 m for Ni fibers, 0.5 m for iron fibers, 1 m for Fe-Ni fibers. The structure, thermal decomposition process and morphologies of the gel precursors and fibers derived from thermal reduction of these gel precursors were characterized by FTIR, XRD,TG/DSC and SEM, respectively. The gel spinnability largely depends on molecular structures of metal-carboxylate complexes formed in the gel. It is reasoned that these gels consist of linear-type structural molecules [（C6H6O7）Ni]n or [（C6H5O7）2Ni3] for the nickel citrate gel, [（C3H5O3）3Fe] for the ferric lactate gel, [（C6H5O7）5（NiFe）3] for the iron-nickel citrate gel respectively and the gels obtain showed a good spinning performance.     

Heat treatment temperature effect on the microstructure and optical properties of Dy2(WO4)3 powders

Dy₂(WO₄)₃ powders were synthesized through liquid-phase reaction. The structure transformation of Dy₂(WO₄)₃ powders were analyzed by differential scanning calorimetry (DSC), X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR). The optical absorption and photoluminescence properties were characterized by UV-vis-infra diffuse reflectance spectra and fluorescence spectra. The Dy₂(WO₄)₃ host could absorb deep UV light and transfer the energy of UV light to Dy³⁺ ions, which convert the high-energy UV light to blue light (482 nm, ⁴ F _9/2→⁶ H _15/2) and yellow light (547 nm, ⁴ F _9/2→⁶ H _13/2). The Dy₂(WO₄)₃ powders could also absorb near UV light and exhibit blue and yellow emissions near 482 and 547 nm, respectively. Heat treating promoted the crystallization and regulated the micro-structure of Dy₂(WO₄)₃ hosts. The bands of W-O_d anti-symmetric stretching vibration exhibited red shift with the increasing of sintering temperature. The W-O_b-W groups tended to combine with each other to form W-O_c-W groups after heat treating. These regulation of micro-structure had influence on the luminescent color of Dy₂(WO₄)₃. The samples could emit yellow-green, white-yellow and white light under the excitation of 350 nm after being treated at 600, 800 and 1 000 °C, respectively. The prepared Dy₂(WO₄)₃ powders have potential to act as UV absorber for solar cell to improve the conversion efficiency and also exhibit potential for white light LED.     

Synthesis and characterization of a new Fe<Subscript>2</Subscript>O<Subscript>3</Subscript> pillared triple-layered perovskite KSr<Subscript>2</Subscript>Nb<Subscript>3</Subscript>O<Subscript>10</Subscript>

A n-Hexyl NH₃Sr₂Nb₃O₁₀ is obtained by the stepwise ion-exchange reaction, then is dispersed in aqueous solution of trinuclear acetato-hydroxo iron (III) nitrate, [Fe₃(OCOCH₃)₇OH·2H₂O]NO₃, and the interlayer potassium cations of the perovskite niobate are exchanged with the partially hydrolyzed trinuclear acetato complex ions. On heating, the exchanged complex ions are converted into iron oxide pillars which keep the perovskite sheets apart. The product is characterized by XRD, SEM, EDAX and surface area measurement respectively. Zhang Hui: Born in 1970 Funded by the National Natural Science Foundation of China (No. 50002007), Major Program of Ministry of Education (No. 0201) and Open Foundation of State Key Lab of Advanced Tech. for Materials Synthesis and Processing.     

Synthesis and Characterization of a New Triple-layered Perovskite KSr2Nb3O10 and Its Protonated Compounds

New layered perovskites, KSr₂Nb₃O₁₀ and two new protonated niobates HSr₂Nb₃O₁₀·1.2H₂O and HSr₂Nb₃O₁₀, were synthesized by solid state reaction and ion-exchange reaction. These new compounds were characterized by EPMA, AAS, XRD, IR, DTA and so on. The structure may be described as treble perovskite sheets [Sr₂Nb₃O₁₀]⁻ interleaved with K⁺, H₃O⁺ or H⁺. These new compounds are new members of the Dion-Jacobsonseries with n=3 for the general formula M[A_n−1Nb_nO_3n+1], and their indexed X-ray powder diffraction data were first reported in the paper. FANG Liang: Born in 1970 Funded by Natural Science Foundation of China (No. 50002007), Major Program of Chinese Education Ministry and Open Foundation of State Key Lab. of Advanced Tech. for Materials Synthesis and Processing.     

Hydrothermal Synthesis and Characterization of Inorganic ／Organic Hybrid Complex Containing Tungstophsphate

1　IntroductionThereisasignificantinterestinpolyoxomatallatere flectingtheirdiversenovelstructure ,duetotheirapplica tionstofieldsasdiverseascatalysis ,ionexchange ,elec tricalconductivity ,magnetismandphotochemistry[1 3] .Recentlyanimportantadvanceofpoly…     

Effect of pH value on the micro-structures and optical properties of nano-crystalline CuInS<Subscript>2</Subscript> by solvothermal method

Copper indium disulfide (CuInS₂) nano-particles were synthesized by solvothermal method at 150 °C using copper (I) chloride, indium (III) chloride, thiourea and ethanol as raw materials, and characterized by X-ray diffraction(XRD), field-emission scanning electron microscope (FESEM), and UV-Vis spectra. The effects of pH value on its micro-structures and optical properties were investigated. The results show that, with the pH value increasing, the particle size of the nano-crystalline CuInS₂ increases, and its band gap becomes narrower under alkaline condition. The band gaps of CuInS₂ nano-particles are from 1.52 eV to 1.93 eV, which makes them promising candidates as absorber materials for photovoltaic applications.     

Synthesis and Characterization of Novel Chromium Catalyst and Polyethylene with High Molecular Weight

1Introduction Chromiumcatalystsplayaveryimportantroleinthe developmentofcoordinationpolymerizationofalkenes.ThechromiumbasedheterogeneousPhillipscatalystob tainedbyimpregnationofCroxidesonsilicaandthe UnionCarbideUnipolcatalystsystemderivedfromCp2Cr absorbedonsilica,arebothusedinthelarge scaleindus trialproductionofpolyolefines.Theslurry polymerization processiscurrentlyproducingaboutone thirdofthetotal amountofHDPEintheworldwiththesecatalysts[1].Dif ferentfromtheworldfamousZiegler Natta…     

Preparation and characterization of hydroxyapatite/γ-Fe2O3 hybrid nanostructure

The hybrid particles composed of hydroxyapatite (HAp) and ferrite (γ-Fe₂O₃) were synthesized by two-step precipitation method. The effect of reaction temperature on the morphology of the hybrids was also studied. The resultant hybrids were characterized by transmission electron microscopy (TEM) and X-ray diffraction analysis(XRD). It was found that γ-Fe₂O₃ nanoparticles dispersed within the HAp matrix and these hybrids had a feather-like or spherical morphology when synthesized at 90 °C or room temperature, respectively. The magnetic properties of the hybrid showed good superparamagnetic feature, and they could be controlled by the external magnetic field.     

Synthesis and characterization of 2-hydroxy-N-methyl-N-phenyl-acetamide

1　ＩＮＴＲＯＤＵＣＴＩＯＮ2 Ｈｙｄｒｏｘｙ Ｎ ｍｅｔｈｙｌ Ｎ ｐｈｅｎｙｌ ａｃｅｔａｍｉｄｅｉｓａｎｉｍｐｏｒｔａｎｔｉｎｔｅｒｍｅｄｉａｔｅｏｆｈｅｒｂｉｃｉｄｅｍｅｆｅｎａｃｅｔａｎｄｉｔｓｓｙｎｔｈｅｓｉｓｉｓｔｈｅｋｅｙｐｒｏｃｅｓｓｉｎｔｈｅ     

Preparation of crystalline Mg(OH)_2 nanopowder from serpentinite mineral

In this paper we describe a route to produce crystalline Mg(OH)2 nanopowders from serpentinite ore distributed in the Halilovskiy array(Russia, Orenburg region). An efficient extraction route consisting of treatment on serpentinite in 40% HNO_3 at 80 °C followed by NH_4OH titration for Mg(OH)_2 precipitation was demonstrated. In this study, crystalline Mg(OH)2 nanopowders have been synthesized by solvothermal reaction method using(Mg(NO_3)_2á6H_2O) which were obtained from serpentinite, NH4 OH as a precipitator, and hydroxyethylated nonylphenol as surface-active substance. Microstructure and phase composition of samples were investigated employing scanning electron microscopy(SEM) and transmission electron microscopy(TEM), X-ray phase analysis(XRD), and inductively coupled plasma optical emission spectroscopy(ICP-OES). XRD reveals that Mg(OH)2 nanopowder with high purity has the brucite structure. It was found that crystalline Mg(OH)_2 nanopowders exclusively consist of lamellar-like structures and the sizes of Mg(OH)_2 are 30–265 nm length or width.     

纯无机CsPbBr3@PMMA 复合薄膜用于白光LED 器件

纯无机钙钛矿材料具有颜色可调、带隙窄、制作工艺简单、成本低等优点, 受到了广泛的研究, 然而它在 水和氧环境中的不稳定性限制了其应用。利用聚合物在非极性溶剂中的溶胀-收缩原理将CsPbBr₃ 量子点原位生 长在聚甲基丙烯酸甲酯(PMMA) 薄膜中来提高钙钛矿量子点在水氧环境中的稳定性。该方法合成简便, 可以降低 CsPbBr₃量子点的形成温度, 并且可以得到稳定的钙钛矿相薄膜, 制得的复合薄膜具有优异的空气稳定性和耐水性, 并且具有可弯折性和高透过率, 可应用于柔性器件中。CsPbBr₃@PMMA 复合薄膜制成的白光LED 器件显示出良 好的白色发光性能, 色温为8 221 K。     

Self-cleaning glass coated with Fe^3＋ -TiO2 thin film

The self-cleaning glass coated with Fe^3 -TiO2 photocatalytic thin film was prepared by sol-gel process from the system Ti(OC4H9),-NH(C2H4OH)2-C2H5OH-H2O containing FeCl3. The microstructure and properties of the film were studied using differential thermal analysis-thermogravimetry(DTA-TG), X-ray diffration (XRD) and scanning electron microscope(SEM). The transmittance of the self-cleaning glass was measured by using UV-Vis spectrometer. The effects of content of Fe^3 and the thickness of Fe^3 -TiO2 thin film on the photocatalytic ac-tivity were examined. The results show that the photocatalytic thin films are mainly composed of Fe3O4 and TiO2 particles within 10-100 nm. The appropriate amount of Fe^3 is effective for improving the photocatalytic activities of TiO2. The best photocatalytic activity is obtained when the molar ratio of Fe^3 to TiO2 is 0. 005 and the glass is coated with 9 layers.     

Synthesis and characterization of Mg3(PO4)2-coated Li1.05Ni1/3Mn1/3Co1/3O2 cathode material for Li-ion battery

Mg₃(PO₄)₂-coated Li_1.05Ni_1/3Mn_1/3Co_1/3O₂ cathode materials were synthesized via co-precipitation method. The morphology, structure, electrochemical performance and thermal stability were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS), charge/discharge cycling and differential scanning calorimeter (DSC). SEM analysis shows that Mg₃(PO₄)₂-coating changes the morphologies of their particles and increases the grains size. XRD and CV results show that Mg₃(PO₄)₂-coating powder is homogeneous and has better layered structure than the bare one. Mg₃(PO₄)₂-coating improved high rate discharge capacity and cycle-life performance. The reason why the cycling performance of Mg₃(PO₄)₂-coated sample at 55 °C was better than that of room temperature was the increasing of lithium-ion diffusion rate and charge transfer rate with temperature rising. Mg₃(PO₄)₂-coating improved the cathode thermal stability, and the result was consistent with thermal abuse tests using Li-ion cells: the Mg₃(PO₄)₂ coated Li_1.05Ni_1/3Mn_1/3Co_1/3O₂ cathode did not exhibit thermal runaway with smoke and explosion, in contrast to the cells containing the bare Li_1.05Ni_1/3Mn_1/3Co_1/3O₂. Funded by the National Natural Science Foundation of China (No. 20273047)     

Hydrothermal Synthesis and Characterization of a Novel Organic Inorganic Hybrid Compound [Co（dien）2]（dienH3）（H3O）7[P2Mo5O23]2·14H2O

A new compound,[Co（dien）2]（dienH3）（H3O）7[P2Mo5O23]2·14H2O, has been hydrothermallly synthesized by using Na2MoO4,CoCl2, H3PO4 and dien, and structurally characterized by elemental analysis, X-ray powder diffraction analysis, SEM, IR and TG analysis. The results show that the compound is composed of a polyanion [P2Mo5O23]2^12, complex [Co（dien）2]^2＋ cation, protonated [dienH3]^3＋ , and forteen crystallization water molecule.     

Co-precipitation/hydrothermal synthesis of BiFeO<Subscript>3</Subscript> powder

A coprecipitation/hydrothermal route was utilized to fabricate pure phase BiFeO3 powders using FeCl3·6H2O and Bi（NO3）3·5H2O as starting materials, ammonia as precipitant and NaOH as mineralizer. The synthesized powders were characterized by XRD, SEM and DSC-TG analysis. In the process, single-phase BiFeO3 powders could be obtained at a hydrothermal reaction temperature of 180 ℃, with NaOH of 0.15 mol/L, in contrast to 200 ℃ and 4 mol/L for conventional hydrothermal route. Meanwhile, the micro-morphology of synthesized BiFeO3 powders changed with different reaction temperatures and concentrations of NaOH. The N6el temperature, Curie temperature and decomposition temperature of the synthesized BiFeO3 powders were detected to be 301 ℃, 828 ℃ and 964 ℃, respectively. The hydrothermal reactions mechanism to fabricate BiFeO3 powders were discussed based on the in-situ transformation process.     

Comparison of energy structure and spectral properties of Ce:LaAlO3 and Ce:Lu2(SiO4)O

Undoped LaAlO₃ and 1 at.% Ce:LaAlO₃ single crystals were grown by the Czochralski process. Absorption and fluorescence spectra were measured at room temperature. Detailed energy levels structure of Ce:LaAlO₃ was determined. In this paper, two viewpoints were provided. The first one is: the energy levels structure of Ce:LaAlO₃ is very similar to that of Ce:Lu₂(SiO₄)O which is a well-known scintillator. In the energy levels structure of Ce:LaAlO₃ and Ce:Lu₂(SiO₄)O, the lowest 5d energy level of Ce3+ is located below the bottom of the conduction band of host crystal and the other higher 5d energy levels of Ce³⁺ are located above the bottom of the conduction band of host crystal. The second one is: Ce:LaAlO₃ single crystal may not be suitable for scintillation application; by comparing the energy levels structures of Ce:LaAlO₃ and Ce:Lu₂(SiO₄)O, the large energy difference (1.13 eV) between the two lowest 5d energy levels of Ce³⁺ in LaAlO₃ is a crucial factor that causes the luminescence quenching.     

Effect of CaCO3 on hydration characteristics of C3A

Hydration products and morphology characteristics of C₃A (tricalcium aluminate)-CaCO₃-H₂O system were studied by means of XRD, DSC, FTIR spectrum analysis and SEM. The results indicate that, the new phases, i.e., C₃A·0.5CaCO₃·0.5Ca(OH)₂·11.5H₂O and C₃A·CaCO₃·11H₂O are found in this system due to the activity of CaCO₃; the formation of C₄AH₁₃ and C₂AH₈ is prohibited and the generation of C₃AH₆ is delayed in the early hydration process. C₃A·0.5CaCO₃·0.5Ca(OH)₂·11.5H₂O is not stable and will be totally transferred within 24 h; C₃A·CaCO₃·11H₂O exists stably once formation, and its flake-like crystalline phases in the early hydration transform to long rod shape, and to finally fine-needle at 28 d.