长链烷胺及手性钛的螯合物Ti[(OC2H4)3N][OCH(CH3)2]在层状V2O5中的插层行为

用一种简便快速方法合成了一系列长链有机胺插层V₂O₅化合物. 用粉末X射线衍射(XRD)、红外光谱(FT-IR)、漫反射紫外-可见光谱(DR UV-VIS)等手段对插层产品的结构进行了表征. 除了正十六胺插层V₂O₅产品外, 其它长链烷胺插层V₂O₅产品的层间距d₀₀₁与长链烷胺碳数n之间具有良好的线性关系: d₀₀₁＝0.160n_C＋0.731 nm. 正十六胺与V₂O₅反应后生成两个插层相, 一个相的层间距d₀₀₁为4.01 nm, 另一相的d₀₀₁为3.20 nm. 此外, 研究了手性钛的螯合物Ti[(OC₂H₄)₃N][OCH(CH₃)₂] (记为TEAIP)在V₂O₅层间的插层行为, 得到相应的插层产品.     

内含式化合物X@Al12P12的结构与稳定性研究

采用B3LYP/6-31G*方法, 对内含式化合物X@Al₁₂P₁₂ (X＝Li^0/＋, Na^0/＋, K^0/＋, Be^0/2＋, Mg^0/2＋, Ca^0/2＋, H和He)的不同对称性构型进行计算, 讨论其最稳定构型的几何参数、布居分析、偶极矩、电离势、包含能、频率、HOMO-LUMO能隙和自旋密度．发现X@Al₁₂P₁₂化合物中, 客体X＝Na^0/＋, K^0/＋, Mg和He几乎处在笼的中心, Be和Ca^0/2＋处在中心附近0.033 nm的半径内, Li^0/＋, Be^2＋, Mg^2＋和H很大程度上偏离笼的中心位置. 大部分金属内含式化合物的C₃对称性构型稳定．Li^0/＋, Be^0/2＋, Mg^2＋, Ca^2＋和H与其它离子相比更易嵌入笼内形成稳定的内含式化合物.     

长链烷胺及手性钛的螯合物Ti[(OC2H4)3N][OCH(CH3)2]在层状V2O5中的插层行为

用一种简便快速方法合成了一系列长链有机胺插层V₂O₅化合物. 用粉末X射线衍射(XRD)、红外光谱(FT-IR)、漫反射紫外-可见光谱(DR UV-VIS)等手段对插层产品的结构进行了表征. 除了正十六胺插层V₂O₅产品外, 其它长链烷胺插层V₂O₅产品的层间距d₀₀₁与长链烷胺碳数n之间具有良好的线性关系: d₀₀₁＝0.160n_C＋0.731 nm. 正十六胺与V₂O₅反应后生成两个插层相, 一个相的层间距d₀₀₁为4.01 nm, 另一相的d₀₀₁为3.20 nm. 此外, 研究了手性钛的螯合物Ti[(OC₂H₄)₃N][OCH(CH₃)₂] (记为TEAIP)在V₂O₅层间的插层行为, 得到相应的插层产品.     

NiAl类水滑石/皂石层状复合材料的制备及结构表征

以NiAl类水滑石和八面体片阳离子为Zn²⁺的皂石为前体，利用两前体层板带电荷的相反性和层间域离子的可交换性，在室温、常压的温和实验条件下，将带正电荷的类水滑石层板引入到带负电荷的皂石层间，首次合成出了一种新型层状复合材料——NiAl类水滑石/皂石层状复合材料。XRD、DTA、IR和²⁷Al MAS NMR的测试结果表明，类水滑石八面体层板已顺利插层到皂石片层之间，复合材料在c轴方向是单个皂石层板与单个类水滑石层板的交叉堆叠。DTA分析结果还表明，该层状复合材料具有高热稳定性，结构破坏温度高达837 ℃。     

Ag/ZrO2催化剂上的1,2-丙二醇选择性气相氧化反应

采用浸渍法制备了一系列Ag/ZrO₂催化剂, 考察了Ag/ZrO₂催化剂对1,2-丙二醇选择性氧化合成丙酮醛反应的催化性能. 实验结果表明: 在原料气配比为V(N₂)∶V(O₂)＝300∶19, n(O₂)/n(alcohol)＝1.2, 反应物液时空速为3.2 g/(g•h), 反应温度为673 K时, 1,2-丙二醇选择性氧化合成丙酮醛反应的转化率为95.7%, 选择性为55.3%, 高于传统电解银催化剂. UV-Vis DRS和XPS的研究结果表明: 在Ag/ZrO₂催化剂上存在大量的Ag^＋和Ag_n^δ＋有利于促进催化活性的提高.     

五氧化二钒插层纳米复合材料的组装与电化学性能

五氧化二钒具有二维空间层状结构,层间伸缩性好,具有纳米尺寸,且有可做成无定形、高比表面积的溶胶.凝胶、干凝胶、气凝胶和类气凝胶等多种形态的优点.目前以其为主体的插层纳米复合材料研究十分活跃,本文综述了近年来合成的五氧化二钒插层化合物的组装及其电化学性能研究的进展.     

锂-, 钠-, 钾水化蒙脱石层间结构的分子动力学模拟

运用分子动力学(molecular dynamics, MD)方法分别研究了含有32, 64和96个水分子的Li-, Na-, K-蒙脱石层间阳离子与水分子的位置和结构. 计算结果表明蒙脱石层间阳离子位置与四面体和八面体电荷位置及离子的大小有关. 一层水合物中可以观察到三种阳离子都能和四面体电荷与八面体电荷位置分别形成内、外配位作用. 二层水合物中, 仍然可以观察到Li^＋和Na^＋与电荷位置的配位作用, 但是已经开始向层中其他方向扩散, 而K^＋仍然在粘土的表面附近. 三层水合物中, Li^＋, Na^＋开始从电荷位置和表面分离, K^＋也开始向层间其他方向扩散. 水分子在所有三种水合物中都分散于层间各个方向. 径向分布函数的分析结果表明层间三种阳离子组织水分子的能力不同, 水化作用随着阳离子半径的增大而减弱; 此外层中水分子的聚合程度随着水分子的增加而加强, 水分子的结构也不同于模拟的液体水分子的结构; 说明蒙脱石层间阳离子的溶剂化作用对水分子的组织起着重要的作用.     

以[M(DETA)2)]n+(M=Cu2+, Ni2+, Co3+)为客体的MnPS3夹层化合物的合成、结构表征与磁性研究

将过渡金属配合物阳离子([M(DETA)₂]ⁿ⁺(M=Cu²⁺,Ni²⁺,Co³⁺;DETA=Diethylenetriamine,二乙烯三胺)作为客体插入层状MnPS₃层间得到了相应的3个夹层化合物。通过X-射线粉末衍射、元素分析和红外光谱对夹层化合物的结构进行了表征。结果表明,与主体MnPS₃ 0.65 nm的层间距相比较,夹层化合物(Mn_0.88PS₃[Cu(DETA)₂]_0.12)的层间距扩大了0.32 nm,由此推测客体[Cu(DETA)₂]²⁺在层间以平面四方的配位形式存在,而另2个夹层化合物(Mn_0.79PS₃[Ni(DETA)₂]_0.21和Mn_0.74PS₃[Co(DETA)₂]_0.17)的层间距扩大了0.48 nm,说明客体[(M(DETA)₂]ⁿ⁺,M=Co³⁺,Ni²⁺) 在主体层间以八面体配位形式存在。磁性测试结果表明过渡金属离子[(M(DETA)₂]ⁿ⁺(M=Cu²⁺,Co³⁺)的插入能引起主体MnPS₃的磁性在35~40 K发生由顺磁向亚铁磁性的转变并表现自发磁化,而客体[Ni(DETA)₂]²⁺却使夹层化合物的反铁磁相互作用增强,抑制了自发磁化的发生。     

一种新型无机—有机杂化多钒酸化合物[Ni(bpp)2]2(V4O12)[bpp＝ 1,3－联(4－吡啶基)丙烷]的合成与表征

本文以NiCl₂·6H₂O、1,3－联(4－吡啶基)丙烷（bpp）、NH₄VO₃、乙醇、水为原料，采用水热法成功的合成了一种无机－有机杂化多钒酸化合物[Ni(bpp)₂]₂(V₄O₁₂)。该化合物包含彼此互相垂直的二维共价层所形成的二重互穿网络_∞2{Ni(bpp)₂}_n²ⁿ⁺和连接_∞2{Ni(bpp)₂}_n²ⁿ⁺的环形四核簇{V₄O₁₂}^4-。该化合物具有三维网状结构，属于四方晶系，空间群为I4₁/a，晶胞参数是：a = 2.14705 nm, c =1.29293 nm。对[Ni(bpp)₂]₂(V₄O₁₂)的漫反射光谱研究表明，此化合物的光学能隙值约为2.70eV，具有半导体性质。     

N-烷基吡啶阳离子及其与若干阴离子形成的离子对结构的理论研究

采用密度泛函理论方法, 在B3LYP/6-31＋G(d) 水平上研究了吡啶、N-烷基吡啶阳离子及其与若干阴离子(F^－, Cl^－, Br^－, , )形成的离子对的稳定构型. 计算结果表明: N-烷基吡啶阳离子的吡啶环与中性吡啶分子类似, 具有芳香性, 烷基对吡啶环结构影响不大; 离子对中阴离子易出现在吡啶环上方以及C(5)—H 或C(2)—H 和 N-甲基附近; 阴、阳离子之间通常存在多重氢键, 并且均有部分电荷转移; 离子对的相互作用能随着N-烷基的增长而减小.     

Preparation and characterization of novel alkylviologens-intercalated vanadyl-vanadate (RV)V3O8

Various n-alkylviologens-intercalated vanadyl-vanadate (RV)V₃O₈ were synthesized with the combination of redox and ions-exchange methods. The derivative compounds were characterized by X-ray diffraction (XRD), FT infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). The XRD results indicate that the interlayer spacing increases with the alkyl chain length of the alkylviologen cations. The FTIR data shows that alkylviologens were inserted into the interlayers of V₃O₈²⁻. XPS data reveals that the vanadium ions in the intercalation compounds are mostly in a pentavalent V⁵⁺ state with some partially reduced to the V⁴⁺ state. The intercalation compounds have the strong absorption character in the ultraviolet and visible light region. Magnetic susceptibility indicates that the (ethylviologen) V₃O₈ (EV3) is antiferromagnetic and possesses an ordered magnetic structure below 15 K. Above 15 K, EV3 exhibits paramagnetic behavior and a disordered magnetic structure.     

Effect of Bi promoter on the performances of selective oxidation of isobutane to methacrolein over MoVO/AlPO4 catalysts

The effects of Bi on the catalytic performance of selective oxidation of isobutane to methacrolein over MoVO/AlPO4 catalyst were investigated by XRD, FT-Raman, XPS, UV-vis DRS techniques. The results show that the addition of Bi component into the MoVO/AlPO4 catalyst obviously improves the catalytic performance, and the selectivity to methacrolein can increase from 14.2% to 45.1% with the increase of Bi/V molar ratio from 0 to 1. Combining the characterization results with the reaction evaluation, it is concluded that the catalytic activities of the MoV0.3Bix/AlPO4 catalysts are related to the crystalline phase composition and the dispersion of molybdenum and vanadium oxides species in general, and also to the V5+/V4+ molar ratio on the surface in particular.     

Synthesis and Characterization of Diamine Intercalation Compounds of SnS2 Single Crystals

Single crystals of SnS₂ were intercalated with ethylenediamine (en) and propylenediamine (pn) by direct reaction. The resulting novel compounds were examined by different techniques including XRD, XPS, a.c. impedance, TG, and TPD measurements. The observed lattice expansion for both compounds, ca. 3.9 Å, is consistent with the location of the amine molecules at van der Waals gaps, with monolayers in the alkyl chain parallel to the sulfur layers. XPS data reveal that these complexes easily absorb moisture that binds strongly to sulfur to give hydrogen sulfide traces that were detected upon thermal deintercalation above 473 K. However, the charge transferred from the guest to the host is too small to be detected by this photoelectron technique. The en intercalate preserves the semiconductor behavior of the pristine compound, SnS₂, but with two significant differences, viz. lower conductivity at low temperatures and an increased activation energy. These differences are ascribed to increased incoherent scattering of electrons resulting from the guest atoms acting as impurities and also to the lattice defects formed upon intercalation.     

Intercalation chemistry of layered vanadyl phosphate: a review

The intercalation chemistry of layered α_I modification of vanadyl phosphate and vanadyl phosphate dihydrate is reviewed. The focus is on neutral molecular guests and on metal cations used as guest species. The basic condition for the ability of the neutral molecules to be intercalated into vanadyl phosphate is a presence of an electron donor atom in them. The most commonly used guest compounds are those containing oxygen, nitrogen or sulfur as electron donor atoms. Regarding the molecules containing oxygen, various compounds were used as molecular guests starting from water to alcohols, ethers, aldehydes, ketones, carboxylic acids, lactones, and esters. An arrangement of the guest molecules in the interlayer space is discussed in connection with the data obtained by powder X-ray diffraction, thermogravimetry, IR and Raman spectroscopies, and solid-state NMR. In some cases, the local structure was suggested on the basis of quantum chemical calculations. Besides of those O-donor guests, also N-donor guests such as amines, nitriles and nitrogenous heterocycles and S-donor guests such as tetrathiafulvalene were intercalated into VOPO₄. Also intercalates of complexes like ferrocene were prepared. Intercalation of cations is accompanied by a reduction of vanadium(V) to vanadium(IV). In this kind of intercalation reactions, an iodide of the intercalated cation is often used as it serves both as a mild reduction agent and as a source of the intercalated species. Intercalates of alkali metals, hydronium and ammonium were prepared and characterized. In the case of lithium and sodium intercalates, a staging phenomenon was observed. These redox intercalated vanadyl phosphates undergo ion exchange reactions which are discussed from the point of the nature of cations involved in the exchange. Vanadyl phosphates in which a part of vanadium atom is replaced by other metals are also briefly reviewed.     

草酸还原法制备VO_2(英文)

利用草酸还原五氧化二钒的方法制备系列低价钒氧化合物。将混匀的原料置于高纯N2洗气后的石英管中,600℃反应2h,nV2O5:nH2C2O4在1:0.5至1:2.5范围变化时,可以分别得到单一物相的V6O13,VO2和V2O3粉体。通过XRD,XPS,EPR,电阻测量及磁性测试等手段对VO2样品进行了表征,结果显示VO2样品在65℃附近发生从半导体到金属的相变,并且其电学和磁学性质变化与文献报道基本一致。     

Hybrid materials based on vanadium pentoxide intercalation complexes

Neutral macrocyclic compounds (crown ethers and cryptands) and charged molecular species (alkylammonium iodides) were intercalated into vanadium oxide xerogel (V₂O₅ · nH₂O) to study their influence on the electrical behaviour of this inorganic 2D host lattice. Treatment with alkyl or arylammonium iodide solutions produced the intercalation of organic cations accompanied by the reduction of a fraction of V (V) to V (IV). Characterisation by different techniques allowed the postulation of the interlayer arrangement of the guest species. The study of electrical behaviour at different temperatures indicated that the properties of the hybrid materials can be mainly related to the nature of guest species, the degree of host lattice reduction, the interlayer water content, and the␣presence of metal ions deliberately introduced in the system. Received: 23 January 2001 Accepted: 5 April 2001     

共沉淀法掺杂SiO_2对V_2O_5-WO_3/TiO_2催化剂SCR性能的影响

通过共沉淀法将SiO_2组分掺入到V2O5-WO3/SiO_2-TiO_2催化剂TiO_2载体中,并通过多种物理化学手段,考察了不同SiO_2掺杂量对催化剂结构、表面性质与SCR性能的影响.结果表明,SiO_2掺入到TiO_2中,Si与Ti形成Si—O—Ti键,使催化剂比表面积增加.Si—O—Ti键的生成以及Si Ox物种上的-OH基团使催化剂表面Br?nsted酸增加,但新增的Br?nsted酸对SCR反应不利,并且SiO_2的掺杂也使得V~(5+)含量降低,Si—O—V键合作用使分散的VOx物种更难还原.Si组分以共沉淀法掺入到V_2O_5-WO_3/TiO_2催化剂会造成脱硝活性的显著下降.     

Structural aspects of the metal-insulator transitions in V0.985Al0.015O2

The crystal structure of V_0.985Al_0.015O₂ has been refined from single-crystal X-ray data at four temperatures. At 373°K it has the tetragonal rutile structure. At 323°K, which is below the first metal-insulator transition, it has the monoclinic M₂ structure, where half of the vanadium atoms are paired with alternating short (2.540 Å) and long (3.261 Å) V-V separations. The other half of the vanadium atoms form equally spaced (2.935 Å) zigzag V chains. At 298°K, which is below the second electric and magnetic transition, V_0.985Al_0.015O₂ has the triclinic T structure where both vanadium chains contain V-V bonds, V(1)-V(1) = 2.547 Å and V(2)-V(2) = 2.819 Å. At 173°K the pairing of the V(1) chain remains constant: V(1)-V(1) = 2.545 Å, whereas that of the V(2) chain decreases: V(2)-V(2) = 2.747 Å. From the variation of the lattice parameters as a function of temperature it seems that these two short V-V distances will not become equal at lower temperatures. The effective charges as calculated from the bond strengths at 298 and 173°K show that a cation disproportionation has taken place between these two temperatures. About 20% of the V⁴⁺ cations of the V(1) chains have become V³⁺ and correspondingly 20% of the V⁴⁺ cations of the V(2) chains have become V⁵⁺. This disproportionation process would explain the difference between the two short V-V distances. Also it would explain why the T → M₁ transition does not take at lower temperatures.     

Cu、Ag、Au掺杂BiVO_4可见光催化剂的制备及性能研究

水热法制备了币族金属(Cu、Ag和Au)掺杂的BiVO4可见光催化剂,借助X-射线衍射(XRD)、X-射线光电子能谱(XPS)、紫外-可见漫反射光谱(DRS)和扫描电子显微镜(SEM)对其进行表征.XRD分析显示所有催化剂都呈现单斜结构.XPS结果显示掺杂元素均以其稳定氧化态形式存在与催化剂表面.DRS谱中掺杂样品的吸收边界比纯BiVO4都有不同程度的红移.以甲基橙的可见光催化降解反应为探针,研究了催化剂的可见光催化性能.结果表明,经币族金属掺杂改性的催化剂催化能力比纯BiVO4有所提高.对其掺杂增强催化能力的可能原因进行了分析讨论.