晶相组成可调的高活性可见光应答型二氧化钛纳米复合光催化材料的制备

采用新的化学溶液法,通过不同体积的钛酸四异丙酯的2-乙二醇单乙醚溶液与一定浓度的H₂O₂水溶液直接反应并对生成的钛过氧化配合物进行焙烧,制备了一系列TiO₂光催化剂. 表征发现,所得TiO₂样品为金红石和锐钛矿的纳米复合晶体,改变2-乙二醇单乙醚的体积可实现金红石相比例在0~96%广范围的调变.与商业二氧化钛P-25相比,所得的TiO₂紫外-可见光吸收谱出现明显红移,间隙能降低, 在可见光照射下,该样品对亚甲基蓝有良好的降解活性. 当2-乙二醇单乙醚的添加量为5 ml时,所得样品体相中金红石相比例接近50%,其光催化活性和吸附性能最好,可分别是P-25的3倍和5倍. 拉曼光谱结合X射线衍射等表征结果表明,该样品的表面仅含少量的金红石相. TiO₂纳米复合晶表面晶相的组成和分布对其光催化降解亚甲基蓝的活性及其吸附能力有直接的影响. 另外,TiO₂纳米复合晶的缺陷浓度也是增强其光吸收能力,提高其可见光光催化活性的原因之一.     

纳米TiO2的制备及对三甲胺气体的敏感性能

用硬脂酸凝胶法制备纳米TiO₂材料,并用XRD、TEM、IR对纳米晶的晶型、晶粒大小及形貌进行表征；用XPS分析不同晶型的纳米TiO₂表面吸附氧的情况，发现锐钛矿型纳米TiO₂比金红石型纳米TiO₂有较多的表面吸附氧. 检测了不同晶型纳米TiO₂对三甲胺（TMA）气体的敏感性能.结果表明锐钛矿型纳米TiO₂对TMA有较高的灵敏度. 对敏感性能的机理进行了讨论.     

V2O5-TiO2复合半导体光催化材料结构及光响应性能研究

采用溶胶凝胶法制备了V₂O₅-TiO₂复合半导体材料，通过Raman、XRD及UV-Vis DRS等实验方法研究了V₂O₅与TiO₂复合对材料表面组成、晶体结构以及光响应性能的影响。结果表明：钒加入后优先与TiO₂作用形成较为稳定的金红石型TiVO₄晶相，其中V⁴⁺是促进TiO₂发生相变的关键；随着钒加入量的增加，V₂O₅由表面高分散状态逐渐聚集形成晶相，并释放部分Ti⁴⁺使之形成锐钛矿型TiO₂晶相，使得体相中金红石型TiO₂的含量有所下降；复合后形成的TiVO₄晶相显著提高了材料对可见光的吸收率，并使其吸光域红移至460 nm左右。     

纳米TiO2-SiO2复合光催化剂的超临界流体干燥法制备及其光催化性能研究

本文以廉价无机盐Na₂SiO₃·9H₂O和TiCl₄溶液为原料,采用化学包覆结合超临界流体干燥(SCFD)法制备纳米级TiO₂-SiO₂复合光催化剂。利用XRD、TEM、NMR等手段对复合粉体进行了表征。结果表明,采用超临界流体干燥法可直接制得锐钛矿型TiO₂-SiO₂纳米复合光催化剂,其中SiO₂以单分散、无定形形式存在。以苯酚和邻苯二酚紫光催化降解为反应模型,考察了TiO₂-SiO₂复合光催化剂的催化性能。证明掺入适量SiO₂的TiO₂-SiO₂纳米复合光催化剂既减少了TiO₂的用量、降低了成本,又在某种程度上提高了TiO₂的光催化活性。SiO₂的引入可以有效抑制纳米粒子粒径的长大和晶相的转变,增强了二氧化钛纳米粒子的热稳定性。二氧化硅的最优掺杂量为15%(质量分数)。     

溶胶-凝胶-水热晶化法制备锐钛矿TiO2纳米膜的耐蚀性能

以钛酸正丁酯为前驱体, 采用溶胶-凝胶-水热晶化法在不锈钢(SS)表面制备TiO₂纳米膜. 利用X射线衍射(XRD)、Raman光谱、场发射扫描电子显微镜(SEM)、原子力显微镜(AFM)和俄歇电子能谱(AES)表征了TiO₂纳米膜的晶型、表面形貌和表面化学组成. 通过极化曲线和电化学阻抗谱(EIS)研究了TiO₂纳米膜的耐蚀性能. 170 °C下水热晶化制备的锐钛矿TiO₂与450 °C焙烧制备的锐钛矿TiO₂的结晶度类似, 但两种TiO₂薄膜的表面结构存在明显差异, 水热晶化法制备的TiO₂纳米膜在3.5% (w) NaCl溶液中的耐蚀性能优于焙烧法制备的.     

二氧化钛催化超声波损伤牛血清白蛋白的研究

利用紫外可见(UV-Vis)光谱和荧光(FL)光谱研究了二氧化钛(TiO₂)催化超声波照射对牛血清白蛋白(BSA)的损伤作用，同时对金红石型和锐钛矿型TiO₂的催化性能进行了比较，并探讨了照射时间，TiO₂加入量，溶液酸度，超声波功率和离子强度等因素对BSA分子损伤的影响。结果表明，金红石型TiO₂的催化效果明显好于锐钛矿型TiO₂。在一定条件下，BSA分子的损伤程度随着照射时间的延长、照射功率和溶液酸度的增大而增大，而TiO₂的加入量和离子强度对BSA分子损伤的影响则较为复杂。     

等离子体修饰磁载TiO2光催化剂性能研究

以化学共沉法制备的CoFe₂O₄纳米粒子为磁核,采用TiCl₄水解包覆技术制备磁载二氧化钛纳米复合粒子CoFe₂O₄ /TiO_x(TCF),利用低温等离子体技术修饰TCF制备了CoFe₂O₄/TiO₂(PTCF)纳米复合光催化剂。运用VSM(振动样品磁强计)技术对样品磁性能进行研究,结果表明：等离子体修饰后的复合材料仍具有较高的饱和磁化强度,可在外加磁场作用下实现催化剂在水中的分离与回收;样品的XRD、TEM和UV-Vis分析测试结果表明：等离子体修饰后的复合材料有锐钛矿型TiO₂存在;TEM谱图显示磁核CoFe₂O₄的平均粒径约为20 nm,TCF复合粒子的粒径约为30~40 nm,TiO₂包覆层的厚度为10~20 nm。与纯TiO₂相比PTCF样品对光的吸收拓展到整个紫外-可见区,扩大了光谱响应范围;对甲基橙溶液降解的光催化活性评价研究表明：TCF复合粒子等离子体修饰后的PTCF纳米复合光催剂的光催化活性明显提高。     

TiO2纳米纤维无纺布的制备及光催化性能研究

以聚乙烯吡咯烷酮(PVP)作为配位剂与钛酸正丁酯(Ti(C₄H₉O)₄)反应制得前驱体，再以乙醇为溶剂，CH3COOH作为催化剂，采用静电纺丝法制得PVP/TiO₂复合纳米纤维，经550 ℃、700 ℃和900 ℃焙烧后分别得到以锐钛矿型的TiO₂为主、以金红石型TiO₂为主和完全金红石晶型的TiO₂纳米纤维。对所制得的纳米纤维的结晶度、纯度和形貌，分别采用差热-热重分析(TG-DTA)、红外光谱(IR)、X射线粉末衍射(XRD)、扫描电镜(SEM)等进行了表征。光降解苯酚水溶液的实验结果表明，550 ℃下煅烧得到的以锐钛矿占主体的TiO₂纳米纤维，2 h使浓度为50 mg·L^-1苯酚水溶液的降解率超过85%，这充分说明这种TiO₂电纺纳米纤维具有良好的光催化性能。     

溶胶-凝胶法制备纳米TiO2/丝素复合膜及结构性能研究

用溶胶凝胶法制备不同比例纳米TiO₂改性再生蚕丝丝素蛋白复合膜. UV和AFM测试结果表明, 该丝素膜中纳米TiO₂均匀分散在丝素中, TiO₂粒径约为80 nm; 同时该丝素膜的结构和热性能用FTIR, XRD, EDS, TGA和DTG进行表征. XRD测试结果表明, 随着纳米TiO₂的加入, 复合丝素膜的结晶结构从Silk I向Silk II转化, 但当纳米TiO₂的加入超过一定量时, 又破坏复合丝素膜的结晶结构; FTIR和EDS测试结果表明, TiO₂与丝素形成较好的键合; TGA和DTG测试表明复合丝素膜的热转变温度相比于纯丝素膜有所提高.     

溶胶-凝胶法制备纳米TiO2/丝素复合膜及结构性能研究

用溶胶凝胶法制备不同比例纳米TiO₂改性再生蚕丝丝素蛋白复合膜. UV和AFM测试结果表明, 该丝素膜中纳米TiO₂均匀分散在丝素中, TiO₂粒径约为80 nm; 同时该丝素膜的结构和热性能用FTIR, XRD, EDS, TGA和DTG进行表征. XRD测试结果表明, 随着纳米TiO₂的加入, 复合丝素膜的结晶结构从Silk I向Silk II转化, 但当纳米TiO₂的加入超过一定量时, 又破坏复合丝素膜的结晶结构; FTIR和EDS测试结果表明, TiO₂与丝素形成较好的键合; TGA和DTG测试表明复合丝素膜的热转变温度相比于纯丝素膜有所提高.     

Ba3 (VO4)2-K2 Ba(MoO4)2 and Pb3 (VO4)2-K2 Pb(MoO4)2 systems

Phase equilibria in the Ba₃(VO₄)₂-K₂Ba(MoO₄)₂ and Pb3(VO₄)₂-K₂Pb(MoO₄)₂ systems have been investigated. In the first system, a continuous series of substitutional solid solutions with the palmierite structure is formed, and in the second one, the polymorphic transition in lead orthovanadate at 100°C restricts the extent of the palmierite-type solid solution to 10–100 mol % K₂Pb(MoO₄)₂. Original Russian Text ? V.D. Zhuravlev, Yu.A. Velikodnyi, A.S. Vinogradova-Zhabrova, A.P. Tyutyunnik, V.G. Zubkov, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 10, pp. 1746–1748.     

Investigation of phase equilibria in the systems K2SO4Sc2(SO4)3, Rb2SO4Sc2(SO4)3 and Cs2SO4Sc2(SO4)3

Phase diagrams of the systems K₂SO₄Sc₂(SO₄)₃, Rb₂SO ₄Sc₂(SO₄)₃ and Cs₂SO₄ Sc₂(SO₄)₃ have been investigated by X-ray diffraction phase analysis and differential thermal analysis techniques. A salient feature of all the systems is the formation of M₃Sc(SO₄)₃, which melt incongruently, and MSc(SO₄)₂, which on heating decompose in the solid state.     

Synthesis and molecular structures of heptafluoroisopropylated fullerenes: C60(i-C3F7)8, C60(i-C3F7)6, and C60(CF3)2(i-C3F7)2

One isomer of C₆₀(i-C₃F₇)₈, three isomers of C₆₀(i-C₃F₇)₆, and the first mixed perfluoroalkylated fullerene, C₆₀(CF₃)₂(i-C₃F₇)₂, have been isolated by HPLC from a mixture prepared by reaction of C₆₀ with heptafluoroisopropyl iodide in a glass ampoule at 260-290 °C. The molecular structures of the four new compounds have been determined by means of X-ray single crystal diffraction partially also by use of synchrotron radiation. Theoretical calculations at the DFT level of theory have been employed to rationalize the energetics of isomers and of C₆₀-R_f binding.     

Syntheses, structures, and properties of Ag4(Mo2O5)(SeO4)2(SeO3) and Ag2(MoO3)3SeO3

Ag₄(Mo₂O₅)(SeO₄)₂(SeO₃) has been synthesized by reacting AgNO₃, MoO₃, and selenic acid under mild hydrothermal conditions. The structure of this compound consists of cis-MoO₂²⁺ molybdenyl units that are bridged to neighboring molybdenyl moieties by selenate anions and by a bridging oxo anion. These dimeric units are joined by selenite anions to yield zigzag one-dimensional chains that extended down the c-axis. Individual chains are polar with the C₂ distortion of the Mo(VI) octahedra aligning on one side of each chain. However, the overall structure is centrosymmetric because neighboring chains have opposite alignment of the C₂ distortion. Upon heating Ag₄(Mo₂O₅)(SeO₄)₂(SeO₃) looses SeO₂ in two distinct steps to yield Ag₂MoO₄. Crystallographic data: (193 K; MoKα, λ=0.71073 Å): orthorhombic, space group Pbcm, a=5.6557(3), b=15.8904(7), c=15.7938(7) Å, V=1419.41(12), Z=4, R(F)=2.72% for 121 parameters with 1829 reflections with I>2σ(I). Ag₂(MoO₃)₃SeO₃ was synthesized by reacting AgNO₃ with MoO₃, SeO₂, and HF under hydrothermal conditions. The structure of Ag₂(MoO₃)₃SeO₃ consists of three crystallographically unique Mo(VI) centers that are in 2+2+2 coordination environments with two long, two intermediate, and two short bonds. These MoO₆ units are connected to form a molybdenyl ribbon that extends along the c-axis. These ribbons are further connected together through tridentate selenite anions to form two-dimensional layers in the [bc] plane. Crystallographic data: (193 K; MoKα, λ=0.71073 Å): monoclinic, space group P2₁/n, a=7.7034(5), b=11.1485(8), c=12.7500(9) Å, β=105.018(1) V=1002.7(2), Z=4, R(F)=3.45% for 164 parameters with 2454 reflections with I>2σ(I). Ag₂(MoO₃)₃SeO₃ decomposes to Ag₂Mo₃O₁₀ on heating above 550 °C.     

Phase transitions in Ca3(BN2)2 and Sr3(BN2)2

α-Ca₃(BN₂)₂ crystallizes in the cubic system (space group: ) with one type of calcium ions disordered over of equivalent (8c) positions. An ordered low-temperature phase (β-Ca₃(BN₂)₂) was prepared and found to crystallize in the orthorhombic system (space group: Cmca) with lattice parameters: , , and . Structure refinements on the basis of X-ray powder data have revealed that orthorhombic β-Ca₃(BN₂)₂ corresponds to an ordered super-structure of cubic α-Ca₃(BN₂)₂. The space group Cmca assigned for β-Ca₃(BN₂)₂ is derived from by a group-subgroup relationship.DSC measurements and temperature-dependent in situ X-ray powder diffraction studies showed reversible phase transitions between β- and α-Ca₃(BN₂)₂ with transition temperatures between 215 and 240 °C.The structure Sr₃(BN₂)₂ was reported isotypic with α-Ca₃(BN₂)₂ () with one type of strontium ions being disordered over of equivalent (2c) positions. In addition, a primitive () structure has been reported for Sr₃(BN₂)₂. Phase stability studies on Sr₃(BN₂)₂ revealed a phase transition between a primitive and a body-centred lattice around 820 °C. The experiments showed that both previously published structures are correct and can be assigned as α-Sr₃(BN₂)₂ (, high-temperature phase), and β-Sr₃(BN₂)₂ (, low-temperature phase).A comparison of Ca₃(BN₂)₂ and Sr₃(BN₂)₂ phases reveals that the different types of cation disordering present in both of the cubic α-phases () have a directing influence on the formation of two distinct (orthorhombic and cubic) low-temperature phases.     

Luminescence properties of efficient X-ray phosphors of YBa3B9O18, LuBa3(BO3)3, α-YBa3(BO3)3 and LuBO3

The samples of YBa₃B₉O₁₈, LuBa₃(BO₃)₃, α-YBa₃(BO₃)₃ and LuBO₃ powders have been synthesized by the solid-state reaction methods at high temperature and their X-ray excited luminescent properties were investigated. All the studied materials show a broad emission band in the wavelength range of 300-550 nm with the peak centers at about 385 nm for YBa₃B₉O₁₈ and LuBa₃(BO₃)₃, 415 nm for α-YBa₃(BO₃)₃ and 360 nm for LuBO₃ powders, respectively. Even though those compounds have the different atomic structures, they have the common structural feature of each yttrium or lutetium ion bonded to six separate BO₃ groups, i.e., octahedral RE(BO₃)₆ (RE=Lu or Y) moiety. This octahedral RE(BO₃)₆(RE=Lu or Y) moiety seems to be an important structural element for efficient X-ray excited luminescence of those compounds, as are the edge-sharing octahedral TaO₆ chains for tantalate emission.     

Vapour-liquid equilibrium data for the systems C2H6 + N2, C2H4 + N2, C3H8 + N2, and C3H6 + N2

High pressure vapour-liquid equilibrium data for the C₂H₆ + N₂, C₂H₄ + N₂, C₃H₈ + N₂, and C₃H₆ + N₂ systems are presented. The data are obtained isothermally in the range from 200 K to 290 K. For each point of data, temperature, pressure and liquid and vapour phase mole fractions are measured.Values for the vapour phase mole fractions are calculated from the obtained pressure, temperature and liquid phase mole fractions. The calculated values are compared with the experimental results, and it is found that the average mean deviation between calculated and experimental mole fractions is less than 0.009 for the systems considered in this work.     

A new three-dimensional cobalt phosphate: Co5(OH2)4(HPO4)2(PO4)2

A three-dimensional (3D) cobalt phosphate: Co₅(OH₂)₄(HPO₄)₂(PO₄)₂ (1), has been synthesized by hydrothermal reaction and characterized by single-crystal X-ray diffraction, thermogravimetric analysis, and magnetic techniques. The title compound is a template free cobalt phosphate. Compound 1 exhibits a complex net architecture based on edge- and corner-sharing of CoO₆ and PO₄ polyhedra. The magnetic susceptibility measurements indicated that the title compound obeys Curie-Weiss behavior down to a temperature of 17 K at which an antiferromagnetic phase transition occurs.     

Synthesis and structural investigation of the compounds containing HF2 anions: Ca(HF2)2, Ba4F4(HF2)(PF6)3 and Pb2F2(HF2)(PF6)

Three new compounds Ca(HF₂)₂, Ba₄F₄(HF₂)(PF₆)₃ and Pb₂F₂(HF₂)(PF₆) were obtained in the system metal(II) fluoride and anhydrous HF (aHF) acidified with excessive PF₅. The obtained polymeric solids are slightly soluble in aHF and they crystallize out of their aHF solutions. Ca(HF₂)₂ was prepared by simply dissolving CaF₂ in a neutral aHF. It represents the second known compound with homoleptic HF environment of the central atom besides Ba(H₃F₄)₂. The compounds Ba₄F₄(HF₂)(PF₆)₃ and Pb₂F₂(HF₂)(PF₆) represent two additional examples of the formation of a polymeric zigzag ladder or ribbon composed of metal cation and fluoride anion (MF⁺)_n besides PbF(AsF₆), the first isolated compound with such zigzag ladder. The obtained new compounds were characterized by X-ray single crystal diffraction method and partly by Raman spectroscopy. Ba₄F₄(HF₂)(PF₆)₃ crystallizes in a triclinic space group P1¯ with a=4.5870(2) Å, b=8.8327(3) Å, c=11.2489(3) Å, α=67.758(9)°, β=84.722(12), γ=78.283(12)°, V=413.00(3) Å³ at 200 K, Z=1 and R=0.0588. Pb₂F₂(HF₂)(PF₆) at 200 K: space group P1¯, a=4.5722(19) Å, b=4.763(2) Å, c=8.818(4) Å, α=86.967(10)°, β=76.774(10)°, γ=83.230(12)°, V=185.55(14) ų, Z=1 and R=0.0937. Pb₂F₂(HF₂)(PF₆) at 293 K: space group P1¯, a=4.586(2) Å, b=4.781(3) Å, c=8.831(5) Å, α=87.106(13)°, β=76.830(13)°, γ=83.531(11)°, V=187.27(18) Å³, Z=1 and R=0.072. Ca(HF₂)₂ crystallizes in an orthorhombic Fddd space group with a=5.5709(6) Å, b=10.1111(9) Å, c=10.5945(10) Å, V=596.77(10) Å³ at 200 K, Z=8 and R=0.028.     

Synthesis and crystal structure of gallosilicate- and aluminogermanate tetrahydroborate sodalites Na8[GaSiO4]6(BH4)2 and Na8[AlGeO4]6(BH4)2

Tetrahydroborate enclathrated sodalites with gallosilicate and aluminogermanate host framework were synthesized under mild hydrothermal conditions and characterized by X-ray powder diffraction and IR spectroscopy. Crystal structures were refined in the space group P-43n from X-ray powder data using the Rietveld method. Na₈[GaSiO₄]₆(BH₄)₂: a=895.90(1) pm, V=0.71909(3)×10⁻⁶ nm³, R_P=0.074, R_B=0.022, Na₈[AlGeO₄]₆(BH₄)₂: a=905.89(2) pm, V=0.74340(6)×10⁻⁶ nm³, R_P=0.082, R_B=0.026. The tetrahedral framework T-atoms are completely ordered in each case and the boron atoms are located at the centre of the sodalite cages. The hydrogen atoms of the enclathrated anions were refined on x, x, x positions, restraining them to boron-hydrogen distances of 116.8 pm as found in NaBD₄.The IR-absorption spectra of the novel phases show the typical bands of the tetrahedral group as found in the spectrum of pure sodium boron hydride.The new sodalites are discussed as interesting -containing model compounds which could release pure hydrogen.