硅酸铋(BSO)纳米粉体的制备与表征

Bismuth silicate nanopowders were prepared by the sol-gel method. Tetraethyl orthosilicate (TEOS) and Bi₂O₃ were used as the starting materials. The precursors were heat-treated at 750℃ for 2 h. The size distribution of Bi₄Si₃O₁₂ nanopowders is 40～100 nm. The TG-DTA curves, the XRD patterns and the TEM microphotograph of Bi₄Si₃O₁₂ are discussed. Compared with crystal materials, the excitation spectra and the emission spectra of Bi₄Si₃O₁₂ nanopowders indicate blue shift.     

Structural characterization of amorphous and nanostructured bismuth silicate xerogels

Bismuth silicate xBi₂O₃·(1 − x)SiO₂ xerogels, 0 ≤ x ≤ 0.5, doped with gadolinium have been synthesized by sol–gel method. The study aims to evidence by X-ray diffraction (XRD), electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) the structural changes in amorphous Bi₂O₃–SiO₂ xerogels, function of Bi₂O₃ content and heat treatment. As was proved by XRD, nanostructured samples were obtained after 30 min heat treatment at 400 °C of the as-prepared samples with x > 0, in the mainly amorphous matrices nanocrystals of Bi_5.6Si_0.5O_9.4 phase being developed. The dimension of the nanocrystallites are function of the bismuth content, and vary from few nanometers to 25 nm for samples with x = 0.14 and x = 0.5 respectively. The local order around silicon, reflected by 29Si MAS NMR spectra, is less dependent on both composition and thermal history of the samples, showing that an amorphous silicon rich phase is present in all samples. The changes in the local order around Gd³⁺ ions, as reflected by the EPR spectra dependence on composition and especially on the heat treatment, support the assumption that a part of these paramagnetic ions is incorporated in the bismuth rich phase.     

电化学方法制备超细氧化铋粉末

超细氧化铋用途广泛。目前超细氧化铋的制备一般通过四个途径;一、机械粉碎法,可以获得粒径1μm的细粉,但在粉碎的过程中易混入杂质;二、熔融喷雾法,该法可以在短时间(45—48s)内获得超细Bi2O3,但均匀性差,氧化不易完全,生产过程有粉尘污染;三、通过水解氧化铋的     

Thermal stability and sintering behaviour of hydroxyapatite nanopowders

Hydroxyapatite (HA) nanopowders were synthesised following two different precipitation routes: (a) from calcium nitrate and diammonium hydrogen phosphate solutions and (b) from calcium hydroxide suspension and phosphoric acid solution. The influence of precipitation process, concentration, and synthesis temperature on HA particle size and morphology, phase composition, thermal stability, and sintering behaviour was investigated by means of: thermogravimetry and differential thermal analysis (TG-DTA), induced coupled plasma–atomic emission spectroscopy (ICP-AES), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), electron microscopy (TEM, SEM) and dilatometry.     

AgNi双金属改性多面体钒酸铋的制备及光催化性能

采用简单的水热法制备了多面体钒酸铋（BVO）材料,又通过化学还原法首次在BVO上原位合成了一种小尺寸的AgNi双金属助催化剂并研究了其光催化性能。采用X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、紫外可见漫反射光谱（UV-Vis DRS）、X射线光电子能谱（XPS）、光致发光（PL）光谱、N₂吸附-脱附等手段对制备的AgNi/BVO材料的理化性能进行了表征。结果表明,AgNi双金属广泛负载在这种特殊形貌的BVO多面体表面,大大增加了金属的附着位点,同时AgNi负载也提高了BVO的结晶性。银表面等离子体谐振效应与镍的共格界面效应增强了BVO催化剂对可见光的吸收,增强了光生电子的分离,提高了光催化活性。光催化降解MB （亚甲基蓝）实验表明,当Ag、Ni的质量比为3∶1时,AgNi/BVO的催化活性最高,在可见光照射下其反应速率常数是BVO的5.4倍,该光催化剂在4次循环后仍能保持良好的光催化活性。     

Structural interpretation on silicate network of various silicate minerals by LMMS analysis

Silicates have several kinds of silicate tetrahedral network. Thirteen kinds of silicate minerals with 5 kinds of network structures have been analyzed with laser microprobe mass spectrometry (LMMS) and their spectra showed characteristic patterns according to their network structures. The Si-O fragment ions can be expressed as SiO _n (n 4) for nesosilicates, Si _m O_3m±1 for inosilicates, Si _m O_{5/2m±(m/2+1)} for phyllosilicates and Si _m O_2m±(m+1) for tectosilicates. The Si-O system in the fragment ions in LMMS spectra suggests the pattern of network of tetrahedral SiO₄.     

AgNi双金属改性多面体钒酸铋的制备及光催化性能

采用简单的水热法制备了多面体钒酸铋(BVO)材料,又通过化学还原法首次在BVO上原位合成了一种小尺寸的AgNi双金属助催化剂并研究了其光催化性能。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、紫外可见漫反射光谱(UV-Vis DRS)、X射线光电子能谱(XPS)、光致发光(PL)光谱、N2吸附-脱附等手段对制备的AgNi/BVO材料的理化性能进行了表征。结果表明,AgNi双金属广泛负载在这种特殊形貌的BVO多面体表面,大大增加了金属的附着位点,同时AgNi负载也提高了BVO的结晶性。银表面等离子体谐振效应与镍的共格界面效应增强了BVO催化剂对可见光的吸收,增强了光生电子的分离,提高了光催化活性。光催化降解MB (亚甲基蓝)实验表明,当Ag、Ni的质量比为3∶1时,AgNi/BVO的催化活性最高,在可见光照射下其反应速率常数是BVO的5.4倍,该光催化剂在4次循环后仍能保持良好的光催化活性。     

Preparation of Nano‐bismuth with Different Particle Sizes and the Size Dependent Electrochemical Thermodynamics

Nano‐bismuth has excellent electrochemical properties. However, it is still unclear how the particle size of nano‐bismuth influences its electrochemical thermodynamic properties. In this paper, spherical bismuth nanoparticles with different particle sizes were prepared by solvothermal method; the electrode potentials, the temperature coefficients of the electrode potentials and the thermodynamic functions of reaction for nano‐bismuth electrodes with different particle sizes at different temperatures were determined; and the effects of particle size on the electrode potential, the temperature coefficient and the thermodynamic functions were discussed. The experimental results show that particle size of bismuth nanoparticles has a significant influences on the electrochemical thermodynamic properties. The standard electrode potential of the nano‐bismuth electrode with a diameter of 39.9 nm was 0.009 V lower than that of the ordinary standard electrode (0.308 V); the temperature coefficient of the electrode potential with a diameter of 39.9 nm was nearly double that of 85.9 nm. With the particle sizes decrease, the standard molar Gibbs energy of reaction, the standard molar enthalpy of reaction, the standard molar entropy of reaction, the molar reversible reaction heat and the temperature coefficient increase; and these quantities are linearly related to the reciprocal of the particle diameter.     

Concentration dependence of spectroscopic properties and energy transfer analysis in Nd3+ doped bismuth silicate glasses

A detailed investigation on 1.06 μm spectroscopic properties as a function of Nd³⁺ ions concentration in bismuth silicate glasses is reported. Judd–Ofelt analysis indicated that Nd₂O₃ has no substantial influence on glass structure. Based on the Judd–Ofelt intensity parameters, several radiative properties such as radiative transition probability, radiative lifetime, branching ratio and emission cross-section of Nd³⁺ ions have been derived. The 1.06 μm emission intensity increases firstly and then attains maximum at 0.5 mol% Nd₂O₃ and decreases with further increase of dopant concentration. The luminescence quenching behavior at higher Nd³⁺ concentration has been ascribed to the hopping migration assisted cross relaxation mechanism. The high emission cross section (2.33 × 10⁻²⁰ cm²) and large quantum efficiency (90.7%) suggests their potential for compact 1.06 μm lasers applications.     

Preparation of sodium borosilicates using sodium silicate and boric acid

The gelling behaviour of an aqueous sodium silicate solution with boric acid was investigated for different initial compositions and solid sodium borosilicate samples were obtained by drying the gels at 100°C, 225°C and 450°C. The chemical composition, dissolution, pH, loose-packed bulk density, B.E.T. surface area, moisture, size distribution and XRD/IR patterns of the sodium borosilicate particles were determined. The minimum gelling times were observed at pH values between 9–10 and although no gels were obtained using HCl at pH = 11, the silicate solution was gelled with boric acid suggesting borate ions promote the formation of siloxane network and behave as a crosslinking agent.     

Preparation of bismuth sulfide nanoparticles as targeted biocompatible nano-radiosensitizer and carrier of methotrexate

In this study, Bi₂S₃@BSA–Bio–MTX nanoparticles (NPs) were synthesized for the first time by bovine serum albumin (BSA)-mediated biomineralization (Bi₂S₃@BSA NPs) followed by covalent bonding of biotin (Bio) and methotrexate (MTX) on the surface of the Bi₂S₃@BSA NPs via carbodiimide chemistry. The synthesized NPs were globular and exhibited uniform morphology with a hydrodynamic diameter of 107.6 ± 6.81 nm (mean ± standard deviation) and zeta potential of −20.9 ± 2.18 mV. Drug release from Bi₂S₃@BSA–Bio–MTX NPs indicated an enzyme-dependent release pattern. The in vitro biocompatibility of NPs was confirmed by investigating their cytotoxicity against the HEK-293 cell line and hemolysis assay test, whereas the in vivo biocompatibility of the NPs was evaluated and confirmed by the lethal dose 50 (LD₅₀) test. To evaluate the in vitro anticancer activity of the functionalized NPs and MTX, their cytotoxic effects was assessed against 4T1 cancer cells by 5-dimethylthiazol-z-yl)-2,5-diphenyltetrazolium bromide (MTT) assay with and without X-ray radiation. Results showed that Bi₂S₃@BSA–Bio–MTX NPs have excellent anticancer activity, especially following X-ray radiation.     

Synthesis and characterization of antimony trichloride and bismuth trichloride complexes with valine

Two compounds of antimony trichloride and bismuth trichloride with valine are synthesized by solid phase synthesis at room temperature. Their compositions, determined by element analysis, are Sb(C₅H₁₀O₂N)₃·2H₂O and Bi(C₅H₁₀O₂N)₂Cl·0.5H₂O. The crystal structure of antimony complex with valine belongs to triclinic system and its lattice parameters are: a=0.9599 nm, b=1.5068 nm, c=1.9851 nm, α=92.270, β=95.050, γ=104.270. The crystal structure of bismuth complex with valine belongs to monoclinic system and its lattice parameters are: a=1.6012 nm, b=1.8941 nm, c=1.839 nm, β=99.73°. The far-infrared spectra and infrared spectra show that the amino group and carboxyl of valine may be coordinated to antimony and bismuth, respectively, in two compounds. The TG-DSC results also reveal that the complexes were formed.     

8-羟基喹啉铋的合成、表征与光谱研究

8-羟基喹啉及其衍生物是以喹啉环为母体的化合物,具有较大的共轭π键结构,吸光系数高,分子中处于邻位的羟基O和杂环N原子上都含有孤对电子,与金属离子易形成双齿配位具有特殊光学特性的五员环配合物[1-3].金属铋被认为是安全稳定的绿色重金属元素,其化合物除了广泛应用于医学外,其配合物的用途正日益被开发[4-5].本文用元素分析仪、XRD、热重-差热、红外等手段对由8-羟基喹啉形成的铋配合物的组成和结构进行表征.并初步研究了生成物的光致发光性和紫外吸收光谱.     

A chemical route for the synthesis of cubic bismuth zinc niobate pyrochlore nanopowders

Cubic bismuth zinc niobate pyrochlore (base composition (Bi_1.5Zn_0.5)(Zn_0.5Nb_1.5)O₇) powders were successfully prepared by a chemical method. The formation mechanism of the pyrochlore phase was investigated by TG-DSC, FT-IR, Raman, and X-ray diffraction (XRD). The optical bandgap for the powders treated at temperatures ranging from 500 to 700 °C is 3.0-3.1 eV, indicating low crystallization temperature for the pyrochlore phase. No detectable intermediary phases as BiNbO₄ or a pseudo-orthorhombic pyrochlore were observed at any time and the cubic-BZN phase was already formed after thermal treatment at temperatures as low as 500 °C. The phase formation study reveals that a well-crystallized single-phased nanopowder is obtained after calcination at 700 °C, indicating that the chemical synthesis conferred a higher chemical homogeneity and reactivity on the powder, modifying the crystallization mechanism.     

Two new bismuth salts with succinic acid: synthesis,structural, spectroscopic and thermal characterization

Two novel bismuth succinate hydrates, namely, poly[[diaqua(μ₃-butane-1,4-dicarboxylato)hemi(μ-butane-1,4-dicarboxylato)bismuth] monohydrate], {[Bi(C₄H₄O₄)_1.5(H₂O)₂]·H₂O}_n ( 1 ), and poly[[μ-aqua-aqua(μ₃-butane-1,4-dicarboxylato)(μ-butane-1,4-dicarboxylato)-μ-oxido-dibismuth] monohydrate], {[Bi₂(C₄H₄O₄)₂O(H₂O)₂]·H₂O}_n ( 2 ), have been synthesized. Their crystal structures were determined by single-crystal X-ray diffraction and the compounds were characterized by IR and Raman spectroscopy, powder X-ray diffraction and thermal analysis. The crystal structure analysis revealed that the compounds are coordination polymers, with 1 having a two-dimensional layered structure and 2 displaying a three-dimensional (3D) framework. Fully deprotonated succinate anions (C₄H₄O₄²⁻) in two different conformations (trans and gauche) are included in their composition. The Bi³⁺ cations are surrounded by O atoms from the carboxylate groups of succinate anions and aqua ligands. BiO₉ coordination polyhedra in 1 are connected in pairs by edges. These pairs are bound together by bridging succinate ligands to form layers. Bismuth coordination polyhedra of two different types (BiO₉ and BiO₇) in 2 are connected by edges to form infinite ribbons. Ribbons of polyhedra with bridging succinate ligands form a 3D polymeric structure.     

Preparation of bismuth telluride thin film by electrochemical atomic layer epitaxy (ECALE)

Thin-layer electrochemical studies of the underpotential deposition (UPD) of Bi and Te on cold rolled silver substrate have been performed. The voltammetric analysis of underpotential shift demonstrates that the initial Te UPD on Bi-covered Ag and Bi UPD on Te-covered Ag fitted UPD dynamics mechanism. A thin film of bismuth telluride was formed by alternately depositing Te and Bi via an automated flow deposition system. X-ray diffraction indicated the deposits of Bi₂Te₃. Energy Dispersive X-ray Detector quantitative analysis gave a 2: 3 stoichiometric ratio of Bi to Te, which was consistent with X-ray Diffraction results. Electron probe microanalysis of the deposits showed a network structure that results from the surface defects of the cold rolled Ag substrate and the lattice mismatch between substrate and deposit. Translated from Chinese Journal of Applied Chemistry, 2005, 22 (11) (in Chinese)     

Physicochemical features of formation of silicate porous mesophases

Silicate mesoporous mesophases analogous to SBA-3 or MCM-41 with the hexagonal (honeycomb) structure can be synthesized in a moderately acidic region (pH ∼2.5—5). The synthesis was carried out using aqueous solutions of sodium silicate and a surfactant of the alkyltrimethylammonium bromide type as the starting precursors. For Part 4, see Ref. 1. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 29–34, January, 2008.     

Heat capacity, enthalpy and entropy of strontium bismuth niobate and strontium bismuth tantalate

The heat capacities and enthalpy increments of strontium bismuth niobate SrBi₂Nb₂O₉ (SBN) and strontium bismuth tantalate SrBi₂Ta₂O₉ (SBT) were measured by the relaxation method (2–150 K), Calvet-type heat-conduction calorimetry (305–570 K) and drop calorimetry (773–1373 K). The temperature dependences of non-transition heat capacities in the form C_pm = 324.47 + 0.06371T − 5.0755 × 10⁶/T² J K⁻¹ mol⁻¹ (298–1400 K) and C_pm = 320.22 + 0.06451T − 4.7001 × 10⁶/T² J K⁻¹ mol⁻¹ (298–1400 K) were derived for SBN and SBT, respectively, by the least-squares method from the experimental data. Furthermore, the standard molar entropies at 298.15 K S_m°(SBN)=327.15±0.80 and S_m°(SBT)=339.23±0.72 J K⁻¹ mol⁻¹ were evaluated from the low-temperature heat capacity measurements.