磷钨杂多阴离子P2W18O626-插层水滑石的制备

采用离子交换法,以镁铝硝酸根型水滑石(MgAl-NO3-LDHs)为前体,利用其独特的层状结构,进行了磷钨杂多酸阴离子P2W18O626-插层水滑石的制备研究,通过X射线衍射(XRD)、红外光谱(FT-IR)、热重-差热(TG-DTA)和紫外-可见光谱(UV-vis)等手段对样品结构进行了分析.结果表明,离子交换法制备得到了磷钨杂多酸阴离子P2W18O626-插层水滑石产物(MgAl-P2W18O626-LDHs),插层产物保持了原有的层状结构,且合适层板Mg2+/Al3+有利于形成晶体结构规整的插层产物.     

铁改性分子筛直接催化分解一氧化二氮

采用以离子交换法制备的Fe-ZSM-5、Fe-MCM-22和Fe-Beta分子筛催化剂,系统地考察了分子筛构型、酸性和酸中心分布对N2O直接催化分解的影响.采用N2吸附、红外光谱仪(FT-IR)、NH3程序升温脱附实验(NH3-TPD)、H2程序升温还原实验(H2-TPR)和原位漫反射红外光谱(in situ DRIFTS)等方法考察了铁离子负载量、Si与Al摩尔比和分子筛构型对N2O催化分解的影响.结果表明,价键补偿Fe3 离子是N2O分解的主要活性组分;分子筛活性随Si和Al摩尔比的减少和铁离子负载量的增加而增加;Fe-Beta分子筛的催化活性明显高于Fe-ZSM-5和Fe-MCM-22分子筛;分子筛酸性和酸中心分布影响铁离子的分布,从而导致不同构型分子筛催化分解N2O的活性具有明显差异.     

Zn/Al类水滑石及其插层材料的光催化性能

以氨水为共沉淀剂,采用低温共沉淀法合成了不同摩尔比的Zn/Al类水滑石,并通过离子交换法在层板间引入磷钨酸根离子,经焙烧后得到具有光催化性能的催化材料,研究插层前后类水滑石焙烧产物对甲基橙等染料的光催化降解性能。结果表明,CZn-Al-r催化剂具有优良的光催化降解有机染料的性能,通过调整催化剂前驱体中金属元素的比例,甲基橙和亚甲基蓝的降解率可在2 h内接近100%。而经磷钨酸插层后,IZnAl-2的光催化降解速率较CZnAl-2有所下降。     

AlH3P2W18O62?nH2O/MCM-41的制备、表征及催化合成阿斯匹林性能研究

通过浸渍法制备了MCM-41负载Dawson型磷钨酸铝催化剂(Al H3P2W18O62·n H2O/MCM-41),并用于催化合成阿司匹林,采用FTIR、XRD、SEM、EDS、NH3-TPD、Py IR、N2吸附-脱附及TG-DSC对其结构进行表征。探讨了磷钨酸铝负载量、催化剂用量、水杨酸与乙酸酐摩尔比、反应时间、反应温度及催化剂重复使用次数对阿司匹林收率的影响。结果表明,Al H3P2W18O62·n H2O均匀地负载在MCM-41载体上,负载后仍保持Dawson结构。与Al H3P2W18O62·n H2O相比,负载型催化剂(30%Al H3P2W18O62·n H2O/MCM-41)呈"蜂巢状",比表面积明显增大、热稳定性提高,同时具有Lewis酸中心和Brnsted酸中心,但酸强度降低。在优化反应条件下:即Al H3P2W18O62·n H2O负载量为30%(质量分数),w(30%Al H3P2W18O62·n H2O/MCM-41)=4.1%(基于反应物的质量),水杨酸与乙酸酐摩尔比1∶1.5,80℃反应30 min,产物收率为96.3%。催化剂可重复使用,第6次使用时产物收率达80.6%。30%Al H3P2W18O62·n H2O/MCM-41具有良好的催化活性和稳定性。     

环氧大豆油制备研究进展

叙述环氧大豆油制备的研究进展,包括羧酸催化环氧化和非羧酸催化环氧化。其中羧酸催化环氧化包括:羧酸催化环氧化,浓硫酸与羧酸联合催化环氧化、对甲苯磺酸与羧酸联合催化环氧化、酸性离子交换树脂与羧酸联合催化环氧化、固体强酸与羧酸联合催化环氧化、酶与羧酸联合催化环氧化,硫酸铝与羧酸联合催化环氧化;非羧酸催化环氧化包括:过渡金属配合物催化环氧化、磷钨杂多酸(盐)催化环氧化和相转移催化环氧化。     

采用混合离子交换树脂提取钨酸根

本项目利用分光光度计和电感耦合等离子体-质谱联用仪(ICP-MS)测定钨酸根浓度,采用201x7、201x W和201x4阴离子交换树脂吸附钨矿提取液中的钨酸根离子,探究阴离子树脂混合比例对钨酸根离子的离子交换量,以及提取液中共存的杂质离子锡酸根、钼酸根对钨酸根吸附量和选择性的影响。结果表明:201x4树脂对钨酸根离子的吸附量最大,但选择性差;杂质离子对树脂吸附量和选择性影响较大。动态实验表明杂质离子可使钨酸根解吸附曲线后移,钨酸根吸附量减少。     

蒙脱土负载钴(Ⅱ)-8羟基喹啉的制备及催化性能研究

采用离子交换和配位合成方法,通过配位键将配体引入金属蒙脱土层间,制备了Co(Ⅱ)-8Q/MMT复合催化材料,用IR和XRD分析了催化材料的结构,考察了催化剂催化氧化性能.实验结果表明,层间距增大0.332 nm,表明配体进入金属蒙脱土的片层间;在分子氧的氧化作用下,催化氧化苯乙烯的转化率达到42.3%.     

蒙脱土担载钴配合物催化剂制备及性能研究

制备了系列蒙脱土担载钴(Ⅱ)(Co(Ⅱ))配合物催化剂,并对其结构进行了X射线衍射和透射电镜等表征,初步研究了蒙脱土担载钴(Ⅱ)配合物催化剂对烯烃的催化氧化性能.结果表明:配体进入了蒙脱土的片层间与Co(Ⅱ)配位,形成蒙脱土担载的铜配合物复合催化材料;在催化剂催化H2O2氧化苯乙烯的反应中,对苯甲醛和环氧苯乙烷的选择性高达94.7%,转化率达到38.4%;在环己烯的氧化反应中,对环氧环己烷、环己醇、环己烯醇和环己烯酮的选择性共达到98.5%,转化率达到33.2%.     

非化学计量比镁铝尖晶石粉体的制备及性能

将异丙醇镁铝双金属醇盐滴加到含有5%(质量分数)EDTA分散剂的水解液中,制得镁铝氢氧化物无色透明溶胶,后经干燥、高温焙烧得到非化学计量比的铝镁尖晶石粉体。研究了Mg/Al摩尔比、焙烧温度、干燥工艺流程以及助溶剂的添加对粉体材料性能影响。结果表明:Mg/Al摩尔比在1.0:(2.5～4.0)范围内,1 200℃焙烧后对应粉体为纯相镁铝尖晶石结构,随铝含量增加,衍射峰向大角度方向偏移,且粉体颗粒粒径逐渐增大,Mg O·1.25Al_2O_3粉体红外透过率较高,可潜在应用于红外隐身等材料。     

不饱和脂肪酸甲酯的绿色催化环氧化研究

选用氧化钼/叔丁基过氧化氢/阴离子离子液体{MoO3/TBHP/[bmimPF6]}(I)和氧化钼/过氧化氢/阴离子离子液体{MoO3/H2O2/[bmimBF4]}(II)两种绿色催化体系,探索了反应时间、反应温度、氧化剂/不饱和双键摩尔比和催化剂/不饱和双键摩尔比4个因素对不饱和脂肪酸甲酯环氧化转化率的影响。研究表明,实验条件下催化体系Ⅰ比催化体系Ⅱ具有更高的活性,MoO3可重复使用3次。     

Synthesis, crystal structure and NMR of [Na(DB18C6)(CH3CN)]3[α-AsM12O40] (M = Mo/W)

Two super-molecular complexes [Na(DB18C6)(CH₃CN)]₃[α-AsM₁₂O₄₀] (M = Mo/W) were obtained by solvothermal reaction and characterized by IR,¹H ¹³C and gUMBC NMR, X-ray. The result reveals that the complex consists of a [α-AsM₁₂O₄₀]³⁻ (M = Mo/W) anion with α-Keggin structure, and three complex [Na (DB18C6)(CH₃CN)]⁺ cations in which every sodium ion is located in the cavity of dibenzo-18-crown-6 with 6 Na–O bonds and coordinated with one of the terminal O atom of [α-AsM₁₂O₄₀]³⁻ (M = Mo/W) and the N atom of CH₃CN from two sides of the distorted DB18C6 plane, respectively. The three terminal O atoms linked with sodium ion are from a single M₃O₁₃ (M = Mo/W) triplet of the α-Keggin metalatoarsenate anion, and M–O_b (M = Mo/W) bonds exhibit alternating single–double bond character.     

SHS Casting of (Mo,W)Si2, (Mo,Nb)Si2, and (Mo,Ti)Si2 silicides: effect of activating 3CaO2 + 2Al additives

(Mo,W)Si₂, (Mo,Nb)Si₂, and (Mo, Ti)Si₂ silicides and their solid solutions were prepared by the technique of SHS casting under 5 MPa of Ar pressure from thermit-like green mixtures containing the oxides of Mo, Nb, and Ti as well as activating 3CaO₂ + 2Al additives. The synthesized composites were characterized by XRD and EDS.     

Aluminum K-Edge Absorption (XANES) Studies of Noncrystalline Mullite Precursors

Noncrystalline aluminum silicate precursors MP1 and MP3 with different ratios of Al in tetrahedral (^[4]A1), pentahedral (^[5]A1), and octahedral (^[6]A1) position were prepared from aluminum sec-butylate and tetraethoxysilane (Al/Si ratio: 3/1) making use of a slow and rapid hydrolysis process, respectively. The MP2 precursor was synthesized from aluminum sec-butylate and silicon tetrachloride (Al/Si ratio: 4/1) by rapid hydrolysis. All aluminum silicate gels were heat-treated to temperatures just prior to crystallization to mullite and γ-Al₂O₃, respectively (MP1 and MP3: 800°C; MP2: 300°C). Al K near-edge absorption spectra (XANES) of the mullite precursors and of several suitable crystalline reference materials were measured using monochromatic synchrotron radiation. The reference XANES spectra yielded a linear correlation between the energy position of the first inflection point of the white lines and the frequency of sixfold-coordinated Al (^[6]A1) in the samples. A similar though less straightforward correlation seems to hold also for the white line intensities. From these findings, the actual ^[61]A1 frequencies for the mullite precursors under investigation were derived to be <10% (MP1), =30% (MP3), and =60% (MP2). The ^[6]A1 frequency distribution in the mullite precursors displays a trend similar to that determined by ²⁷A1 NMR spectroscopy.     

Structural characterization of iron-based bulk metallic glass alloys produced by centrifugal casting

In this study bulk metallic glass alloys in the Fe-Zr-B-M (M=Al, Co, Cu, Mo, Ni, W) systemwere produced by using a centrifugal casting method. The thickness ofthe samples that could be produced with an almost completely amorphousstructure was found to be as high as ～2 mm for alloy Fe60Co8Zr10Mo5W2B15. Alloying element additions or replacements have resulted in a considerable effect on glass-forming ability. Among others, Al and Cu were found to have the most deteriorative effects. The ternary alloy Fe70Zr10B20, from which bulk metallic glass alloys can be formed by cleverly implementing several alloying elements, was seen to have a different phase transformation behavior when compared to alloy Fe60Co8Zr10Mo5W2B15. For the latter alloy, the phase transformation process and microstructure evolution were found to be extremely sensitive to variation of the cooling rate.     

微波合成西佛碱络合物的电致发光性能

利用微波固相反应,合成了水杨醛-己二胺-锌Schiff碱络合物,通过时络舍物进行热分析,发现由己二胺合成的金属络合物具有较高的热稳定性,可用作电致发光材料。不加空穴转移层的器件发光亮度较低,而加入二胺作为空穴转移层材料器件的亮度可达1 390 cd/m2。     

过渡金属二取代钨钼三元杂多酸盐催化合成乙酸乙酯

合成了过渡金属二取代钨钼三元杂多酸盐：[TBA]4H3[PW7Mo3M2O38（H2O）2]（M=Fe^2＋、Co^2＋、Cu^2＋、Ni^2＋、Mn^2＋）,并利用红外光谱、紫外光谱对其结构进行表征,结果表明：它们都是具有Keggin结构的杂多化合物;并且利用它们催化合成乙酸乙酯,确定了最佳反应条件：酸醇物质的量比为1∶2;催化剂用量占总量的1%;最佳反应时间为5h;考察了它们的催化性能,其催化活性为：[TBA]4H3PW7Mo3Mn2O38（H2O）2〉[TBA]4H3PW7Mo3Ni2O38（H2O）2〉[TBA]4H3PW7Mo3Co2O38（H2O）2〉[TBA]4H3PW7Mo3Cu2O38（H2O）2〉[TBA]4H3PW7Mo3Fe2O38（H2O）2。     

Cu-Co-Al类水滑石的合成、表征及吸附NOx性能的研究

采用共沉淀法合成了铜钴铝不同摩尔投料比的碳酸根型水滑石(Cu/Co/Al摩尔比分别为111,121,131,141,151,161,171).用X-射线粉末衍射、红外光谱、热重-差热分析对它们进行了表征,测定了Cu-Co-Al类水滑石和活性炭对氮氧化物的吸附性能.结果表明,Cu-Co-Al的摩尔比在111～171时合成的复合金属氧化物都具有水滑石结构,Co的含量增加,水滑石层间高度略有增加.红外光谱分析结果表明羟基和碳酸根被插入到水滑石层间结构.热重-差热分析结果显示合成样品的分解均有两个过程,且含Co量增加,热稳定性减弱.二元的Co3Al-HTlc吸附NOx优于三元的CuCoAl-HTlcs和活性炭,CuCo3Al-HTlc对NOx吸附性能优于其它三元的CuCoAl-HTlcs.Co3Al-HTlc和CuCo3Al-HTlc吸附容量分别为1781mg·g-1、12861mg·g-1.     

Study of interface properties between Cu2ZnSnS4 thin films and metal substrates

In this study, the effects of various metal substrates on the interface properties of Cu₂ZnSnS₄ (CZTS)/metal structures were investigated. The crystal phases, morphologies, and element distributions at the interfaces between CZTS thin films and various metal substrates (Mo, W, Ti, and Al foils) were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and secondary ion mass spectroscopy. MoS₂ and WS₂ phases were formed at the CZTS/Mo and CZTS/W interfaces, respectively. No Ti-S and Al-S compounds were formed at the CZTS/Ti and CZTS/Al interfaces. The formation of these phases was dependent on the lowest reaction temperature between the metal foil and S vapor. The size of particles at the back surface of the CZTS thin film on the Ti substrate was larger than that on the other substrates, because the Ti element improved the crystallinity of CZTS. The presence of a thick WS₂ layer at the CZTS/W interface was attributed to the fact that the (211) plane of the W foil caused exposure of a greater number of W atoms in the sulfurization process because of the body-centered cubic crystal structure of W. The diffusion of Ti atoms into the CZTS thin film was due to the large average hop distance of defects in the CZTS thin film and the relatively low activation energy of Ti atoms. Current–voltage curves and energy band diagrams revealed that the ohmic contacts formed at the CZTS/Mo and CZTS/Ti interfaces were better than those formed at the CZTS/W interface and that a Schottky contact was formed at the CZTS/Al interface.     

Preparation of MoS2 and WS2 catalysts by in situ decomposition of ammonium thiosalts

The in situ decomposition of ammonium thiometallates during the hydrodesulfurization (HDS) of dibenzothiophene (DBT), to obtain molybdenum disulfide and tungsten disulfide catalysts, was investigated. It was found that very efficient catalysts for the HDS of DBT were obtained by in situ decomposition. Mechanical uniaxial pressing of the precursors (ammonium thiometallates) affected both textural and catalytic properties of the catalysts. Surface areas of molybdenum and tungsten disulfides increased as a function of uniaxial pressing, while catalytic activities went through a maximum. For MoS₂, the hydrogenation selectivity was much higher for in situ catalysts than for ex situ ones. For WS₂ catalysts, the hydrogenation selectivity was less sensitive to the condition of decomposition (ex situ/in situ). The surface S/M (M = Mo, W) atomic ratio from the Auger signal decreased as a function of uniaxial pressing, while the C/M ratio remained almost constant at 1.6. The best catalyst showed an experimental S/Mo ratio that is slightly higher than the stoichiometric value. The effect of in situ decomposition and mechanical deformation of thiometallate precursors is discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

锌/铝/镧三元类水滑石的合成

采用恒定pH值共沉淀法制得锌/铝/镧水滑石化合物(Zn/Al/La-CO3-LDHs),并探索了各种合成条件(如pH值、不同锌铝镧摩尔比、陈化温度等)对合成产物形成的影响,用X射线衍射(XRD)、红外(IR)和粒度分析等手段对合成样品进行分析和表征,并对产品的热稳定性能给出了重要的结论。结果表明,当控制溶液中n(M2+)/n(M3+)为3:1,n(La3+)/n(Al3+)为0.25,pH值为10,在85℃水浴反应,65℃陈化20h,能合成出晶相结构完整的水滑石化合物Zn/Al/La-CO3-LDHs,合成的产物可以大大改善聚氯乙烯的热稳定性。