氧化锌纳米晶的制备及光催化性能研究

采用沉淀-热分解方法制备纳米ZnO,并用场发射扫描电子显微镜和X-射线衍射仪分析所制备的ZnO粉体的晶粒大小和物相,同时研究了在不同煅烧温度下制备的纳米ZnO对次甲基蓝的光催化降解效率.实验结果表明:在450 ℃下煅烧2 h制备的ZnO粉体的粒径基本分布在20～40 nm的范围内,且具有(假)六方结构.将在400 ℃和500 ℃下合成的ZnO纳米晶相比,在450 ℃下合成的样品对次甲基蓝的光催化降解效率较高;此外,外加适量的30%H2O2(质量含量,下同)溶液能显著提高纳米ZnO对次甲基蓝的光催化降解效率.     

纳米ZnO的制备及其光催化性能研究

本文以羟丙基纤维素（HPC）作为分散剂,运用沉淀法制备出了粒径均匀的ZnO颗粒.通过透射电子显微镜（TEM）,X射线衍射（XRD）,紫外可见光吸收光谱,光致发光谱（PL）对ZnO进行了性能表征,并探讨了其形成机理及制备中的影响因素.利用纳米ZnO作为光催化剂对有机染料罗丹明B进行了光降解实验,实验结果表明,此方法制备的ZnO具有良好的光催化性能,有望在治理环境污染等领域具有良好的应用.     

PET/ZnO纳米复合材料的制备及结晶性能

通过纳米ZnO存在下的对苯二甲酸／乙二醇(TPA／EG)酯化和缩聚反应制备聚对苯二甲酸乙二醇酯(PET)／ZnO纳米复合材料，研究了纳米ZnO用量及其分散方式对PET粘均摩尔质量、纳米ZnO在复合物中的分散及聚乙二醇(PEG)结晶性能的影响。发现纳米ZnO及分散改性剂(PEG)的加入，对合成PET的粘均摩尔质量均有一定影响；纳米ZnO在EG中直接分散再缩聚形成的复合物中，纳米ZnO团聚严重、分散性差，PET的结晶度和结晶速率降低；在纳米ZnO分散过程中加入PEG可以降低纳米ZnO在复合物中的团聚，提高分散性，PET的结晶度和结晶速率提高。     

Characterization and Optical Properties of the Single Crystalline SnS Nanowire Arrays

The SnS nanowire arrays have been successfully synthesized by the template-assisted pulsed electrochemical deposition in the porous anodized aluminum oxide template. The investigation results showed that the as-synthesized nanowires are single crystalline structures and they have a highly preferential orientation. The ordered SnS nanowire arrays are uniform with a diameter of 50 nm and a length up to several tens of micrometers. The synthesized SnS nanowires exhibit strong absorption in visible and near-infrared spectral region and the direct energy gap E _g of SnS nanowires is 1.59 eV.     

共掺杂ZnO纳米材料的制备及光学性能研究

利用共沉淀法制备了Y和Cd共掺杂的ZnO纳米材料。X-射线衍射分析表明,样品为单一相的ZnO纤锌矿结构,随着掺杂量的增加,样品的晶粒尺寸减小。光学性能测试结果表明,样品具有较强的紫外发射峰和较弱的可见光发射峰,紫外发射峰强度随着掺杂量的增加而减弱并发生红移。     

ZnO/AgBr复合纳米棒的制备及其光催化性能研究

以ZnNO3·6H2O、AgNO3、十六烷基三甲基溴化铵和氨水为原料,通过水热法制备了ZnO/AgBr复合纳米棒.利用SEM、XRD分别对产品的形貌和结构进行表征.以ZnO/AgBr复合纳米棒为光催化剂,通过降解有机污染物甲基橙进行了光催化活性测试,结果表明,在可见光照射150 min后,对甲基橙的降解率接近完全.     

纳米ZnO的制备及气相光催化性能研究

为了验证ZnO光催化剂对电厂烟气中NO的氧化效果,对初始浓度300 ppm的NO气体进行了紫外光下负载型ZnO光催化实验。研究所采用的纳米ZnO光催化材料由水热合成法制备,并与商业ZnO的效果进行了对比。用SEM和XRD对其进行了表征。实验结果表明,特定条件下,NO的氧化率达到14%,说明ZnO应用到气相光催化时还需要一定改进。     

纳米球状氧化锌的制备及光催化性能研究

在不添加表面活性剂条件下,用水热法合成制备出球状ZnO颗粒.利用X射线衍射(XRD)、电镜扫描(SEM)、紫外-可见漫反射光谱(UV-vis)等手段对产物进行表征,并根据实验结果提出可能的生长机理,并将制备的ZnO在紫外光照射下光催化降解30 mg/L的偏二甲肼(UDMH)废水.实验结果表明:制备的球状ZnO属于纳米级...     

低密度聚乙烯/氧化锌复合材料制备及其隔声性能研究

采用钛酸酯偶联剂对氧化锌（ZnO）进行表面改性,改性ZnO与低密度聚乙烯（LDPE）制备LDPE/ZnO复合材料。分析ZnO形貌及添加量对复合材料力学性能、阻尼性能、隔声性能及热稳定性的影响。结果表明：改性ZnO与LDPE具有良好的界面相容性,ZnO可以提升LDPE/ZnO复合材料的抗拉强度、隔声性能及热稳定性,四针状氧化锌（T-ZnO）添加量为5%时,复合材料的力学性能最好,综合性能最优。     

Growth of Copper on Single Crystalline ZnO: Surface Study of a Model Catalyst

Copper, vapor-deposited on the polar, Zn-terminated ZnO(0001) surface is investigated in view of its suitability as model system for the technologically important Cu/ZnO catalyst. The structure and electronic properties of Cu clusters on ZnO(0001)–Zn have been studied with scanning tunneling microscopy (STM), low energy electron diffraction (LEED), ultraviolet photoelectron spectroscopy (UPS), and low-energy He⁺ ion scattering (LEIS). At room temperature copper grows as two-dimensional (2D) clusters only at very low coverages of 0.001–0.05 equivalent monolayers (ML). At coverages greater than 0.01 ML, 3D clusters start to develop. This is contrasted to Cu growth on the oxygen-terminated ZnO(0001bar) surface, where a strong adhesion between Cu and the ZnO substrate results in an initial wetting of the surface by Cu. On ZnO(0001)–Zn, surface roughness and sputter damage change the growth mode to more 2D-like. Annealing in UHV results in well-separated, hexagonal clusters rotationally aligned with the substrate. Annealing of 2–5 ML Cu deposits on the ZnO(0001)–Zn surface in 10⁻⁶ mbar O₂ results in the formation of a (√3 × √3)R30° superstructure with respect to the ZnO lattice. This superstructure likely contains Cu⁺ sites. The suitability of the different surface morphologies to probe specific sites that are thought to be active for catalytic processes is discussed.     

Optical Properties of GaSb Nanofibers

Amorphous GaSb nanofibers were obtained by ion beam irradiation of bulk GaSb single-crystal wafers, resulting in fibers with diameters of ~20 nm. The Raman spectra and photoluminescence (PL) of the ion irradiation-induced nanofibers before and after annealing were studied. Results show that the Raman intensity of the GaSb LO phonon mode decreased after ion beam irradiation as a result of the formation of the amorphous nanofibers. A new mode is observed at ~155 cm^-1 both from the unannealed and annealed GaSb nanofiber samples related to the A_1g mode of Sb–Sb bond vibration. Room temperature PL measurements of the annealed nanofibers present a wide feature band at ~1.4–1.6 eV. The room temperature PL properties of the irradiated samples presents a large blue shift compared to bulk GaSb. Annealed nanofibers and annealed nanofibers with Au nanodots present two different PL peaks (400 and 540 nm), both of which may originate from Ga or O vacancies in GaO. The enhanced PL and new band characteristics in nanostructured GaSb suggest that the nanostructured fibers may have unique applications in optoelectronic devices.     

PVA／MC纳米纤维膜的制备与吸水性、保水性研究

采用水热工艺和电纺方法制备了PVA／MC纳米纤维膜;对PVA／MC混和溶液的粘度、PVA／MC纳米纤维膜的结构、吸水性能和保水性能进行了研究。结果表明,随着MC含量的增加,PVA／MC混和溶液的粘度逐渐增大;FESEM表明,本身不能电纺的MC在与PVA混和则可以电纺制得PVA／MC纳米纤维膜,但随着MC含量的增加,混和溶液的粘度会逐渐增大而无法电纺;在不改变电压的情况下增大电纺的接受距离,所得PVA／MC纤维膜连续、直径均匀、表面光滑平整;吸水性能和保水性能研究表明,随着MC含量的增加,PVA／MC纳米纤维膜的吸水速率和保水性能逐渐提高。     

Crystalline Gaq3 Nanostructures: Preparation, Thermal Property and Spectroscopy Characterization

Crystalline Gaq₃ 1-D nanostructures and nanospheres could be fabricated by thermal evaporation under cold trap. The influences of the key process parameters on formation of the nanostructures were also investigated. It has been demonstrated that the morphology and dimension of the nanostructures were mainly controlled by working temperature and working pressure. One-dimensional nanostructures were fabricated at a lower working temperature, whereas nanospheres were formed at a higher working temperature. Larger nanospheres could be obtained when a higher working pressure was applied. The XRD, FTIR, and NMR analyses evidenced that the nanostructures mainly consisted of δ-phase Gaq₃. Their DSC trace revealed two small exothermic peaks in addition to the melting endotherm. The one in lower temperature region was ascribed to a transition from δ to β phase, while another in higher temperature region could be identified as a transition from β to δ phase. All the crystalline nanostructures show similar PL spectra due to absence of quantum confinement effect. They also exhibited a spectral blue shift because of a looser interligand spacing and reduced orbital overlap in their δ-phase molecular structures.     

油酸修饰氧化锌纳米微粒的制备、表征和性能

采用水热法直接制备了油酸修饰的纳米氧化锌微粒.用XRD、SEM、IR和UV-Vis等检测手段对样品进行表征.结果表明:所制备的样品为纤锌矿结构的氧化锌微粒,平均粒度为44 nm;油酸分子与锌原子以桥连的形式结合;氧化锌微粒有明显的量子尺寸效应.分散性实验表明:样品在非极性的有机溶剂中有良好的分散性.     

The Modulation of Optical Property and its Correlation with Microstructures of ZnO Nanowires

ZnO nanowires with both good crystallinity and oxygen vacancies defects were synthesized by thermal oxidation of Zn substrate pretreated in concentrated sulfuric acid under the air atmosphere, Ar- and air-mixed gas stream. The photoluminescence spectra reveal that only near-band-edge (NBE) emission peak was observed for the sample grown in the air atmosphere; the broad blue–green and the red-shifted NBE emission peaks were observed for the sample grown in the mixed gas stream, indicating that the sample grown in the mixed gas stream has a defective structure and its optical properties can be modulated by controlling its structure. The high-resolution transmission electron microscope and the corresponding structural simulation confirm that the oxygen vacancies exist in the crystal of the nanowires grown in the mixed gas stream. The ZnO nanowires with oxygen vacancies defects exhibit better photocatalytic activity than the nanowires with good crystallinity. The photocatalytic process obeys the rules of first-order kinetic reaction, and the rate constants were calculated.     

带有12条柔性长链的卟啉及其金属配合物的合成及液晶性质的研究

以简单化合物为原料,经过多步反应合成出一种新型的、带有12条肉豆蔻酰氧基取代柔性长链的卟啉配体,并通过与过渡金属盐反应,得到卟啉金属锌、铜配合物。所合成的化合物经红外光谱、紫外-可见吸收光谱、~1HNMR等进行表征。通过荧光发射光谱、荧光寿命等进行了光学性质研究,并通过差示扫描量热法和偏光显微镜研究了化合物的液晶性质。结果表明,卟啉配体与铜配合物是双变液晶,而锌配合物在升温时呈现液晶相。化合物液晶相的相变温度较低,相变区间较窄。     

沉淀法制备花状ZnO粉体及性能研究

以二水合乙酸锌提供锌源,氨水调节pH值,聚乙二醇-2000为改性剂,采用沉淀法在一定的工艺条件下得到了花状ZnO粉体。并以SEM、TEM及XRD等测试手段对产物的形貌及结构方面进行了表征。利用X射线衍射仪进行结晶结构分析,表明花状ZnO为六方纤锌矿结构;利用场发射电子扫描电镜进行样品形貌分析,表明花状结构ZnO是由纺锤状棒状结构组成,棒的长径比为2．10;利用场发射透射电镜进行结晶结构分析,表明花状ZnO是单晶与多晶的混合体,室温光致发光谱表明花状ZnO在380nm左右存在紫外发射峰。     

沉淀法制备花状ZnO粉体及性能研究

以二水合乙酸锌提供锌源,氨水调节pH值,聚乙二醇-2000为改性剂,采用沉淀法在一定的工艺条件下得到了花状ZnO粉体。并以SEM、TEM及XRD等测试手段对产物的形貌及结构方面进行了表征。利用X射线衍射仪进行结晶结构分析,表明花状ZnO为六方纤锌矿结构;利用场发射电子扫描电镜进行样品形貌分析,表明花状结构ZnO是由纺锤状棒状结构组成,棒的长径比为2．10;利用场发射透射电镜进行结晶结构分析,表明花状ZnO是单晶与多晶的混合体,室温光致发光谱表明花状ZnO在380nm左右存在紫外发射峰。     

Growth of Nanograins in Electrospun ZnO Nanofibers

ZnO nanofibers were synthesized using an electrospinning method with polyvinyl alcohol and zinc acetate as precursor materials. The effects of the processing parameters on the microstructure of the synthesized ZnO nanofibers were investigated. X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy showed that the ZnO nanofibers were distributed uniformly over the Si substrates and had a polycrystalline nature. Individual nanofibers consisted of nanograins. Interestingly, the nanograins coalesced and grew under higher calcination temperatures and longer calcination times. The activation energy for grain-growth was estimated to be 13.126 kJ/mol, and the dominant growth mechanism was most likely to be related to lattice diffusion in pore control mode.     

ZnO量子点/硅橡胶复合材料的制备及光学性能研究

采用乙烯基乙烯基三乙氧基硅烷(A151)对ZnO量子点进行改性并制备成ZnO-A量子点,将ZnO-A量子点加入硅橡胶中制备得到ZnO-A/硅橡胶(S)纳米复合材料。采用红外及透射电镜(TEM)对ZnO-A进行性能分析,并通过TEM对复合材料的界面性能进行研究,最终研究了纳米复合材料的紫外-可见光透过率、荧光性能及介电常数。结果表明A151改性能有利于量子点在硅橡胶中的分散,增强了量子点与硅橡胶之间的相容性,该方法改善了纳米复合材料的可见光透过率及荧光性能。