Adsorptive desulfurization by copper species within confined space

Copper species were incorporated into SBA-15 by solid-state grinding precursor with as-prepared mesoporous silica (SPA). The obtained materials (CuAS) were well-characterized by XRD, TEM, N(2) adsorption, H(2)-TPR, IR, and TG and compared with the material derived from calcined SBA-15 (CuCS). Surprisingly, CuO up to 6.7 mmol·g(-1) can be highly dispersed on SBA-15 by use of SPA strategy. Such CuO forms a smooth layer coated on the internal walls of SBA-15, which contributes to the spatial order and results in less-blocked mesopores. However, the aggregation of CuO takes place in CuCS material containing 6.7 mmol·g(-1) copper, which generates large CuO particles of 21.4 nm outside the mesopores. We reveal that the high dispersion extent of CuO is ascribed to the abundant silanols, as well as the confined space between template and silica walls provided by as-prepared SBA-15. The SPA strategy allows template removal and precursor conversion in one step, avoids the repeated calcination in conventional modification process, and saves time and energy. We also demonstrate that the CuAS material after autoreduction exhibits much better adsorptive desulfurization capacity than CuCS. Moreover, the adsorption capacity of regenerated adsorbent can be recovered completely.     

Synthesis, characterization and visible light photocatalytic properties of Bi2WO6/rectorite composites

Visible light-induced Bi(2)WO(6)/rectorite (BR) composites were prepared by a sol-gel method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectrum, Fourier transform infrared (FTIR) spectrum, X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmet-Teller (BET). The UV absorption edges of the BR-450 catalyst showed a marked red shift as compared to that of the pure Bi(2)WO(6). The photocatalytic activities of the as-prepared samples were evaluated by the photocatalytic degradation of 4BS dye in aqueous solution under visible light irradiation (>420 nm). The results showed that the BR-450 catalyst exhibited a strong adsorption capability and a higher photocatalytic degradation activity than the pure Bi(2)WO(6) for 4BS dye, which could be attributed to the synergetic effects of the adsorbability of rectorite and the photocatalytic property of Bi(2)WO(6) in it.     

不同形貌WO3的水热合成及其在水处理中的应用研究

三氧化钨(WO₃)以其较窄的带隙,成为继二氧化钛(TiO₂)之后颇具发展潜力的n型半导体光催化剂.本文采用水热合成法,通过调控反应参数,如原料组成、沉淀时间等,合成了不同形貌和晶型的WO₃;采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、傅里叶变换红外光谱(FT-IR)、氮气吸附-脱附(N₂ adsorption-desorption)等表征了所合成的WO₃产品,发现原料组成、沉淀时间等条件对WO₃的晶型和形貌都有影响;研究了所合成的WO₃产品去除水中亚甲基蓝染料污染物的性能,结果表明,所制备的WO₃对水中亚甲基蓝具有较好的去除效果,去除率可达97%.     

Growth of porous single-crystal Cr2O3 in a 3-D mesopore system

Single-crystal Cr2O3 with regular mesopores has been synthesized using mesoporous silica KIT-6 as a template and characterized by using XRD, HRTEM and nitrogen adsorption/desorption.     

多级孔NaX分子筛的合成及CO2吸附性能

采用两步晶化和氨基酸辅助的协同合成策略, 制备了具有高产率(89%)和高结晶度(微孔体积为0.30 cm ³/g)的多级孔NaX分子筛. 利用X射线粉末衍射、 扫描电子显微镜、 透射电子显微镜和氮气吸附等技术, 考察了两步晶化和氨基酸加入量对NaX分子筛的形貌、 相对结晶度和产率的影响. 实验结果表明, 两步晶化有利于多级孔结构的产生, 氨基酸的引入有助于提高分子筛相对结晶度和产率. 与传统方法合成的NaX分子筛相比, 该合成策略制备的多级孔NaX分子筛展现出更优异的CO₂吸附性能, 在273 K和100 kPa条件下, 其CO₂吸附量达到154.2 cm ³/g, 而传统NaX分子筛的CO₂吸附量为147.6 cm ³/g. 该合成策略为绿色且高效制备高质量的多级孔分子筛提供了新思路.     

Saucer-and Rod-like WO_3 3-D Microstructures:Synthesis,Characterization,and Optical Properties

Three-dimensional(3-D)saucer-and rod-like WO3 microstructures have been synthesized by a simple hydrothermal route using tartaric acid as the assistant agent.X-ray powder diffraction(XRD)patterns indicate that the as-prepared samples are the pure hexagonal phase WO3.The morphologies are characterized by scanning electron microscope(SEM)and are found to be highly sensitized to the reaction temperature.A probable formation mechanism of the WO3 microstructures from saucer-like at low temperatures to rod-like at high temperatures is proposed.The optical properties of the novel WO3 microstructures are studied by UV-vis diffuse reflectance spectroscopy(DRS).The mechanism of strong absorption at visible region and red shift of calcined sample is also discussed.     

Easy replication of Pueraria Lobata toward hierarchically ordered porous gamma-Al2O3

Hierarchically ordered porous alumina was prepared via a facile immersion-fuming-calcination process using Pueraria lobata as template. The as-prepared alumina inherited nearly all morphological features of the template, as shown by SEM observations. It also contains abundant mesopores based on nitrogen adsorption-desorption measurements. The crystalline phase of the as-prepared alumina was ascertained to be gamma-alumina by analyzing its XRD pattern. Pt nanoparticles were in situ synthesized in the gamma-alumina matrix and annealed at different temperatures in N(2) atmosphere. TEM observations showed that Pt nanoparticles supported by the as-prepared alumina have significantly high thermal stability.     

Controllable synthesis and tunable luminescence properties of Y2(WO4)3:Ln3+ (Ln = Eu, Yb/Er, Yb/Tm and Yb/Ho) 3D hierarchical architectures

Yttrium tungstate precursors with novel 3D hierarchical architectures assembled from nanosheet building blocks were successfully synthesized by a hydrothermal method with the assistance of sodium dodecyl benzenesulfonate (SDBS). After calcination, the precursors were easily converted to Y(2)(WO(4))(3) without an obvious change in morphology. The as-prepared precursors and Y(2)(WO(4))(3) were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectra, respectively. The results reveal that the morphology and dimensions of the as-prepared precursors can be effectively tuned by altering the amounts of organic SDBS and the reaction time, and the possible formation mechanism was also proposed. Upon ultraviolet (UV) excitation, the emission of Y(2)(WO(4))(3):x mol% Eu(3+) microcrystals can be tuned from white to red, and the doping concentration of Eu(3+) has been optimized. Furthermore, the up-conversion (UC) luminescence properties as well as the emission mechanisms of Y(2)(WO(4))(3):Yb(3+)/Ln(3+) (Ln = Er, Tm, Ho) microcrystals were systematically investigated, which show green (Er(3+), (4)S(3/2), (2)H(11/2)→(4)I(15/2)), blue (Tm(3+), (1)G(4)→(3)H(6)) and yellow (Ho(3+), (5)S(2)→(5)I(8)) luminescence under 980 nm NIR excitation. Moreover, the doping concentration of the Yb(3+) has been optimized under a fixed concentration of Er(3+) for the UC emission of Y(2)(WO(4))(3):Yb(3+)/Er(3+).     

增强光催化活性的3D分级结构Bi2W06微球及表面酸性

以KNO3为矿化剂,用水热法制备了3D分级结构Bi2WO6微球,通过XRD、SEM、BET对产物进行了表征．探讨了3D分级结构Bi2WO6微球可能的形成机理．以罗丹明B为模型污染物,研究了合成产物的光催化性质．结果表明：在紫外光下,RhB的降解以共轭结构断裂的光催化反应为主;而在可见光照射下,RhB的降解可能是光催化和光敏化共同作用的结果．进一步以吡啶为探针分子,通过吸附吡啶红外光谱探讨了Bi2W06表面酸性与光催化降解RhB之间的关系．研究显示,Bi2W06具有较强的表面酸性,增强了Bi2WO6与RhB分子之间吸附作用,有利于染料分子上的电子跃迁至催化剂上,易于发生光敏化和光催化反应。     

新型纳米层状硅酸盐Magadiite主体材料的制备、表征、结构和生成机理研究

利用简单的插层反应方法成功地制备了四丁基氢氧化铵(TBAOH)插层的层状硅酸盐Magadiite纳米复合材料,在室温下该材料溶胶放置30d可以保持稳定,粉体长期保存结构稳定,而且反应时间短,只需30min.利用XRD,FTIR,SEM和HRTEM等方法对样品进行了结构表征.结果表明,TBA⁺离子在层间以双分子层排列,并与层状硅酸盐结合在一起,TBAOH插层后的纳米粒子在玻璃片上进行了重组,粒径分布在10～100nm之间;HRTEM电镜照片进一步证实了剥离的层状硅酸盐纳米粒子在玻璃片上的自组装过程.根据实验结果阐述了TBAOH插层反应形成纳米溶胶的机理.     

Long TiO2 hollow fibers with mesoporous walls: sol-gel combined electrospun fabrication and photocatalytic properties

Long TiO2 hollow fibers with mesoporous walls have been fabricated with the sol-gel combined two-capillary spinneret electrospinning technique using a triblock copolymer (Pluronic, P123, (H(C2H5O)20(C3H7O)70 (C2H5O)20OH) as a pore-directing agent. The as-prepared hollow fibers were as long as 30 cm with an outer diameter of 0.1-4 microm and wall thickness of 60-500 nm. The diameters and wall thicknesses of the hollow fibers could be tuned by adjusting the electrospinning parameters. The fiber walls were composed of mesopores 6.7 nm in diameter as calculated from the N2 adsorption/desorption isotherm. The high-resolution TEM (HR-TEM) images exhibited that the mesopores were hexagonally aligned with a low order because of the curving of the pores. When comparing with other nanostructured TiO2 materials such as commercial TiO2 nanoparticles (P25, Degussa) and mesoporous TiO2 powders, the hollow fibers exhibited higher photocatalytic activities toward degradation of methylene blue and gaseous formaldehyde.     

Synthesis of visible-light-driven TiO2 yolk-shell spheres with {0 0 1} facets dominated mesoporous shells

Anatase phase visible-light-driven TiO2 yolk-shell spheres with the size of ca. 1-2 μm have been synthesized with the combination of solvothermal and heat treatment method. XRD, SEM, TEM, XPS, and PL analysis were used to examine structure and properties of the photocatalyst. The N species and Ti3+ centers introduced into the as-prepared photocatalyst can enhance the visible light absorption significantly. The mesoporous shell of the prepared photocatalyst, which promotes the pollutant adsorption ability, consists of the high-reactive {0 0 1} facets dominated nanocrystals. Due to the unique structure, it is also observed that the as-prepared visible-light-driven TiO2 yolk-shell spheres exhibit a superior photocatalytic activity for organic dyes decomposition than the well-known P25.     

氧掺杂对VN-g-C3N4催化剂光催化固氮性能的影响

采用介质阻挡放电等离子体法合成了氧原子掺杂的具有氮空穴的石墨相氮化碳催化剂(g-C₃N₄), 并对催化剂的结构和形貌进行了表征分析. 结果表明, 等离子体处理没有改变催化剂的形貌, 并同时将氮空穴和氧原子引入了g-C₃N₄的晶格. 在可见光条件下, 制备的共掺杂g-C₃N₄催化剂的铵离子产率高达5.9 mg·L ^-1·h ^-1· {\mathrm{g}}_{\mathrm{cat}}^{-1} , 分别是具有氮空穴的g-C₃N₄和纯g-C₃N₄的2.2倍和20倍, 同时还表现出优异的催化稳定性. 密度泛函理论计算结果显示, 与具有氮空穴的g-C₃N₄相比, 氧原子的引入能提高氮空穴对反应物氮气分子的活化能力, 提高光催化固氮性能.     

Functionalization of tungsten oxide into MWCNT and its application for sunlight-induced degradation of rhodamine B

A composite of multi-walled carbon nanotube/tungsten oxide (MWCNT/WO(3)) has been successfully synthesized. The prepared composite was characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), high-resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR). The catalytic activity was investigated by rhodamine B degradation under solar irradiation. The influence of various degradation parameters such as solar illumination time, initial dye concentration, dosage and pH was investigated. It was found that the composite exhibits an enhanced photocatalytic activity as compared with WO(3) and a mechanical mixture of MWCNTs and WO(3). The enhancement in photocatalytic performance of the MWCNT/WO(3) composite has been explained based on adsorption ability and electron transportation as a result of a strong interaction between WO(3) and MWCNTs. Besides, MWCNTs acts as dispersing agent preventing WO(3) from agglomerating during the catalytic process, providing a high active surface area of the catalyst. A reasonable mechanism for the enhanced reactivity was proposed.     

WO3/TiO2 复合纤维的制备及储能光催化性能

以钛酸正丁酯为前驱体, 采用静电纺丝技术制得了纯锐钛矿TiO2纤维, 并以其为基质, 通过水热法制备了具有异质结构的WO3/TiO2复合纤维. 利用X射线衍射仪(XRD)、 扫描电子显微镜(SEM)、 能量色散光谱仪(EDS)、 透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)等对样品的结构和形貌进行了表征. 以罗丹明B的脱色降解为模型反应, 考察了样品的光催化性能和储能光催化性能. 结果表明, 花状WO3微球包裹在TiO2纤维上, 得到了具有异质结构的WO3/TiO2复合纤维光催化剂. WO3与TiO2复合有利于光生载流子的输运和分离, 增强了体系的量子效率, 提高了光催化活性. WO3/TiO2 复合纤维经光照处理后, 在黑暗条件下显示出储能光催化特性.     

一步由微米铝球直接合成含笼状大孔的Al-SBA-15

以微米铝球为铝源,正硅酸乙酯(TEOS)为硅源,聚醚三嵌段聚合物P123为模板剂,在酸性水溶液中,一步直接合成含有笼状大孔的介孔氧化硅(铝)分子筛Al-SBA-15.用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、27Al固体核磁(27AlMAS-NMR)、ICP发射光谱仪、X射线衍射(XRD),以及低温N2吸/脱附对样品进行了表征.结果表明,得到的材料是二维六方结构(空间群p6mm)的Al-SBA-15,经过550℃焙烧后,Al-SBA-15的比表面积大约为500m2/g,Si/Al比在40～80之间,四配位铝/六配位铝之比约为2,结构中存在约70～80nm的笼型大孔和约为5nm的介孔.     

柠檬酸溶胶-凝胶法制备的纳米Ce1－xMnxO2: 织构与晶相结构

采用N2-吸附/脱附、XRD、Raman光谱和TEM等表征技术研究了柠檬酸溶胶-凝胶法制备的Ce1－xMnxO2 (0≤x≤1) 样品的织构及晶相结构.结果表明, Ce1－xMnxO2 样品的N2吸附等温线为IV型, 滞后环为H1型, 最可几孔径处在2.5~3.7 nm范围.由XRD测得的样品晶粒大小与由TEM测定的颗粒尺寸相近, 表明制备的样品具有较好的分散性, 但是样品的组成对颗粒大小有明显的影响, Mn浓度适中样品(x=0.3~0.7)的颗粒(1~5 nm)明显小于低Mn浓度样品(x<0.3)和高Mn浓度样品(x>0.7)的颗粒(10~50 nm).尽管在x>0.7时, XRD未能检测到样品中有α-Mn2O3晶粒存在, 但Raman光谱结果表明, 所有Ce1－xMnxO2混合氧化物均以α-Mn2O3相和立方CeO2相Ce-Mn-O固溶体形式存在.     

Effect of calcination temperature on the surface morphology and crystallinity of tungsten (VI) oxide nanorods prepared using colloidal gas aphrons method

The effect of calcination temperature on the surface morphology and crystallinity of tungsten (VI) oxide, WO₃ nanorods prepared using colloidal gas aphrons (CGAs) as template was studied. The synthesized WO₃ nanorods were calcined in a furnace for 4 h at four different temperatures, i.e., 400, 500, 600 and 700 °C. The morphology of the calcined WO₃ nanorods have been characterized by both transmission electron microscope (TEM) and variable pressure scanning electron microscope (SEM) equipped with energy dispersive X-ray analysis (EDAX). The results showed that the calcination temperature influenced the shape and size of the WO₃ nanorods produced. It is also found that the calcination at various temperature do not effect the composition and the purity of the WO₃ nanorods. In order to characterize the crystalinity of WO₃, X-ray diffraction (XRD) has been used. It shows that all the calcined WO₃ produced are in crystalline form compared to the as-prepared WO₃ nanorods, which is in amorphous form.     

One-step fabrication and high photocatalytic activity of porous TiO2 hollow aggregates by using a low-temperature hydrothermal method without templates

Porous TiO2 hollow aggregates have been synthesized on a large scale by means of a simple hydrothermal method without using any templates. The as-prepared products were characterized by means of field emission scanning electron microscopy, XRD, TEM, nitrogen adsorption, UV/Vis diffuse reflectance spectroscopy, and FTIR spectroscopy. The photocatalytic activity of the aggregates was demonstrated through the photocatalytic degradation of Rhodamine B. Structural characterization indicates that the porous TiO2 aggregates are 500-800 nm in diameter and display mesoporous structure. The average pore sizes and BET surface areas of the aggregates are 12 nm and 168 m2 g-1, respectively. Optical adsorption investigations show that the aggregates possess an optical band-gap energy of 3.36 eV. The as-prepared products were substantially more effective photocatalysts than the commercially available photocatalyst P25. The dye degradation rate of the porous TiO2 hollow aggregates is more than twice that of P25. The high photoactivities of the aggregates can be attributed to the combined effects of several factors, namely, large surface areas, the existence of mesopores, and the high band-gap energy. In addition, the as-prepared products can be easily recycled.     

具有结晶孔壁介孔镁锌氧复合物(英文)

以介孔碳为硬模板经过二次填充制备了介孔镁锌氧复合物.采用X射线衍射(XRD),透射电镜(TEM),扫描电镜(SEM),N2吸附脱附等手段对材料的结构及形貌进行了表征.结果表明,所制备的材料在具有高有序介孔结构的同时还具有结晶的孔壁.孔径尺寸均为4.0nm,比表面积均为114.5m2.g-1.广角XRD结果初步表明,材料中氧化镁和氧化锌复合形成了固溶体.该材料作为一种半导体材料有望在光学器件领域获得新的应用价值.