Y沸石的高温合成

采用甲基三乙氧基硅烷(MTS)为添加剂, 在高温(140 °C)条件下水热合成出具有六方片状形貌的Y型沸石. 相比于100 °C左右合成的Y型沸石, 高温合成的Y沸石具有更高的硅铝比值、更大的晶体宽厚比值以及对有机挥发物具有优异的吸附性能. 通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、²⁹Si固体核磁共振(NMR)、傅里叶变换红外(FTIR)光谱、碳氢氮元素分析(CHN)、水接触角等表征, 证明了所合成的新型Y沸石具有甲基基团, 它们的存在增强了疏水性能, 提高了对有机挥发物的吸附能力.     

Effect of Sodium Concentration on the Synthesis of Faujasite by Two-step Synthesis Procedure

The relationship between the concentration of sodium cations and the properties of faujasite(FAU) zeolite was investigated using a two-step synthesis procedure including (1) formation of amorphous aluminosilicate precursors and separation of amorphous nanoparticles, and (2) transformation of these amorphous particles into zeolite crystals by treatment with alkali solutions(NaOH). Three representative samples including two nano-sized zeolites and one micron-sized zeolite were prepared using different concentrations of sodium hydroxide. The crystallization process of these zeolites was studied in detail by Fourier transform infrared(FTIR) spectrometry, nuclear magnetic resonance spectroscopy(NMR), X-ray diffraction(XRD), scanning electron microscopy (SEM), transmission electron microscopy(TEM), and N₂ adsorption. The results indicated that minor changes in the concertation of inorganic cations can significantly shorten the induction period and crystallization time and thus affect the morphology, size and chemical composition of the zeolite crystals.     

The preparation and analysis of zeolite ZSM-5 membranes on porous alumina supports

Zeolite ZSM-5 particles formed in the synthesis solution assume a negative charge due to electrical double layer effects. Therefore, we investigated the use of electrophoretic techniques in addition to the hydrothermal synthesis method to attract the zeolite particles to the substrate surface before they precipitate out of the solution. This electrophoretic driving force produces a thin, continuous zeolite ZSM-5 membrane on the porous substrate. This research was conducted in order to produce zeolite membranes on a tubular support that could effect continuous gas phase separations. The thickness of membranes can be controlled by varying the precursor concentration, applied potential, and synthesis time. The selectivity of n-butane over iso-butane is observed on every membrane. The membranes were characterized by using scanning electron microscopy (SEM), X-ray diffractometry (XRD), and energy dispersive X-ray spectrometry (EDX).     

以二甲基二乙基氢氧化铵为模板剂UZM-8沸石的合成与表征

以二甲基二乙基氢氧化铵(DEDMAOH)作为模板剂, 通过水热合成方法制备了新型层状沸石材料UZM-8, 并考查了DEDMAOH模板剂用量及投料硅铝比对UZM-8沸石结构的影响. 采用X衍射(XRD)、扫描电子显微镜(SEM)、傅立叶变换红外(FT-IR)、热重分析(TG, DTG)等方法对所得系列UZM-8沸石进行了表征. 该层状沸石具有与MCM-56相似的MWW结构, 但层间距及其堆积方式等有所不同. 当DEDMAOH/SiO2＜0.3时, 无法有效合成出UZM-8沸石. 随硅铝比的提高, UZM-8在2θ角6.6°和7.1°处的两个衍射峰转变为一个峰, 层间沿c轴方向收缩.     

Preparation of thin layer materials with macroporous microstructure for SOFC applications

A facile and versatile method using polymethyl methacrylate (PMMA) microspheres as pore formers has been developed to prepare thin layer oxide materials with controlled macroporous microstructure. Several mixed oxides with fluorite and perovskite-type structures, i.e. doped zirconia, ceria, ferrites, manganites, and NiO-YSZ composites have been prepared and characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption and mercury porosimetry. The synthesised materials are nanocrystalline and present a homogeneous pore distribution and relatively high specific surface area, which makes them interesting for SOFC and catalysis applications in the intermediate temperature range.     

具有多级孔道结构、高水热稳定性的含氧化镁Silicalite-1分子筛的合成

通过焙烧将分散在多孔氧化硅母体中的硝酸镁转化成高分散的MgO物种, 然后使用四丙基氢氧化铵(TPAOH)作为结构导向剂, 将含MgO 的母体通过水热晶化合成MgO/silicalite-1 分子筛复合物. X 射线衍射(XRD)、能量X射线光谱(EDX)和透射电镜(TEM)的结果表明MgO物种被均匀地分散在silicalite-1 分子筛晶体中. 将酸处理脱除氧化镁前后的样品在100%水蒸汽800℃ 条件下老化, 结果表明MgO 的引入有效地提高了分子筛的水热稳定性. 此外, 酸洗脱除MgO/silicalite-1分子筛中的MgO提高了分子筛结晶度, 同时引入了一定的介孔. N₂物理吸附-脱附数据证明了酸洗后分子筛中介孔的存在. 水热稳定性的提高和介孔的引入对于在高温下保持催化剂的孔道结构, 提高催化剂的抗积碳能力, 降低催化剂的失活速率以及延长催化剂的使用寿命起着非常重要的作用.     

Controllable synthesis of composites of ZSM-5 and KIT-1 using an ionic liquid as template

ZSM-5/KIT-1 composites were synthesized using an ionic liquid as a template. The structures and morphologies of as-obtained products were characterized using an infrared spectroscopy, X-ray diffractometer, N₂ adsorption/desorption, scanning electron microscopy and transmission electron microscopy. The resultant zeolites show a fully crystalline microporous MFI zeolite framework and a three-dimensional network of short worm-like channels. Mesopores and microspores of 4.2 and 0.8 nm in diameter coexist in the zeolite composites. Moreover, the ratio of ZSM-5 and KIT-1 could be simply adjusted by controlling the pre-crystalline time. We believe that the strategy for fabricating ZSM-5/KIT-1 through a simple method could potentially promote the large-scale production of zeolite composites.     

A new strategy for the controlled deposition of gold nanoparticle aggregates on two-dimensional polystyrene arrays and its application in glucose oxidase immobilization

Zeolite 4A (LTA) has been successfully synthesized by a hydrothermal method, where kaolin was used as silica and alumina source. The synthesized zeolite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), laser granulometry, and FTIR spectroscopy. XRD data from the Rietveld refinement method confirmed only one crystallographic phase. Zeolite A morphology was observed by SEM analysis, and it showed well-defined crystals with slightly different sizes but with the same cubic shape. Particle size distribution of the crystals was confirmed by laser granulometry, whereas FTIR spectroscopy revealed significant structural differences between the starting material and the final zeolite product used as water softener.     

Preparation and properties of graphene oxide nanosheets/cyanate ester resin composites

Graphene oxide nanosheets (GONSs)/cyanate ester (CE) resin composites were prepared via a solution intercalation method. The structures of the GONSs and the composites were studied using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The mechanical and tribological properties of the composites were investigated. In addition, the thermal behavior of the composites was characterized by thermogravimetric analysis (TGA). Results show that the GONSs/CE resin composites were successfully prepared. The addition of GONSs is beneficial to improve the mechanical and tribological properties of the composites. Moreover, the composites exhibit better thermal stability in comparison with the CE resin matrix.     

Microwave absorption studies of polyaniline nanocomposites encapsulating gold nanoparticles on the surface of reduced graphene oxide in the presence of 2-naphthalene sulfonic acid

Polyaniline nanocomposites containing gold nanoparticles (GNPs) attached to the surface of reduced graphene oxide (RGO) were chemically prepared using β-naphthalene sulfonic acid as a dopant. The synthesized composites were characterized using Fourier transform infrared spectroscopy and UV-vis spectroscopy, and their surface morphology and amended crystallinity were determined by scanning electron microscopy and X-ray diffraction, respectively. Further the elemental analysis was also performed to identify the synthesized polymer composites. Complex impedance measurements were performed on the composite samples in the form of films. Sheets prepared by conventional techniques were used to study the microwave absorption properties in the microwave range of 2–12?GHz, and the effects of sample thickness on the microwave absorption were investigated. Experimental results show that the electrical conductivity of the composites increases with increasing concentrations of added GNP-RGO without a percolation threshold.     

TEM investigation of nanophase aluminum powder.

Nanophase aluminum powder was characterized in a field-emission-gun transmission electron microscope (TEM). Different techniques were used to investigate the structure of the particles, including conventional bright-field and dark-field imaging, scanning transmission electron microscopy (STEM), high-resolution lattice imaging, diffraction studies, energy dispersive X-ray spectroscopy (EDS) analysis and mapping, and electron energy loss spectroscopy (EELS) analysis and mapping. It has been established that the particle cores consist of aluminum single crystals that sometimes contain crystal lattice defects. The core is covered by a passivating layer of aluminum oxide a few nanometers thick. The alumina is mostly amorphous, but evidences of partial crystallinity of the oxide were also found. The thickness of this layer was measured using different techniques, and the results are in good agreement with each other. The particles are agglomerated in two distinct ways. Some particles were apparently bonded together during processing before oxidation. These mostly form dumbbells covered by a joint oxide layer. Also, oxidized particles are loosely assembled into relatively large clusters.     

Pulsed laser ablated zeolite nanoparticles: A novel nano-catalyst for the synthesis of 1,8-dioxo-octahydroxanthene and N-aryl-1,8-dioxodecahydroacridine with molecular docking validation

There is an increasing interest in the synthesis of metal nanoparticles (NPs) from bulk metals using pulsed laser ablation in liquids (PLAL), as it offers an easy and simple synthesis route. In this work, zeolite NPs (molecular sieve 4A) were successfully synthesized by the PLAL technique, and characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. Data obtained confirm the formation of the crystalline phase of zeolite. The synthesized catalyst (zeolite molecular sieve 4A) was used as an efficient and facile promotor for the synthesis of xanthene and acridine derivatives. Molecular docking of the synthesized compounds was validated using quinone reductase 2 (NQO2) and acridine orange as the ligand, with the synthesized molecules showing good drug–ligand interaction on the active site of NQO2, compared with that of acridine orange.     

In2O3/CdO复合材料的制备及气敏特性

采用水热合成方法制备了花状In2O3纳米材料.利用X射线衍射(XRD)、扫描电镜(SEM)、能量色散X射线光谱(EDX)及透射电镜(TEM)对材料的结晶学特性及微结构进行了表征.制备的In2O3材料呈现花状,是由粒径约20nm的椭球状小颗粒构成的分级结构材料.将制备的In2O3与纳米CdO以摩尔比1:1混合后,发现制成的In2O3/CdO复合材料经热处理后呈现葡萄状多孔结构.测试In2O3/CdO复合材料制作的气敏元件处于最佳工作温度(410°C)时,对0.05×10-6(体积分数,φ)的甲醛气体表现出较高的灵敏度.对比测试发现,In2O3/CdO复合材料制作的气敏元件对不同浓度甲醛的灵敏度明显优于纯花状In2O3纳米材料.同时In2O3/CdO复合材料制作的气敏元件在乙醇、甲苯、丙酮、甲醇以及氨气等干扰气体中具有对甲醛良好的选择性.讨论了In2O3/CdO复合材料气敏元件的敏感机理.     

Microwave and UV Assisted Methods for Obtaining Novel Composites Based on Fe<Subscript>2</Subscript>O<Subscript>3</Subscript> with Embedded Gold Nanoparticles

Metallic nanoparticles embedded into the structure of metal oxides may play a role of catalytic substances. Such composites are mostly applied in oxidation reactions. The paper presents two one-step-methods for obtaining nanocomposites of gold embedded in the structure of iron oxide matrices (nanoAu/Fe₂O₃). Gold nanoparticles were formed in situ in the process of iron hydroxide dehydration. Thanks to the use of tannic acid it was possible to effectively reduce gold ions and stabilize the forming metal nanoparticles. The composites were prepared in the fields of microwave, ultraviolet radiation. The physicochemical properties of products were determined by scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray analysis and high-resolution transmission electron microscopy technique with EDS and elemental mapping mode. Also, the catalytic activity of the nanocomposites obtained was evaluated based on the process of methyl orange degradation. It was observed that products obtained according to the microwave radiation method are characterized by improved applying properties.     

Synthesis of mesoporous zeolite single crystals with cheap porogens

Mesoporous zeolite (silicalite-1, ZSM-5, TS-1) single crystals have been successfully synthesized by adding soluble starch or sodium carboxymethyl cellulose (CMC) to a conventional zeolite synthesis system. The obtained samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen sorption analysis, ²⁷Al magic angle spinning nuclear magnetic resonance (²⁷Al MAS NMR), temperature-programmed desorption of ammonia (NH₃-TPD) and ultraviolet-visible spectroscopy (UV-vis). The SEM images clearly show that all zeolite crystals possess the similar morphology with particle size of about 300 nm, the TEM images reveal that irregular intracrystal pores are randomly distributed in the whole crystal. ²⁷Al MAS NMR spectra indicate that nearly all of the Al atoms are in tetrahedral co-ordination in ZSM-5, UV-vis spectra confirm that nearly all of titanium atoms are incorporated into the framework of TS-1. The catalytic activity of meso-ZSM-5 in acetalization of cyclohexanone and meso-TS-1 in hydroxylation of phenol was also studied. The synthesis method reported in this paper is cost-effective and environmental friendly, can be easily expended to prepare other hierarchical structured zeolites.     

微波辅助合成石墨烯/氧化镍复合材料及其表征

本文通过微波辅助的方法,快速而有效地在热膨胀石墨烯(RG)的缺陷上原位合成氧化镍纳米颗粒,形成石墨烯/氧化镍复合材料(RG/NiO)。利用X-射线衍射(XRD),拉曼光谱(Raman),傅里叶变换红外(FTIR),扫描电镜(SEM),透射电镜(TEM),热重-差热(TGA-DSC)对所制备样品的结构、形貌和NiO在复合材料中的含量进行表征。结果表明,热膨胀石墨烯层数约7~8层,层间距约为0.35 nm,缺陷多,在水热和微波处理后抗氧化性明显变差。复合材料中氧化镍颗粒平均粒径为25 nm,均匀而密集地分散在石墨烯平面上,同时在复合材料中的含量为19.8%。     

One-step Growth of Hierarchical Nanotreelike TiO_2 on ITO without Template and Its Application in Gas Sensor

In this work, a distinctive hierarchical tree-like rutile TiO_2 architecture growing directly on the conductive surface of indium tin oxide(ITO) conductive glass substrates was successfully prepared via a facile one-step hydrothermal process, where titanium butoxide used as Ti source and HCl as an acidic medium solution. The as-obtained products were characterized by X-ray diffraction(XRD), field emission scanning electron microscopy(FE-SEM), transmission electron microscopy(TEM), selected area electron diffraction(SAED) and applied in gas sensor. The characterization of FE-SEM indicates that the morphology of the products can be controlled by regulating solution acidity, the amount of titanium butoxide, reaction time, addition agents, and so on. The gas sensing test shows that the sensor fabricated with 3D nanotree-like rutile TiO_2 has higher gas response towards CH3 COCH3 gas than those with 1 D rod-like TiO_2 or common TiO_2 precipitate, indicating that the 3D nanotree-like architectures may be promising gas sensitive materials.     

微波辅助合成石墨烯/氧化镍复合材料及其表征

本文通过微波辅助的方法,快速而有效地在热膨胀石墨烯(RG)的缺陷上原位合成氧化镍纳米颗粒,形成石墨烯/氧化镍复合材料(RG/NiO)。利用X-射线衍射(XRD),拉曼光谱(Raman),傅里叶变换红外(FTIR),扫描电镜(SEM),透射电镜(TEM),热重-差热(TGA-DSC)对所制备样品的结构、形貌和NiO含量在复合材料中的含量进行表征。结果表明,热膨胀石墨烯层数约7~8层,层间距约为0.35nm,缺陷多,在水热和微波处理后抗氧化性明显变差。复合材料中氧化镍颗粒平均粒径为25nm,均匀而密集地分散在石墨烯平面上,同时在复合材料中的含量为19.8%。     

Synthesis and Characterization of a Novel Zeolite CJS-4

A novel zeolite, denoted as CJS-4, has been synthesized from nonalkaline medium by using 4,4'-trimethylenebis(1-methylpiperidine) or 1,4-diazoniabicyclo(2,2,2) octane as template agent, respectively. The precursors were characterized by means of powder X-ray diffraction, scanning electron microscopy, thermal analysis, gas adsorption and high resolution solid state NMR of 13C and 29Si.     

Synthesis of nanometer-sized sodalite without adding organic additives

Aggregates (80 nm) of sodalite nanocrystals with crystallite sizes ranging from 20 to 40 nm have been synthesized from a sodium aluminosilicate solution at low temperature, without adding any organic additives, while paying attention to the key factors for the synthesis of nanosized zeolite crystals. The physical properties of nanosized sodalite crystals were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, 29Si solid-state magic-angle spinning (MAS) NMR, and N2 adsorption. As expected, the external surface area of nanosized sodalite crystals is significantly increased compared with that of microsized sodalite crystals. The size of synthesized sodalite crystals can be controlled from 20 nm to 10 microm. It is found that the preparation of a homogeneous aluminosilicate solution followed by the formation of an aluminosilicate hard gel by adjusting the initial composition, for example, SiO2/Al2O3 and Na2O/H2O ratios, is critical for synthesis.