多级结构氧化锌的构筑、形貌调控及其光催化活性

分别以混合常见二锌盐为锌源, 以离子液体和柠檬酸钠为表面活性剂, 在绿色温和的条件下采用二次沉积法制备出多级结构氧化锌。用XRD、IR、SEM、UV-Vis、PL等表征了样品的组成、结构、形貌、光致发光性能及光催化性能。探讨了表面活性剂、阴离子、温度等因素对氧化锌形貌的影响。结果表明, 由不同表面活性剂所得到样品的多级结构有较大的差异。此外, 推测了在多级结构氧化锌形成过程中, 阴离子和温度对样品形貌的调控作用, 并对比了三种典型样品的光催化性能, 其中样品-1的光催化性能最好。     

多级结构氧化锌的构筑、形貌调控及其光催化活性

分别以混合常见二锌盐为锌源,以离子液体和柠檬酸钠为表面活性剂,在绿色温和的条件下采用二次沉积法制备出多级结构氧化锌。用XRD、IR、SEM、UV-Vis、PL等表征了样品的组成、结构、形貌、光致发光性能及光催化性能。探讨了表面活性剂、阴离子、温度等因素对氧化锌形貌的影响。结果表明,由不同表面活性剂所得到样品的多级结构有较大的差异。此外,推测了在多级结构氧化锌形成过程中,阴离子和温度对样品形貌的调控作用,并对比了三种典型样品的光催化性能,其中样品-1的光催化性能最好。     

低共熔溶剂中纳米氧化锌的制备及形貌调控

分别以工业氧化锌、氯化锌和草酸锌为锌源,氯化胆碱-尿素低共熔溶剂为溶剂,通过沉淀法制备了不同结构和形貌的纳米氧化锌。通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)和甲基橙光催化降解对样品进行了表征,分析了锌源变化对产物形貌的影响以及不同形貌氧化锌形成过程中前驱体的调控作用及反应机理。并将制备的不同形貌氧化锌应用于光催化降解甲基橙。结果表明制备的由纳米晶组装而成的厚块状Zn O纳米结构对甲基橙有良好的光催化性能。     

表面活性剂种类对纳米氧化锌形貌的影响

利用简单的水热法,以Zn(Ac)2.2H2O为锌源,通过调整表面活性剂的种类及碱源,制备了一系列不同形貌的纳米结构氧化锌;利用场发射扫描电子显微镜和X射线粉末衍射仪分析了产物的形貌和晶体结构,并探讨了多种表面活性剂和醋酸钠碱源对氧化锌纳米结构的影响.结果表明,以NaOH作为碱源时,在不添加任何表面活性剂的情况下,产物的形貌结构与氢氧化钠的加入量有关,当n(Zn2+)∶n(OH-)为1∶2.5、1∶10及1∶20时,分别得到片状、棒状及海胆状纳米结构的氧化锌;产物均为六方相氧化锌.     

生物模板法制备纳米氧化锌及其表征

本文以油菜花粉为生物模板,硝酸锌为锌源制备了一种分级多孔结构的纳米氧化锌。采用SEM、TEM、XRD和 FTIR等技术手段对其进行了表征。实验结果表明,采用油菜花粉为生物模板制备的氧化锌纳米材料为六方纤锌矿结构,较好的复制了花粉的分级多孔结构。同时,研究了制备条件诸如煅烧温度和反应物浓度对产物结构、形貌和尺度的影响。     

生物模板法制备纳米氧化锌

本文以油菜花粉为生物模板、硝酸锌为锌源制备了一种分级多孔结构的纳米氧化锌。采用SEM、TEM、XRD和FTIR等技术手段对其进行了表征。实验结果表明,采用油菜花粉为生物模板制备的氧化锌纳米材料为六方纤锌矿结构,较好地复制了花粉的分级多孔结构。同时,研究了制备条件诸如煅烧温度和反应物浓度对产物结构、形貌和尺度的影响。     

类胆碱离子液体中多级结构Bi_2S_3的形貌调控合成

本文通过简单温和的溶液合成方法,在类胆碱离子液体体系中制备了纳米线簇、绒球状、海胆状和纳米花状等不同形貌可控的Bi_2S_3纳米材料.通过X射线粉末衍射(XRD)、扫描电子显微镜(SEM)和电子透射电镜(TEM)对样品的形貌与结构进行了分析表征.实验结果表明,IL/H_2O/PEG-200的比例在调控不同形貌的Bi_2S_3形成过程中起到了决定性的作用.同时也研究了离子液体阳离子烷基侧链的长度和反应时间对样品形貌形成过程的影响.基于晶体分裂和溶解-重结晶过程对不同形貌Bi_2S_3样品的形成机理进行了分析讨论.     

以离子液体为铝源和模板合成氧化铝纳米纤维

以咪唑类氯铝酸盐离子液体(x Al Cl_3-[C_(10)mim]Cl)为模板和铝源,采用溶胶-凝胶法合成了氧化铝纳米纤维.考察了氯铝酸盐离子液体中Al Cl_3的摩尔分数以及焙烧温度对纤维状氧化铝合成的影响,通过X射线衍射仪(XRD)、场发射透射电子显微镜(TEM)和物理吸附仪对样品进行了表征.研究结果表明,氯铝酸盐离子液体可以同时作为模板剂和铝源合成具有一定形貌的氧化铝.当Al Cl_3的摩尔分数x(Al Cl_3)=0.5时,可以合成出纳米纤维状氧化铝,纳米纤维直径约为2 nm,长度约为200 nm,比表面积为238.38 m~2/g,孔容为0.54 cm~3/g,平均孔径为8.43 nm.合成的氧化铝具有高的热稳定性,在900℃下焙烧依然能够很好地保持其形貌结构和γ晶型.此外,提出了氢键共π-π键堆积机理来解释超细纤维氧化铝的合成过程.     

氧化锌/镁铝复合氧化物的制备及光催化性能

将镁铝层状双氢氧化物分散在锌盐与尿素的混合液中,加热使尿素水解、锌离子沉淀,经洗涤、干燥、煅烧,再用碳酸钠溶液浸渍、煅烧,得到还原后的氧化锌/镁铝复合氧化物。用X-射线衍射(XRD)、透射电子显微镜(TEM)、氮等温吸附和傅里叶红外光谱(FTIR)等方法对所制备的氧化锌/镁铝复合氧化物的结构和性能进行了表征。以酸性红G为模型污染物评价了其去除效率及光催化活性。碳酸钠还原处理过的氧化锌/镁铝复合氧化物结构发生了改变,氧化锌的晶粒变小,复合氧化物变成了片状结构,其对酸性红G的去除效率也明显提高,质量比为2∶1的氧化锌/镁铝复合物经还原后表现出了良好的光催化活性。     

电化学法沉积氧化锌晶须

应用阳极氧化法沉积氧化锌(ZnO)松针状晶须,SEM和XRD观察、表征样品形貌与结构.结果表明,电沉积氧化锌晶须直径为20～50 nm、长度200～300 nm、长径比10～15,纯度高,结晶度好,属六方晶系纤锌矿(JCPDS 36-1451).循环伏安法研究了该氧化锌结晶过程,并考察了电解液的锌酸盐[Zn(OH)4]2-浓度和基底表面氧化膜对晶须生成的影响.     

咪唑类离子液体辅助水热法合成棒状微/纳米ZnO晶体

以醋酸锌和氢氧化钠为原料, 以水和含不同长度烷基链的咪唑类氯盐离子液体的混合物作为反应介质, 采用水热法合成出不同形貌的微/纳米ZnO晶体, 用扫描电子显微镜(SEM)和X射线衍射仪(XRD)对合成的ZnO晶体进行表征. 研究了烷基链长度、 离子液体用量、 反应时间以及反应温度对形成棒状ZnO晶体形貌的影响. 实验结果表明, 所制备的棒状ZnO晶体样品均为六方晶系结构. 在棒状ZnO晶体的制备过程中, 控制反应温度, 选择不同的离子液体及其用量十分重要.     

Metastable solid solutions in the system ZnOCoO: synthesis by hydrolysis in polyol medium and study of the morphological characteristics

Metastable solid solutions in the system ZnOCoO have been synthesized by hydrolysis of ionic zinc and/or cobalt salts in polyol medium. The solubility of Co in the zincite oxide was significantly increased (at.% Co=65) compared to that obtained under thermodynamical equilibrium (at.% Co=6.5 at 800°C). CoO was also obtained via this route. The products are made up of sub-micrometer particles. A detailed study of their morphology along with pure ZnO particle morphology was conducted. Different growth mechanisms are evidenced.     

不同形貌纳米氧化锌的水热法合成

以氯化锌为锌源,以氢氧化钠为碱源,采用水热法合成了不同形貌的纳米氧化锌;探讨了晶化时间、晶化温度、表面活性剂十六烷基三甲基溴化铵(CTAB)对纳米ZnO形貌的影响.结果表明:不添加CTAB时,在120℃下反应24h得到的纳米氧化锌为颗粒状,而在160℃下反应24h得到的纳米氧化锌为片状.当添加CTAB后,在120℃可得到片状氧化锌,而在160℃可得到颗粒状氧化锌.     

Synthesis and optical properties of ZnO nanostructures in imidazolium-based ionic liquids

Different morphologies of ZnO nanostructures have been synthesized by a simple reflux method, in imidazolium-based ionic liquids and water as a solvent. The effects of ionic liquid as a template with different concentrations and the amount of sodium hydroxide on the morphology and size of nanostructures were investigated. The structural and optical properties of these ZnO particles were studied by using XRD, SEM and UV–Visible. The characteristic results revealed that using different ionic liquids in water not only prevent a drastic increase in the crystallite size of the zinc oxide species but also provide suitable conditions for the oriented growth of primary nanoparticles with nano sheet and nano hallow block. The results show that the longer alkyl chain at position-1 of imidazole ring or using dicationic ionic liquid with a definite concentration cause the more width of nano sheet. A possible mechanism was proposed to explain the formation of ZnO nanostructures with different morphology.     

Ultraviolet emission of ZnO nano-polycrystalline films by modified successive ionic layer adsorption and reaction technique

Zinc oxide (ZnO) nano-polycrystalline films were successfully prepared by modified successive ionic layer adsorption and reaction at room temperature technique which was based on the alternate immersion of substrate in the alkaline zinc precursor and deionized water. ZnO films were formed through accumulation of ZnO crystal clusters. The synthesis, microstructure, and optical properties of ZnO nano-polycrystalline films were investigated. Prepared ZnO films exhibited wurtzite structure, with good surface morphology and optical properties. Ethanolamine was employed as a complex reagent, which improved the adsorption of zinc complex with substrate. Effects of technique parameters on the properties of ZnO nano-polycrystalline films were studied in detail. Some parameters, including cycle number of preparation, ratio of zinc to ethanolamine, pH value of precursor and zinc concentration, played key roles in the deposition of ZnO nano-polycrystalline films. Intensive and sharp ultraviolet emission peaks at about 400 nm could be observed in the photoluminescence spectra.     

Straight and thin ZnO nanorods: hectogram-scale synthesis at low temperature and cathodoluminescence

A novel seed-assisted chemical reaction at 95 degrees C has been employed to synthesize uniform, straight, thin, and single-crystalline ZnO nanorods on a hectogram scale. The molar ratio of ZnO seed and zinc source plays a critical role in the preparation of thin ZnO nanorods. At a low molar ratio of ZnO seed and zinc source, javelin-like ZnO nanorods consisting of thin ZnO nanorods with a diameter of 100 nm and thick ZnO nanorods with a diameter of 200 nm have been obtained. In contrast, straight ZnO nanorods with a diameter of about 20 nm have been prepared. Dispersants such as poly(vinyl alcohol) act spatial obstructors to control the length of ZnO nanorods. The morphology, structure, and optical property of the ZnO nanostructures prepared under different conditions have been characterized by transmission electron microscopy, field emission scanning electron microscopy, X-ray powder diffraction, high-resolution transmission electron microscopy, and cathodoluminescence. The formation mechanisms for the synthesized nanostructures with different morphologies have been phenomenologically presented.