化学浴沉积法制备高取向钒酸铋薄膜

Highly oriented BiVO₄ films were synthesized on glass substrates by modified chemical bath deposition (CBD). The influence of the deposition parameters as temperature and time of deposition on the rate of process and the quality of BiVO₄ films was studied by XRD, Raman Spectroscopy and SEM. The film deposited at 90 ℃ for 12 h was dense and uniform. The BiVO₄ thin film under this optimal depositing conditions was consisted of octagonal crystalline grains in a narrow size distribution with an average size of about 7 μm, showing a (004) preferential orientation.     

在LaNiO3-Pt复合电极上Pb(Zr，Ti)O3铁电薄膜及其成分梯度薄膜的制备和研究

LaNiO₃(LNO) thin films were prepared on Pt(111) / Ti / SiO₂/ Si substrate by metal-organic decomposition (MOD) method. Pb(Zr,Ti)O₃ ferroelectric thin films and their compositionally graded thin films were prepared on LNO / Pt / Ti / SiO₂ /Si substrates by Sol-gel method. The composition depth profile of a typical up-graded film was determined by using a combination of Auger Electron Spectroscopy (ASE) and Ar Ion Etching. The results confirm that the processing method produces graded composition changes. XRD analysis showed that the graded thin films possessed composite structure of tetragonal and rhombohedral. The dielectric constants of Up-graded and Down-graded thin films were higher than that of each thin film unit. The dielectric constants were 277 and 269 at 10 kHz, respectively. The loss tangents were 0.019 and 0.018 at 10 kHz, respectively. The Hysteresis loops showed that the remanent polarizations of graded thin films were higher than that of each thin film unit, but the coercive fields were smaller. The remanent polarizations of Up-graded and Down-graded thin films were 30.06 and 26.96 μC·cm^-2, respectively. The coercive fields were 54.14, 54.23 kV·cm^-1, respectively. The pyroelectric coefficients of Up-graded and Down-graded thin films were 4.62, 2.51×10^-8 C·cm^-2·K^-1 at room temperature, respectively. They were higher than that of each thin film unit.     

电化学沉积技术制备LiNiO2薄膜及表征

Well-crystallized LiNiO₂ thin films were prepared directly on nickel substrates in LiOH solution by constant current electrochemical deposition technique at 95 ℃. The as-prepared LiNiO₂ thin films were characterized by using XRD, SEM and XPS, and the results reveal that the as-prepared LiNiO₂ thin films are dense and uniform in surface and show hexagonal structure. The influence of processing parameters such as reaction temperature, duration, electrical current density as well as the concentration of LiOH solution on the structure and morphologies of as-prepared LiNiO₂ thin films were studied，and the preferable electrochemical processing conditions for preparing LiNiO₂ thin films were suggested.     

MgFe2O4纳米粉体的水热合成及其表征(英)

MgFe₂O₄ nanoparticles were hydrothermally synthesized at 150 ℃ using iron nitrate [Fe(NO₃)₃·9H₂O], magnesium nitrate [Mg(NO₃)₂·6H₂O] and sodium hydroxide (NaOH) as starting materials by carefully controlling the reaction conditions. The influences of several factors such as presence or absence of Na⁺, molar ratio of Fe³⁺ / Mg²⁺, concentration of mental ions, temperature and reaction time on resultant products were investigated in the hydrothermal process. The sample was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and its magnetic properties were measured using vibrating sample magnetometer (VSM).     

N2O活化的Fe/ZSM-5表面活性氧的表征(英)

Temperature-programmed reduction (H₂-TPR) was employed to quantitatively characterize the active oxygen species generated from a high Fe-loading Fe/ZSM-5 catalyst exposed to N₂O at 250 ℃. [Fe-O-Fe]²⁺ dimer was determined as the active iron complex for N₂O decomposition to produce the active oxygen. Reduction of Fe³⁺ to Fe²⁺ by H₂ in the dimer and removal of OH^- groups from Fe²⁺ dimer by heating Fe/ZSM-5 to 700 ℃ were the prerequisites for the formation of this active Fe complex. A linear correlation with a slope of 1.0 between the amount of [Fe-O-Fe]²⁺ and that of active oxygen species was observed. Maximum amount of active oxygen species can be generated by reducing Fe/ZSM-5 catalyst with H₂ at the temperatures over 500 ℃ and then heating the resulting product in Ar to 700 ℃, followed by N₂O exposure at 250 ℃. The ratio of the total number of oxygen atoms (Ode) deposited by interaction of [Fe-O-Fe]²⁺ with N₂O to the amount of [Fe-O-Fe]²⁺ was 2. However, not all the deposited oxygen atoms were active oxygen (O_a); the ratio of O_a and O_de was 0.5. The iron dimer complex composing active oxygen is a five-atom ion [Fe₂O₃]²⁺; the most probable structure is as follows:     

预氧化固气法合成LiNiO2的研究

LiNiO₂ was prepared by reaction of stoichiometric amounts of thoroughly-mixed LiOH·H₂O and preoxidation nanometer-scale Ni₃O₂(OH)₄ powders in O₂ at the temperature of 700℃ for 6h. The products were tested by XRD， XPS， SEM and electrochemistry methods. It was shown that product was LiNiO₂ single-phase， and the valence of nickel was +3; the average size of it was 40nm; its initial charge specific capacity is 168mAh·g^-1 and the coulomb efficiency is 90%; the second charge specific capacity is 160mAh·g^-1 and the coulomb efficiency is 96%.     

Eu3+掺杂SiO2-B2O3-NaF玻璃的制备及发光性质

The Eu-doped SiO₂-B₂O₃-NaF glass was prepared by sol-gel process, using tetraethoxy Silicane, boric acid and sodium fluoride as starting materials, 0.10 mol·L^-1 EuCl₃ solution as the dopant. The luminescent properties of Eu³⁺ doped SiO₂-B₂O₃-NaF phosphors were investigated. The phosphors showed prominent luminescence in pink, the strong emission of Eu³⁺ comes from electronic transition of ⁵D₀- ⁷F₁（591 nm）and ⁵D₀- ⁷F₂（615 nm）,which derived from two transition modes of magnetic-dipole and electric-dipole .The peak intensity of 591nm in SiO₂-B₂O₃-NaF matrix is much stronger than it in the other matrixes, it means that SiO₂-B₂O₃-NaF has sensitization on the transition of ⁵D₀- ⁷F₁ (Eu³⁺). If there are broad bonds in the range of 275～380 nm in the excitation spectrum of Eu³⁺ -doped SiO₂-B₂O₃-NaF glass, the emission peak intensity should be intensified. It is because the electron migration CT band of O^2--Eu³⁺. For all Eu³⁺ concentrations used, the investigation found that when the mass of fraction got to 29.19×10^-3, the luminescence intensity reached the summit. And there is a phenomenon of concentration quenching. Investigation with the same concentration of Eu³⁺ at different annealed temperature, we found that the sample annealed at 400 ℃, the luminescence intensity achieved its maximum value, and Eu³⁺ in this matrix had a phenomenon of temperature quenching. The structural characterization of these luminescent materials was carried by used XRD and TEM. The result showed that the phosphor was in amorphous phase.     

CexPr1-xO2-δ复合氧化物的XRD和Raman表征

A series of Ce_xPr_1-xO_2-δ mixed oxides were synthesized by sol-gel method and characterized by Raman and XRD techniques. When x value was changed from 1.0 to 0.5, only a cubic phase CeO₂ was observed. The samples were very well crystallized on decreasing x from 0.50 to 0.99. For Ce_xPr_1-xO_2-δ samples 465 cm^-1 and 1 150 cm^-1 Raman peaks are attributed to the Raman active F_2g mode of CeO₂. The broad peak at about 570 cm^-1 in the region of 0.3 ≤x≤ 0.99 can be linked to lattice defects resulting in oxygen vacancies. The new band at about 195 cm^-1 may be attributed to the asymmetric vibration caused by the formation of oxygen vacancies. Calcination temperatures had great effect on the peak intensity for CeO₂ but less effect on Ce_0.8Pr_0.2O_2-δ in Raman spectra. It might be due to the transformation of the colors for the mixed oxides, the insertion of Pr atom into the ceria lattice could enhance the sintering resistance and thermal stability of the mixed oxides.     

H2在非晶态合金Ni40Fe40P20表面的吸附行为

With the level of B3LYP/Lanl2dz of density functional theory and advisable adsorption models designed, the adsorption properties of the most stable cluster of Ni₂Fe₂P were calculated, and four stable configurations with the adsorption of hydrogen were gained. The geometries and HOMO contributions of 3d orbital of metal atoms and energy level properties of adsorption configurations were concerned and their Infrared Spectrum were simulated and predicted. The bond lengths and bond orders and vibration frequencies concerned synthetically, the adsorption mechanisms of hydrogen molecular on amorphous alloys Ni₄₀Fe₄₀P₂₀ surfaces were discussed in the microcosmic aspect. The hydrogen molecules adsorbing on the clusters were dissociated. In the clusters′ Infrared Spectrums of hydrogen adsorption, there were the vibration peaks with the frequency less than 500 cm^-1 caused by metal atoms and other vibration peaks with the frequency more than 500 cm^-1 caused by hydrogen atoms. Compared with the energy level DOS of the clusters before and after adsorption, it was found, that the new adsorption activity sites generated after the adsorption of hydrogen, as well as easy way for metal atoms providing electrons and participating subsequence reactions were gained.     

Si5P6O25∶Tb3+的结构与荧光性质

Tb³⁺ ions were incorporated in P-Si matrix material through a sol-gel process. Luminescence properties of Tb³⁺ as a function of dopant， firing temperature， composition and structure of matrices were investigated. The gels synthesized by the reaction of P₂O₅ or H₃PO₄ with tetraethoxy silane and TbCl₃ as dopant were fired in air from the temperature 25～1000℃ to form P-Si crystalline phase. The crystal structure was determined by powder X-ray diffraction. Si₅O(PO₄)₆ were the only crystalline phase and belong to hexagonal crystal system. The emission of ⁵D₄-⁷F₅(～545nm) transition of Tb³⁺ in the P-Si system is composed of two peaks. The amount of doping Tb³⁺ varied from 0.664% to 1.644%， and no obvious concentration quenching was observed in this doping concentra-tion range. The intensity of Tb³⁺ emission increased with firing temperature increasing and becomes stable at 800～1000℃.     

Preparation of ZrO2-TiO2-CeO2 and Its Application in the Selective Catalytic Reduction of NO with NH3

TiO₂,ZrO₂-TiO₂,andZrO₂-TiO₂-CeO₂ were prepared by co-precipitation method and characterized by X-ray diffraction (XRD), specific surface area measurements (BET), temperature programmed desorption (NH₃-TPD), oxygen storage capacity (OSC), and temperature programmed reduction (H₂-TPR). The results showed that ZrO₂-TiO₂-CeO₂ exhibited large number of surface strong acid, possessed some oxygen storage capacity, and strong redox property. The three materials were used as supports and the monolith catalysts were prepared with 1% (w) V₂O₅ and 9% (w)WO₃ for selective catalytic reduction (SCR) of NO with ammonia in the presence of excessive O₂, and the results of catalytic activity showed that the catalyst used ZrO₂-TiO₂-CeO₂ as support yielded nearly 100% NO conversion at 275 °C at a gas hourly space velocity (GHSV) of 10000 h⁻¹, and it had the best catalytic activity and showed great potential for practical application.     

Thermal decomposition of Me3SnO2PCl2, Me2Sn(O2PCl2)2 and Ph3SnO2PCl2

TG and DTA studies on Me₃SnO₂PCl₂, Me₂Sn(O₂PCl₂)₂ and Ph₃SnO₂PCl₂ were carried out under dynamic argon atmosphere. The results show that the decomposition proceeds in different stages leading to the formation of Sn₃(PO₄)₂ as a stable product. This compound was characterized by IR spectroscopy. Decomposition schemes involving reductive elimination reactions were proposed.     

Li2O-TiO2-SiO2-P2O5和Li2O-TiO2-Al2O3-P2O5体系锂离子固体电解质的制备及性能研究

一些具有NASICON型网格结构的固体电解质具有高的电导率和好的稳定性,NASICON的意思是Na Super Ionic Conductor[1]。当NaZr2(PO4)3中P5 被Si4 部分取代时便可以得到具有NASICON结构的Na1 xZr2SixP3-xO12体系,其具有高的钠离子电导率。然而有相同结构的Li1 xZr2SixP3-xO12体系的离子电导率却很低,这是因为Li 半径太小,而NASICON三维网格结构的离子通道太大,两者不匹配而使电导率下降[2]。但当LiZr2(PO4)3中Zr4 被离子半径小些的Ti4 取代,所得LiTi2(PO4)3的通道就与Li 半径相匹配,适合于锂离子的迁移,从而使其电导率…     

Unusual phase characteristics in binary thallium telluride-metal telluride systems

The phase characteristics and some properties of alloys in the two most interesting of the binary thallium telluride systems (Tl₂Tl-Ag₂Te and Tb₂Te-Bi₂Te₃) are discussed and the phase diagrams of the systems are reviewed.     

(Cl2AlNH2)n和(H2AlNH2)n(n=1～5)簇结构及其热力学性质

用HF自洽场理论和密度泛函理论(DFT)的B3LYP方法,在6 31G水平上研究了低聚物(Cl2AlNH2)n和(H2AlNH2)n(n=1～5)簇的几何构型、电子结构和聚合反应热力学性质,比较了两个系列化合物中化学键的强度.结果表明,Cl2AlNH2和H2AlNH2分子为C2 (EC)平面型结构,其中Al－N为由一个σ键和一个键组成的双键.(Cl2AlNH2)n和(H2AlNH2)n(n=1～5)分子为Dnh对称,Al－N是典型的σ单键 .低聚物(Cl2AlNH2)n和(H2AlNH2)n的稳定性顺序分别为: 3 > 2 > 4> 5 > 1和8 > 7 > 9 > 11 > 6.     

Theoretical study of the triplet excited state of PtPOP and the exciplexes M-PtPOP (M = Tl, Ag) in solution and comparison with ultrafast X-ray scattering results

The [Pt₂(H₂P₂O₅)₄]⁴⁻ ions in the ground and excited states and the excited-state complexes M-[Pt₂(H₂P₂O₅)₄]³⁻ and M₂-[Pt₂(H₂P₂O₅)₄]²⁻ (M = Ag, Tl) were studied in solution with various density functional theory (DFT) functionals from Gaussian 09 and Amsterdam Density Functional (ADF) programs. Calculated results were compared with ultrafast X-ray solution scattering data. Time dependent DFT (TD-DFT) calculations with the B3PW91 functional and unrestricted open shell calculations with the mPBE functional produce good agreement with the experimental results. Compared to gas phase calculations, the surrounding solvent is found to play an important role to shorten the Pt-Pt and M-Pt (M = Ag, Tl) bond lengths, lowering the molecular orbital energies and influences the molecular orbital transitions upon excitation, which stabilizes the excited transient molecules in solution.     

TiO2/SnO2复合光催化剂的耦合效应

采用改进的sol gel技术制备TiO2/SnO2耦合型半导体光催化剂,利用XRD、气相色谱 仪、粒度仪和表面光电压装置等研究了耦合型半导体光催化机理和光催化效率的影响因素, 并通过降解甲醛探讨其在空气污染治理中的作用.实验结果表明,添加20 ％(mol) SnO2的复 合半导体光催化剂,其光催化效率比纯TiO2高一倍以上.据实验结果和粒子紧密堆积原理,提 出强耦合效应和弱耦合效应的光催化反应模型,并用此模型较好地解释了TiO2/SnO2复合型半 导体光催化剂的光催化效率随SnO2含量变化规律.     

Structure and electronic structure of [(CF3)2PN]2NVCl2, a molecule involving a planar six-membered ring (N3P2V)

Summary The SCF method is applied to determine the (gas phase) structure of [(CF₃)₂PN]₂NVCl₂, which agrees with the solid-state X-ray structure within typical errors of 2 pm and 2° in bond distances and angles. The electronic structure of atoms forming the ring is best described in terms of divalent N^– and tetravlent P⁺ with appreciable declocalization of nitrogen lone pairs into low-lying empty orbitals of neighbouring atoms P and V. No evidence for aromaticity of the ring system is found.     

Li2ZrO3材料吸收CO2性能的进一步研究

用不同结构的ZrO₂合成了一系列在高温下吸收CO₂的Li₂ZrO₃材料，并详细的研究了反应物质的物理和化学性质对生成物吸收CO₂性能的影响。采用SEM、XRD以及TG分析法分别进行了材料结构及其吸收CO₂性能的表征，并使用XPS法测定了材料表面的元素组成。实验结果表明，使用不同结构的ZrO₂合成的Li₂ZrO₃，其吸收CO₂的性能明显的不同。用ZrO₂(t)(四方)合成的Li₂ZrO₃吸收CO₂的速度快，在500 ℃下，20% CO₂（80%空气）的气氛中保持3h，其吸收量可达25（±0.6）%（wt），而以ZrO₂(m)(单斜)为原料制备的Li₂ZrO₃在上述吸收条件下重量仅增加9（±0.6）%（wt）。此外，实验结果还表明化学元素的掺杂对用ZrO₂(m)合成的Li₂ZrO₃的CO₂吸收速度及吸收容量影响较大。     

General Route to Synthesize Monodisperse Oxide (Hydroxide) Nanoparticles

Mono-dispersed oxide and hydroxide nanoparticles have been synthesized through the solvothermal process in alcohol-water mixtures. The products were characterized by powder x-ray diffraction (XRD) and scanning electron microscopy (SEM). Plate-like nanoparticles are obtained for Bi₂O_2.33, Fe₂O₃, and Cd(OH)₂, and spherical nanoparticles are obtained for SnO₂. The growth mechanism for the mono-dispersed nanoparticles has been preliminarily discussed.