TiO_2-SiO_2光催化剂的合成及其对罗丹明B的光催化降解

采用两步模板法,通过制备二氧化硅胶体晶体模板,以钛酸异丙酯为钛源和三嵌段共聚物P123为介孔导向合成介孔钛硅氧化物光子晶体微球光催化剂。采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)对制得的薄膜材料的结构进行表征。结果表明,介孔复合薄膜中锐钛矿型TiO2纳米粒子均匀排列。以罗丹明B为模型物,考察其在紫外光区的光催化活性。结果表明,钛硅氧化物光催化剂降解效果比普通TiO2薄膜有所提高。     

超亲水性含钛介孔SiO2薄膜的制备及其自洁净性能研究

采用溶胶-凝胶/旋转涂覆法在玻璃基板表面制备含钛介孔SiO2薄膜.利用XRD、UV-Vis以及接触角测量仪对薄膜的孔结构和超亲水性进行表征.结果表明,当Ti/Si物质的量比为0～0.05时,薄膜均具有良好的介孔结构;而随着Ti/Si物质的量比的增加,薄膜的介孔有序度下降.即使在无光照条件下,含钛介孔SiO2薄膜也表现出高效的超亲水性.涂有油酸的薄膜在紫外光照射后恢复其超亲水性,且薄膜对甲基橙具有良好的光催化降解效果,表明制备的含钛介孔SiO2薄膜具有良好的自洁净性能.     

光催化制备结晶TiO_2介孔薄膜及其性能表征(英文)

提出了一种在室温条件下制备结晶TiO2介孔薄膜的简便方法。首先采用含有罗丹明B的TiO2纳米晶溶胶通过浸渍提拉制备结晶TiO2薄膜,然后将薄膜置于紫外灯下照射,通过TiO2薄膜自身的光催化作用将薄膜中的罗丹明B分解去除,从而形成介孔薄膜。分别采用X射线衍射仪、扫描电子显微镜和透射电子显微镜对样品进行了表征,并考察了薄膜对水的接触角及光催化活性。结果表明:所制备的TiO2介孔薄膜由30～50nm的纳米粒子组成,其晶型为锐钛矿-板钛矿-金红石混晶;适当的罗丹明B添加量有利于介孔形成;由于介孔的作用,TiO2介孔薄膜的亲水性及光催化活性相对于致密TiO2薄膜有显著提高。     

有序介孔二氧化硅薄膜的制备及性能

以十六烷基三甲基溴化铵(CTAB)为模板剂,正硅酸乙酯为无机前驱体,在酸性条件下,采用溶胶-凝胶技术,用蒸发诱导自组装(EISA)工艺制备了二氧化硅透明介孔薄膜. 透射电子显微镜图显示热处理后的薄膜具有高度有序的六方相结构孔道;由椭偏仪测得热处理后薄膜的折射率低至1.18,厚度在180 nm左右;阻抗分析仪测得薄膜的介电常数为2.14. 薄膜经过六甲基二硅胺烷(HMDS)表面修饰后具有良好的疏水性能和热稳定性,作为低介电材料能更好满足工业需求.     

超敏感的ZnO镀覆传感器在室温下对甲醛的影响

在本工作中,用介孔结构的甲醛传感器在室温下检测了甲醛(十亿分之几)浓度。通过X-射线衍射(XRD)、Brunauer Emmett Teller(BET)和扫描电子显微镜(SEM)检测介孔氧化锌的形态和结构。测试了甲醛、甲醇、乙醇、丙酮和丙酮的传感特性。气体传感研究表明,介孔氧化锌在室温下对浓度为0.037 mg/m~3的甲醛具有极好的敏感性。因此,介孔氧化锌在甲醛传感器领域有着广阔的应用前景。     

微波法合成Cu-MCM-41介孔分子筛的研究

以硅酸钠、氯化铜等无机盐为原料,十六烷基三甲基溴化铵(CTAB)为模板剂,通过微波辐射方法合成不同铜含量的Cu-MCM-41介孔分子筛。分别采用X射线粉末衍射(XRD)、透射电子显微镜(TEM)和N2吸附-脱附等技术对产物的晶相、结构、形貌、比表面积和孔径分布进行表征。结果表明,通过微波辐射方法成功地合成出含有不同孔径的Cu-MCM-41介孔分子筛。随着原料配比中n(CuO)∶n(S iO2)(摩尔比)的增加,介孔分子筛的比表面积和孔体积变小,介孔有序性变差。     

桥连双亚胺介孔材料的制备及其表征

以自制双亚胺硅烷偶联剂和正硅酸乙酯为硅源,十六烷基三甲基溴化铵(CTAB)/聚丙烯酸钠(PAANa)为混合模板剂,通过共缩聚法合成桥连双亚胺席夫碱功能化介孔材料。利用红外光谱(FTIR)、氮气吸附-脱附、X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对桥连双亚胺介孔材料进行了表征,着重探讨了不同PAANa用量对介孔材料的结构和形貌的影响,并将其应用于重金属离子的吸附。结果表明,PAANa用量对桥连双亚胺介孔材料的比表面积、孔容积和有序度都有一定的影响;当PAANa的加入量为0.01%时,功能化介孔材料(PMOS_(0.01))展现出较好的形貌、有序度和比表面积。此外,在酸性条件下,PMOS_(0.01)对Cr(Ⅵ)的吸附量为289.24mg/g;而在碱性条件下,PMOS_(0.01)对Cu(Ⅱ)的吸附量为276mg/g。     

电子显微镜研究分子筛的新进展

电子显微镜在沸石分子筛的研究中起着重要的作用.阐述了透射电子显微镜(TEM)和扫描电子显微镜(SEM)技术研究沸石分子筛的原理,描述了使用不同种类的电子显微镜剖析沸石分子筛的形态、尺寸、粒径分布等,并介绍了近年来电镜技术对沸石分子筛,特别是对新型功能介孔材料及手性介孔材料的研究进展.电子显微镜的发展将推动分子筛及纳米材料在选择性催化/吸附过程中的应用.     

有序介孔铁氧化物催化过氧化氢降解水中诺氟沙星

以介孔材料SBA-15为模版,采用硬模版法制备了有序介孔氧化铁,并对其催化过氧化氢(H2O2)降解水中有机污染物效能与机理进行了研究。采用X射线衍射(XRD)、透射电子显微镜(TEM)、氮气吸附-脱附、X射线荧光(XRF)、X射线光电子能谱(XPS)等分析手段对介孔氧化铁进行表征。以诺氟沙星为目标物,利用介孔氧化铁催化H2O2降解水中有机污染物效能,研究了溶液初始p H、H2O2初始投加量和催化剂初始投加量对反应的影响。通过叔丁醇(TBA)、对苯醌(p-BQ)的抑制实验对反应机理进行了讨论。     

钙掺杂的多孔TiO_2的制备及其光催化性能研究

采用溶剂蒸发自组装法(EISA)制备了钙掺杂的多孔TiO_2薄膜,以聚苯乙烯(PS)微球、聚醚P123分别为大孔和介孔导向剂。通过SEM、TEM、XRD、PL、比表面积分析法及紫外-可见分光光度法对材料形貌、结构、光降解性能进行了表征。研究了不同含量的Ca掺杂样品在紫外光区对罗丹明B(RhB)的光降解性能。实验结果表明,掺杂少量的Ca可以显著提高大孔-介孔TiO_2薄膜材料的光催化活性,且当掺Ca量为0.25%时,多孔TiO_2对RhB的光催化活性最大。     

Ce-MCM-22分子筛的合成与吸附性能

采用静态水热晶化法,以硅溶胶为硅源、六亚甲基亚胺(HMI)为模板剂,通过掺杂Ce合成了具有MWW层状结构的Ce-MCM-22分子筛.利用粉末X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)等方法对其进行了表征,考察了各种因素对Ce-MCM-22分子筛吸附亚甲基蓝溶液的影响,结果表明当Ce-MCM-22分子筛的投加量为0.6 g/L,亚甲基蓝浓度为2.0 mg/L,pH值为7,震荡60 min时,吸附脱色效果较好.     

T-ZnO_w-TiO_2/PMMA复合半导体膜的制备及其光催化性能的研究

将经去离子水处理陈化后的锌粉与沸石混合后在950℃下煅烧制备了四针状氧化锌晶须(T-ZnOw)。以SEM、TEM、SRD、UV-Vis等对T-ZnOw的形貌、可见-紫外光特性进行了表征;将其掺杂于锐钛矿型的TiO2中,负载于聚甲基丙烯酸甲酯(PMMA)薄膜上,测试其光催化性能。结果表明:T-ZnOw-TiO2/PMMA纳米复合材料较单一的ZnO/PMMA和TiO2/PMMA显示出更高的光催化降解亚甲基蓝的活性,紫外光照60min后降解率高达98%。     

Influence of postdeposition annealing on the properties of ZnO films prepared by RF magnetron sputtering

ZnO films were prepared on unheated silicon substrate by RF magnetron sputtering technique. Postdeposition annealing of ZnO films in vacuum were found to improve film structure and electrical characteristics, such as dense structure, smooth surface, stress relief and increasing resistivity. Suitable annealing temperature also reduced loss factor. The correlation between annealing conditions and the physical structure of the films (crystalline structure and microstructure) was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The preferred annealing condition has been found to improve ZnO film characteristics for piezoelectric applications. An over-mode acoustic resonator using the ZnO film after annealing at 400 °C in vacuum circumstance for 1 h showed a large return loss of 42 dB at the center frequency of 1.957 GHz.     

Structural and thermal studies of silver nanoparticles and electrical transport study of their thin films

This work reports the preparation and characterization of silver nanoparticles synthesized through wet chemical solution method and of silver films deposited by dip-coating method. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and energy dispersive spectroscopy (EDX) have been used to characterize the prepared silver nanoparticles and thin film. The morphology and crystal structure of silver nanoparticles have been determined by FESEM, HRTEM, and FETEM. The average grain size of silver nanoparticles is found to be 17.5 nm. The peaks in XRD pattern are in good agreement with that of face-centered-cubic form of metallic silver. TGA/DTA results confirmed the weight loss and the exothermic reaction due to desorption of chemisorbed water. The temperature dependence of resistivity of silver thin film, determined in the temperature range of 100-300 K, exhibit semiconducting behavior of the sample. The sample shows the activated variable range hopping in the localized states near the Fermi level.     

Physicochemical and morphological evaluation of chitosan/poly(vinyl alcohol)/methylcellulose chemically cross-linked ternary blends

Chitosan/poly(vinyl alcohol)/methylcellulose (CS/PVA/MC) ternary blend was prepared and chemically cross-linked with glutaraldehyde. The prepared ternary blends were characterized by Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The FTIR results showed that the strong intermolecular hydrogen bonds took place between CS and PVA. TGA showed the thermostability of the blend is enhanced by glutaraldehyde as crosslink agent. Results of XRD indicated that the relative crystalline of pure CS film was reduced when the polymeric network was reticulated by glutaraldehyde. Finally, the results of scanning electron microscopy (SEM) indicated that the morphology of the blend is rough and heterogenous, further it confirms the interaction between the functional groups of the blend components.     

Characterization of silicon films grown by atomic layer deposition on nanocrystalline diamond

Ultrathin silicon films were deposited on nanocrystalline diamonds by means of atomic layer deposition (ALD) from gaseous monosilane. The silicon deposition was achieved through the sequential reaction of SiH₄ saturated adsorption and in-site pyrogenation. X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution electron microscopy (HREM) and Fourier transform infrared (FTIR) spectra were utilized to investigate the structure and the morphology of Si-coated nanocrystalline diamonds. The results confirmed that continuous silicon films were successfully deposited on both basal planes and edges of nanocrystalline diamond particles by this ALD method and the structure of the film was mainly determined by deposition temperature and deposition cycle.     

Thermal annealing effects on the structural and electrical properties of PMN–PZ–PT ternary thin films deposited by a sol–gel process

Thin film samples of 0.15PMN–0.45PZ–0.40PT (PMN–PZ–PT) three-component system were prepared on Pt-coated Si substrates by a sol–gel process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), and secondary ion mass spectrometry (SIMS) show that the above films can be formed in a single-phase perovskite structure at 800 °C. This was further confirmed by the dielectric and ferroelectric properties of the samples annealed at different temperatures. It was demonstrated that the morphology and microstructures of the PMN–PZ–PT films were quite sensitive to their annealing conditions, which strongly affects their electrical properties.     

Metal copper films coated on microparticle substrates using an ultrasonic-assisted magnetron sputtering system

Metal copper films were coated on micrometer silicon carbide (SiC) and polymer particles with different sizes using the ultrasonic-assisted magnetron sputtering system. The surface morphology, the chemical composition and the crystallization of the SiC and the polymer particles were characterized by the field emission scanning electron microscopy (FE-SEM), energy dispersive analysis of X-rays (EDAX) and X-ray diffraction (XRD) analysis before and after film deposition. The experiment results indicate that the copper films were successfully coated on SiC and polymer particles. The XRD results show that the copper films have a face centred cubic structure. It was found from the FE-SEM results that film growth of copper films is a three-dimensional island growth mode.     

Morphological and Thermal Properties of Poly(amide-imide)/ZnO Nanocomposites Derived from 4,4′-methylenebis(3-chloro-2,6-diethyl trimellitimidobenzene) and 3,5-diamino-N-(4-hydroxyphenyl)benzamide

A new nanostructure poly(amide-imide) (PAI) was prepared from the polymerization of 4,4′-methylenebis(3-chloro-2,6-diethyl trimellitimidobenzene) as a diacid with 3,5-diamino-N-(4-hydroxyphenyl)benzamide using triphenyl phosphite as a condensing agent and tetra-n-butylammonium bromide as a green media. The synthesized polymer was used to prepare PAI/ZnO nanocomposites (PZNC)s using nano-ZnO surface-coupled by N-trimellitylimido-L-alanine diacid as a coupling agent through ultrasonic process. The resulting PZNCs were also characterized by FT-IR, powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The TEM and FE-SEM results showed a good dispersion of nanoscale inorganic particles in the polymer matrix.     

Novel high-strength montmorillonite/polyvinyl alcohol composite film enhanced by chitin nanowhiskers

Nanomaterials can be used as reinforcement phase to improve the performance of polymers. A simple method to prepare a composite film with super high tensile strength was used in this study. The properties of montmorillonite (MMT)/polyvinyl alcohol (PVA) films reinforced by chitin nanowhisker (CNW) have been evaluated. The structures and properties of films were analyzed by atomic force microscope (AFM), Fourier transforms infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and tensile testing. The results of FTIR and XRD showed that no chemical interaction occurred among MMT, PVA, and CNW. The SEM and AFM images suggested that the obtained composite films with the three substances had a relatively uniform layered structure and relatively smooth. The temperature at the onset of decomposition of the composite films was increased from 262.0 to 282.3°C by the addition of CNW. The tensile strength of the MMT/PVA/CNW film was reached 263.5 MPa, which was increased approximately 382% compared with the MMT/PVA film. According to these results, the composite film could be potentially used in packaging materials.