Na4Ca(SO4)3复盐高温合成及温度对晶体形貌的影响

用高温合成法制备出硫酸钙复盐Na₄Ca(SO₄)₃，利用差热分析、X射线衍射、扫描电子显微分析等现代测试仪器研究了该复盐的反应历程。研究结果表明，其反应过程按CaSO₄+Na₂SO₄→(Na_0.8Ca_0.1)₂SO₄→Na₄Ca(SO₄)₃进行。Na₄Ca(SO₄)₃为高温稳定相，其最佳合成温度为800 ℃～1 100 ℃。育晶温度及时间对复盐形貌有明显影响，在1 000 ℃保温2 h后转到945 ℃育晶5 h,晶体生长较好。     

K3Na(FeO4)2的电合成及其晶体结构

本文采用间接法电合成出较高纯度的复盐K₃Na(FeO₄)₂晶体，用粉末XRD结构分析法对其晶体结构作了详细研究。用EDX和AAS确认了其化学式。结构分析表明，K₃Na(FeO₄)₂晶体属三方晶系，具有六方晶胞，空间群为P3m1(No.164)，Z=1,晶胞中有6个O位于6(i)位，O,Fe和K各自有2个位于2(d)位，1个K和Na分别位于1(b)位和1(a)位，晶胞参数a=0.583 3(1) nm,c=0.755 9(1) nm，D=2.824 g·cm^-3。同时晶胞中各原子间化学键键长得到确定。     

在CeO2-ZrO2中加入La2O3对改善单Pd三效催化剂性能的作用

浸渍法制备了CeO₂-ZrO₂-La₂O₃复合氧化物，用XRD、热分析（TG-DTA，DSC）、BET表面积、H₂-TPR等对合成样品进行表征，研究了La₂O₃的加入对CeO₂-ZrO₂和单钯Pd/CeO₂-ZrO₂/γ-Al₂O₃/蜂窝陶瓷催化剂性能和热稳定性的影响。结果表明，在CeO₂-ZrO₂-La₂O₃中，La的存在能促进CeO₂-ZrO₂固溶体的还原，提高贮氧能力；在Pd/CeO₂-ZrO₂/γ-Al₂O₃中加入La有利于提高催化剂的耐热稳定性，阻止γ-Al₂O₃在高温下的晶相转变，进一步稳定Al₂O₃的结构，保持其高的表面积。在贵金属Pd的负载量为1 g·L^-1的条件下，测定了Pd/CeO₂-ZrO₂-La₂O₃/γ-Al₂O₃/蜂窝陶瓷催化剂对CO、C₃H₈和NOx的三效催化净化活性。结果表明，在Pd/CeO₂-ZrO₂/Al₂O₃/蜂窝陶瓷催化剂中加入La₂O₃后，能明显地改善催化剂的低温活性和三效催化性能，经1 000 ℃老化10 h后，CO、C₃H₈和NO_x净化的起燃温度（T₅₀）分别为330 ℃、350 ℃和380 ℃。     

基于第一性原理的无铅无机钙钛矿Cs3Bi2X9(X=Cl、Br、I)光电性能表面效应研究

用基于第一性原理的密度泛函理论方法,对Cs₃Bi₂X₉(X=Cl、Br、I)的光电特性进行理论计算,并系统阐述这3种晶体的表面效应对光电性能的影响。结果表明,3种材料的光学特性由铋原子和卤素原子最外层p轨道上的价电子主导。在可见光区中,材料的吸收峰会随卤素原子序数的增加呈现红移,其中一维结构的Cs₃Bi₂Cl₉表面结构在光吸收能力上尤为特别且敏感;二维结构的Cs₃Bi₂Br₉光吸收能力会受厚度影响;零维结构的Cs₃Bi₂I₉非常稳定,且几乎不受表面特性和晶体厚度的影响。     

片状纳米结构CeO2晶体的制备及其吸附CO2性能

在室温下,将CeCl₃溶液与CO₂储存材料（CO₂SM）混合、搅拌0.5 h制备了片状碳酸铈前驱体（CCPs）,并在500℃下煅烧CCPs 4 h,制得平均尺寸为4.94 μm×0.92 μm,厚度为0.04~0.08 μm纳米结构片状CeO₂晶体。在此过程中,CO₂SM不但可以提供CO₃^2-,还能起到分散剂和结构导向剂的作用。反应过程中,系统地研究了CO₂SM用量、Ce³⁺浓度和搅拌时间3个因素对CCPs形态和大小的影响,得到最优制备条件：0.1 g CO₂SM和50 mL 0.03 mol·L^-1 Ce³⁺水溶液以1 000 r·min^-1转速在室温下搅拌0.5 h。煅烧CCPs后,所制备的片状CeO₂晶体在室温下CO₂吸附量可达0.554 mmol·g^-1。     

基于第一性原理的无铅无机钙钛矿Cs3Bi2X9(X=Cl、Br、I)光电性能表面效应研究

用基于第一性原理的密度泛函理论方法,对Cs₃Bi₂X₉（X=Cl、Br、I）的光电特性进行理论计算,并系统阐述这3种晶体的表面效应对光电性能的影响。结果表明,3种材料的光学特性由铋原子和卤素原子最外层p轨道上的价电子主导。在可见光区中,材料的吸收峰会随卤素原子序数的增加呈现红移,其中一维结构的Cs₃Bi₂Cl₉表面结构在光吸收能力上尤为特别且敏感;二维结构的Cs₃Bi₂Br₉光吸收能力会受厚度影响;零维结构的Cs₃Bi₂I₉非常稳定,且几乎不受表面特性和晶体厚度的影响。     

气相燃烧合成纳米复合粒子的形态与结构

在气相燃烧反应器中成功地合成了TiO₂-SiO₂、TiO₂-SnO₂复合粒子。TiO₂-SiO₂复合粒子中TiO₂以金红石型和锐钛型存在，SiO₂以无定型的形式存在。复合结构为SiO₂附着于TiO₂的外部，在Ti∶Si的进料比较大时SiO₂附着于TiO₂的表面，Ti∶Si比值减小到1∶4时，SiO₂包覆全部TiO₂表面。包覆层的厚度大约为6～7nm。TiO₂-SnO₂的复合粒子中同时存在着三种晶体结构SnO₂、金红石型和锐钛型的TiO₂。在复合粒子的表面，TiO₂和SnO₂两种组分分布均匀。通过改变进料方式可以调整复合粒子的结构。     

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。     

B2O3/TiO2-ZrO2的结构表征及其与酸性和催化性能间的关系

采用XRD、N₂吸附、 ¹¹B MAS NMR、NH₃-TPD和催化性能评价等方法研究了B₂O₃/TiO₂-ZrO₂催化剂的结构、酸性及催化环己酮肟气相Beckmann重排反应性能间的关系。结果表明,催化剂中的B₂O₃同时以三配位的BO₃和四配位的BO₄结构单元存在;     

g-C3N4/CaTi2O5复合材料制备及其光催化性能

利用类石墨氮化碳（g-C₃N₄）和亚稳相钙钛氧化物（CaTi₂O₅）固相法制备C₃N₄/CaTi₂O₅复合材料。利用X射线衍射（XRD）、金相显微镜、扫描电子显微镜（SEM）及附带能谱分析仪（EDS）和N₂吸附-脱附对样品的显微结构和比表面积进行检测分析,并用紫外-可见吸收光度计（UV-Vis）测试了样品的光吸收性能,研究C₃N₄与CaTi₂O₅物质的量之比（n_C3N4/nCaTi₂O₅）对C₃N₄/CaTi₂O₅复合样品的物相结构和微观形貌的影响,同时考察C₃N₄/CaTi₂O₅复合样品在可见光照射下光催化降解罗丹明染料效果。实验结果表明：相比纯C₃N₄和CaTi₂O₅样品,C₃N₄/CaTi₂O₅复合样品在可见光下具有较高的光催化性能,随着n_C3N4/nCaTi₂O₅增加,样品的光催化降解率随之增加而后降低,当n_C3N4/nCaTi₂O₅=1：1时,样品的光催化降解率达到最大值99.5%,并且循环重复利用5次后,样品的光催化剂降解率仍几乎保持不变。复合样品光催化性能提高主要归因于复合能级结构有效地抑制了电子和空穴复合所致。     

反应介质对溶剂热法合成CuS晶体的影响

以氯化铜、硫脲为反应物,通过溶剂热法合成了具有不同形貌的微纳米分级结构CuS晶体,研究了不同反应介质对材料的形貌、晶体结构以及反应产量等的影响。结果表明,以N,N-二甲基甲酰胺（DMF）为溶剂,可以得到微米级六角花状CuS晶体,以乙二醇或者水/DMF混合物为溶剂,得到的CuS晶体为微米球花状,CuS晶体的产量随着溶剂中水所占比例的增大,呈现先上升后下降的结果,当V_DMF：V_H2O=1：1时得到CuS的最大产量,为理论产量的64.5%。当V_DMF：V_H2O=2：1时得到的CuS晶体具有良好的光催化活性,能够在氙灯模拟的自然光照射2.5 h以内使罗丹明B污染物溶液的脱色率达到96.7%。     

反应介质对溶剂热法合成CuS晶体的影响

以氯化铜、硫脲为反应物,通过溶剂热法合成了具有不同形貌的微纳米分级结构CuS晶体,研究了不同反应介质对材料的形貌、晶体结构以及反应产量等的影响。结果表明,以N,N-二甲基甲酰胺(DMF)为溶剂,可以得到微米级六角花状CuS晶体;以乙二醇或者水/DMF混合物为溶剂,得到的CuS晶体为微米球花状。CuS晶体的产量随着溶剂中水所占比例的增大,呈现先上升后下降的结果,当V_(DMF)∶V_(H_2O)=1∶1时得到CuS的最大产量,为理论产量的64.5%。当V_(DMF)∶V_(H_2O)=2∶1时得到的CuS晶体具有良好的光催化活性,能够在氙灯模拟的自然光照射2.5 h以内使罗丹明B污染物溶液的脱色率达到96.7%。     

Insights into Proton Dynamics in a Photofunctional Salt-Cocrystal Continuum: Single-Crystal X-ray,Neutron Diffraction,and Hirshfeld Atom Refinement

X-ray diffraction, neutron diffraction, and theoretical calculations were used to investigate the relationship between the optical properties and degree of protonation in acid-base complexes. We prepared five acid-base complexes by using a pyridine-modified pyrrolopyrrole derivative and salicylic acid. Two of the prepared acid-base complexes were polymorphs of guest-free crystals with green emission; the other three were guest-inclusion crystals with yellow emission containing CH₂Cl₂, CH₂Br₂, or C₂H₄Cl₂. The presence or absence of guests caused the emission to change color, altering the hydrogen bond strength between the acid-base complexes. Accurate N⋅⋅⋅H distances between the pyridyl moiety and the carboxy group over the temperature range 123 to 273 K were 1.40 Å for the guest-free crystals and 1.25 Å for the guest-inclusion crystals. Our findings contribute to a better understanding of the complex relationship between photofunction and proton dynamics in acid-base complexes.     

Structure and Transport Properties of Zirconia-Based Solid Solution Crystals Co-Doped with Scandium and Cerium Oxides

The crystals of (ZrO₂)_1–x(Sc₂O₃) _x (СeO₂)_0.01 solid solutions (x = 0.08–0.10) were obtained by directional crystallization. The crystals of the grown composites were semitransparent, opalescent, and without cracks and had varying microstructure in the bulk. In the range of compositions under study, it was impossible to obtain optically homogeneous, fully transparent crystals. The crystals grown at a growth rate of 10 mm/h had a nonuniform distribution of ceria along the length of the ingot. The introduction of ceria in an amount of 1 mol % increased the conductivity of the crystals, but the increase in the specific electric conductivity depended on the Sc₂O₃ content and the phase composition of the crystals. The highest conductivity was inherent in the (ZrO₂)_0.89(Sc₂O₃)_0.10(CeO₂)_0.01 crystals.     

Distribution of dopant metals between PbTiO3 crystals and PbO-B2O3 flux

Single crystals of lead titanate PbTiO₃ doped with silicon, calcium, chromium, manganese, cobalt, nickel, copper, zinc, and cadmium were grown. The compositions and crystallographic parameters of the crystals were studied. The lowest distribution coefficients of dopants between PbTiO₃ crystals and flux were observed with Mn⁺² and Co⁺² and the highest, with Ca⁺². Doping with niobium leads to the formation of solid solutions with the pyrochlore structure A₂B₂O₇ and even higher distribution coefficient. A correlation was found between dopant concentrations and crystal cell parameters.     

An electron microscope study of tin dioxide and antimony-doped tin dioxide

Crystals of tin dioxide, SnO₂, have been grown pure or doped with a few percent of antimony using vapor growth methods in order to investigate the microstructures of reduced and oxidized SnO₂. They were examined by X-ray diffraction and by optical and electron microscopy. SnO₂ crystals were found to contain few faults, but the antimony-doped crystals were extensively twinned in some regions. Reduction of SnO₂ crystals to yield CS phases was unsuccessful. These results are discussed in terms of the known crystal chemistry of the oxides involved.     

Crystal growth of SnO2 and other MO2 (M = Ti,Zr, Hf) oxides by flux of B2O3?V2O5 system

Single crystals of SnO₂ and MO₂ (M = Ti, Zr, Hf) oxide were grown from flux of B₂O₃? V₂O₅ system. Mixtures of the flux and the starting powder of Zn₂SnO₄, TiO₂, ZrO₂, or HfO₂ were soaked at a temperature of 1030–1340°C for 10–72 hr and then were cooled down to 900°C at a rate of 5°C/hr. Grown crystals of SnO₂ were pale brown needles. An increase in V₂O₅ content of the flux (up to V₂O₅/B₂O₃ ratio equal to 2) or in the soaking temperature increases the crystal size. A largest crystal with the size of 15.0 × 0.4 × 0.4 mm was obtained in the case of V₂O₅/B₂O₃ = 2. Crystals of TiO₂ were black needles or platelets, and those of ZrO₂ and HfO₂ were yellowish, transparent needles or blocks. The maximum size of TiO₂, ZrO₂ or HfO₂ crystal was 12.0 × 0.1 × 0.1 mm, 4.0 × 0.3 × 0.3 mm or 11.0 × 0.6 × 0.6 mm, respectively. The long axis of the crystals was all C-axis and main faces on the crystals were of {100} and/or {110} families. All these crystals were found to include the impurities of boron and vanadium. The electrical resistivities of SnO₂ and TiO₂ crystals were measured to be 1.4 × 10⁶ and 5.6 × 10⁴ Ω · cm at 25°C, respectively.     

Recovery of host crystals from inclusion crystals of <Emphasis Type="Italic">p-tert-</Emphasis>butylcalix[4]arene and <Emphasis Type="Italic">p-tert</Emphasis>-butylthiacalix[4]arene by the treatment with a solvent and/or supercritical CO<Subscript>2</Subscript>

Upon stirring inclusion crystals of p-tert-butylthiacalix[4]arene (2) in solvents with heating, guest compounds were efficiently desorbed to yield guest-free crystals. More specifically, upon treatment with methanol, the exchange of guest compounds with methanol in the crystals, followed by the desorption of the methanol afforded metastable host crystals 2β, whereas, upon treatment with heptane, the dissolution of the inclusion crystals and simultaneous crystallization of compound 2 afforded stable host crystals 2α. Further, a host crystal of p-tert-butylcalix[4]arene (1) was recovered by the treatment of 2:1 (host/guest) inclusion crystals of compound 1 with supercritical carbon dioxide (scCO₂), and through the combination of the guest exchange of 1:1 inclusion crystals of compound 1 with hexane and scCO₂ treatment of the resulting 2:1 inclusion crystals 1₂·hexane. Although the recovered host crystal of compound 1 contained a small amount of CO₂, it could be reused for the inclusion of organic compounds.     

Growth and some properties of Sc2AlB6 crystal obtained from the solution in aluminum melt

Crystals of Sc₂AlB₆ were grown using scandium oxide and elemental boron as starting materials in a self-component aluminum solution under an argon atmosphere. The growth conditions for obtaining single crystals of relatively large size were investigated. Sc₂AlB₆ single crystals were obtained in the form of prisms extending in the b-axis direction. The largest Sc₂AlB₆ crystals prepared had maximum dimensions of about 0.4×0.4×4.2 mm³. The values of the Vickers microhardness and the electrical resistivity of Sc₂AlB₆ crystals are 12.7±0.8 GPa and 43±8 μΩ cm, respectively. The oxidation of Sc₂AlB₆ crystals starts at about 773°C, and the weight gain after TG determination is 12.9 mass% at 1200°C. The oxidation products of Sc₂AlB₆ crystals could not determined.     

Growth and characterization of n-WS2 and niobium-doped p-WS2 single crystals

Single crystals of n- and p-WS₂ were obtained by chemical vapor transport using chlorine and bromine as transporting agents. The best niobium-doped WS₂ crystals were obtained when the concentration of the charge (formulated (1 ? x)WS₂ · (x)NbS₂) was ? 37 mg charge/ml of tube, and x = 0.01 to 0.03. A thermodynamic analysis of the crystal growth process is consistent with the observed doping concentration and other properties of the crystals obtained by this process. The crystals grown are characterized by electrical transport and surface photovoltage measured capacitance techniques.