ZnO Nanorods via Spray Deposition of Solutions Containing Zinc Chloride and Thiocarbamide

In this work we present the results on formation of ZnO nanorods prepared by spray of aqueous solutions containing ZnCl₂ and thiocarbamide (tu) at different molar ratios. It has been observed that addition of thiocarbamide into the spray solution has great impact on the size, shape and phase composition of the ZnO crystals. Obtained layers were characterized by scanning electron microscopy (SEM) equipped with energy selected backscattered electron detection system (ESB), X-ray diffraction (XRD) and photoluminescence spectroscopy (PL). Small addition of thiocarbamide into ZnCl₂ solution (ZnCl₂:tu = 1:0.25) supports development of significantly thinner ZnO nanorods with higher aspect ratio compared to those obtained from ZnCl₂ solution. Diameter of ZnO rods decreases from 270 to 100 nm and aspect ratio increases from ∼2.5 to 12 spraying ZnCl₂ and ZnCl₂:tu solutions, respectively. According to XRD, well crystallized (002) orientated pure wurtzite ZnO crystals have been formed. However, tiny ‘spot’—like formations of ZnS were detected on the side planes of hexagonal rods prepared from the thiocarbamide containing solutions. Being adsorbed on the side facets of the crystals ZnS inhibits width growth and promotes longitudinal c-axis growth.     

溶剂热法合成氧化锌纳米棒

采用PEG辅助溶剂热合成了ZnO纳米棒,通过SEM、EDS和XRD等手段对产物进行了表征。结果显示,合成的ZnO纳米棒直径在20 nm左右,长大约150,且长度和直径分布均匀。研究了PEG的添加量对形成ZnO纳米棒的影响,并且探讨了PEG促进纳米棒生长的机理。     

ZnO纳米棒水热法生长与表征

采用两步法在FTO导电玻璃衬底上制备ZnO纳米棒,首先利用浸渍-提拉法在FTO导电玻璃衬底上制备ZnO晶种层,然后把有ZnO晶种层的FTO衬底放入盛有生长溶液的反应釜中利用水热法制备ZnO纳米棒.研究了生长溶液的浓度、生长温度和生长时间对所制备的对ZnO纳米棒阵列的微结构和光致发光性能的影响,利用X射线衍射(XRD)、扫描电子显微镜(SEM)和光致发光谱(PL)研究了ZnO样品的结构、形貌和光学性质.实验结果表明:所制备的ZnO纳米棒呈现六方纤锌矿结构,沿(002)晶面择优取向生长,纳米棒的平均直径约为100 nm,长度约为2.5 μm.所制备的ZnO纳米棒在390 nm附近具有很强的紫外发光峰和在550 nm附近有较弱的宽绿光发光峰.     

以氨化碱式氯化锌为前驱体制备花状多孔氧化锌

用化学沉淀法结合后续的煅烧工艺制备了三维花状多孔氧化锌.用XRD、FE-SEM、TG-DTA和BET对产物进行分析.沉淀法制得的前驱体为花状氨化碱式氯化锌(Zn5(OH)8Cl2·xH2O·yNH3,记为ZHC-NH3),ZHC-NH3是氨分子插入到碱式氯化锌(Zn5(OH)8Cl2·H2O,记为ZHC)层状结构的层间所得的产物.通过水浴加热可以除去层间氨分子,得到ZHC纯相.ZHC-NH3前驱体花状结构的直径在80～ 150 μm之间,是由很多互相穿插的纳米片组成,纳米片的厚度为～ 100 nm,直径为～20 μm.ZHC-NH3经过煅烧,释放出H2O、NH3和HCl等挥发性气体,得到多孔的氧化锌.这些多孔氧化锌良好继承了ZHC-NH3前驱体的花状形貌.本文提出了ZHC-NH3向ZnO转变的可能的分解机制,也讨论了花状ZHC-NH3前驱体的合理的生长机理.     

氧化锌纳米棒及纳米管阵列薄膜的制备

采用水溶液法在ITO玻璃上电沉积了高度取向的ZnO纳米棒阵列,并通过碱液化学浸蚀法获得了ZnO纳米管.分别探讨温度及沉积时间对ZnO纳米棒阵列薄膜沉积的影响,和温度及浸蚀时间对浸蚀ZnO纳米管阵列薄膜的影响,采用SEM测试方法分析了ZnO纳米管阵列薄膜的最终形态.     

含氯离子电解液中阳极氧化制备超细氧化锌

采用阳极氧化法在纯水、水溶液、水与有机物混合液、有机溶液和纯有机物不同电解液中制备超细氧化锌,并用SEM、EDS、XRD对其形貌、元素、晶型进行分析表征。在水溶液中形成的氧化锌宽度0.8μm,长度6μm。水和无水乙醇的混合溶液中形成的氧化锌宽度0.7μm,长度9μm,且无团聚现象。XRD图表明直接生成的产物为无定形结构,在325℃焙烧4 h后全部转化为六方晶形纤锌矿结构的氧化锌,且纯度和结晶度都很高。     

碱式氯化镁纳米棒的制备和表征

以六水氯化镁和轻质氧化镁为原料,采用液相法制备出直径约100nm,长径比大于100的碱式氯化镁单晶纳米棒。通过X射线衍射(XRD)、扫描电子显微镜(SEM)和选区电子衍射(SAED)对产物进行了分析与表征,考察了氯化镁溶液的初始浓度、氧化镁与氯化镁的物质的量比、反应温度、陈化时间、陈化温度和溶剂等物质的量参数对产品形貌的影响,得到的最佳工艺条件为:氯化镁溶液的初始浓度为4mol/L,氧化镁与氯化镁的物质的量比为0.07,反应温度为50℃,陈化时间为48h,陈化温度为20℃,乙醇与水的混合溶液(溶剂)的体积比为2.5:1。     

Facile Synthesis of ZnO Nanorods by Microwave Irradiation of Zinc–Hydrazine Hydrate Complex

ZnO nanorods have been successfully synthesized by a simple microwave-assisted solution phase approach. Hydrazine hydrate has been used as a mineralizer instead of sodium hydroxide. XRD and FESEM have been used to characterize the product. The FESEM images show that the diameter of the nanorods fall in the range of about 25–75 nm and length in the range of 500–1,500 nm with an aspect ratio of about 20–50. UV–VIS and photoluminescence spectra of the nanorods in solution have been taken to study their optical properties. A mechanism for microwave synthesis of the ZnO nanorods using hydrazine hydrate precursor has also been proposed.     

水热法制备纳米棒状氧化锌及其性能表征

以硝酸锌和氢氧化钠为原料、十二烷基三甲基氯化铵为分散剂,采用温和水热法在100℃条件下,制备了纳米棒状氧化锌.通过XRD物相分析可知,合成ZnO纳米粒子的物相均是六方晶系纤锌矿结构;TEM形貌观察,粒子基本为棒状,纳米棒状ZnO的平均直径约为30～40 nm、长度约60～70 nm.水溶液中次甲基蓝染料在棒状纳米ZnO光催化下、pH为8.0时,能迅速分解,在降解90 min时,次甲基蓝的降解率达到100%.     

ZnO纳米棒的制备及其光催化活性研究

以Zn(Ac)2·2H2O、NaI和N2H4·H2O为原料,在未使用任何表面活性剂的简单水热反应体系中制得了ZnO纳米棒.采用X射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)对产物的晶体结构、形貌进行了表征分析,并对其光催化活性进行了探讨,以ZnO纳米棒为光催化剂对有机染料污染物甲基橙进行了光催化降解实验.实验结果表明,氧化锌纳米棒对甲基橙的光催化降解具有很好的催化作用,在紫外光照射120min后,对甲基橙的降解率接近完全.     

Solution combustion synthesis of ZnO powders using CTAB as fuel

Zinc oxide (ZnO) powders have been prepared by solution combustion synthesis method using cetyltrimethylammonium bromide (CTAB) as fuel. The effects of fuel to oxidant ratios (? = 0.5, 0.75, 1 and 1.5) on the combustion behavior, phase evolution, microstructure, optical properties and photocatalytic performance were investigated by thermal analysis, X-ray diffractometry, electron microscopy, and diffuse reflectance spectrometry techniques. The slow decomposition rate of CTAB guaranteed the direct formation of single phase and well-crystalline ZnO powders regardless of fuel content. The specific surface area of the as-combusted ZnO powders with platelet particles increased from 21 ± 1 to 35 ± 2?m²/g with fuel content. The band gap energy also increased from 2.99 to 3.13?eV due to the decrease of particle size. The as-combusted ZnO powders at ? = 1.5 exhibited the highest photodegradation (~69%) of methylene blue under ultraviolet light irradiation, due to their good crystallinity and smaller particle size.     

Solution combustion synthesis of ZnO powders using mixture of fuels in closed system

Single phase ZnO powders with wurtzite structure were synthesized by solution combustion method using various amounts of mixed glycine-citric acid fuel in the presence (open system) and absence (closed system) of air oxygen. Phase evolution, microstructure and optical properties were investigated by thermal analysis, X-ray diffractometry, electron microscopy and Raman, photoluminescence (PL) and diffuse reflectance spectrometry techniques. Rapid combustion reaction in closed system led to weak crystallinity, as confirmed by deep-level emissions in PL spectra. Larger spherical particles (~200?nm) were synthesized in open system at ? =?1. The as-combusted ZnO powders in closed system exhibited higher photocatalytic activity under ultraviolet irradiation, due to their higher adsorption capacity of methylene blue on ZnO surface. Photodegradation rate increased with the increase of fuel content in as-combusted ZnO powders produced by open route as a result of the reduction of particle size and band gap energy.     

氯化钙废液生产复合磷酸锌防锈颜料新工艺

以氯化钙废液为原料,生产低成本高效的复合磷酸锌防锈颜料,是一项变废为宝的环保型新工艺,具有广阔的市场前景和社会效益。     

氯化锌催化合成二异亚丙基-D-甘露醇

以甘露醇为原料,氯化锌作催化剂合成二异亚丙基-D-甘露醇,考察了影响反应的因素,结果表明反应的最佳条件为:n(D-甘露醇)∶n(丙酮)∶n(氯化锌)=1∶21·4∶1·85,反应温度为30~35℃,反应时间12h,产率可达62·8%。     

Role of Seed Layer Crystalline Quality in Photoresponse Performance of Hydrothermally Grown ZnO Nanorods

We investigated the effects of the crystalline state for seed layers (SLs) on the growth morphology and material characteristics for hydrothermally grown ZnO nanorods (NRs). For this, preheating (PH) at different temperatures (100–300 °C) and O₂ plasma treatment (PT) for 9 min were performed during the growth of SLs on p-Si by the aqueous solution-based method to provide the characteristic change on the NR growth platform. An improvement in material properties was achieved from the ZnO NRs grown on the SL crystals of enhanced crystalline quality in terms of the increased preferred orientation (002), the higher UV emission with suppressed deep-level emissions, the recovery of O/Zn stoichiometry, and the reduction of various intrinsic defects. Ultraviolet photodiodes of a p-Si/n-ZnO-NR structure fabricated under the SL conditions of O₂ PT and PH at 100 °C showed a significantly enhanced on-off current ratio of ~90 at +5 V and faster photoresponse characteristics presenting a reduction in the fall time from 16 to 9 s.     

Synthesis of well-aligned ZnO nanorod arrays from mixed sulfide-oxide lead and zinc ore

A novel process of recovery of zinc from mixed sulfide-oxide lead and zinc ore was presented in this paper. ZnO nanorod arrays (ZNRAs) on FTO substrate pre-coated with a layer of ZnO seeds was synthesized successfully from the mixed ore via the oxidative ammoniacal leaching process and a two-step process including precipitation and hydrothermal synthesis. The characterization results from the XRD, SEM and UV–vis spectrophotometer analysis showed that the as-prepared ZNRAs was well-aligned, large-scale, perpendicular to the FTO substrate and had a reduced band gap energy of 3.03 eV. XPS analysis indicated that the grown ZNRAs were doped by a small quantity of carbon and did not contain any other impurities particularly Fe and Pb. The total zinc extraction can reach 92.4% after the oxidative ammoniacal leaching process and the precipitation process. The elimination of conventional purification process in zinc production was achieved due to the efficient and selective oxidative ammoniacal leaching process.     

纳米ZnO的制备及其光催化降解酸性红B

以Zn（acac）2·H2O为单源前驱体,用水热法成功地制备了纳米ZnO,利用X-射线衍射、扫描电子显微镜、透射电子显微镜等手段对样品进行了表征。对自制的纳米ZnO进行了光催化活性研究,结果表明：纳米ZnO对200～380nm波长范围的光和在可见光范围内都有较强的吸收作用。利用纳米ZnO作为光催化剂对有机染料溶液进行了降解实验,发现在太阳光照射3h后,对酸性红B的降解率可达到100%。     

熔融法合成甘氨酸锌配合物及表征

以甘氨酸和乙酸锌为原料,采用熔融法合成了甘氨酸锌配合物,其合成的最佳工艺条件为：原料摩尔比n甘氨酸：n乙酸锌=2：1,在刚好熔融状态下,即反应温度大约在125℃左右,反应时间0.5h.所得产品的产率达99%.并通过元素分析,红外光谱,X-射线粉末衍射,差热-热重等实验手段对该配合物的结构和成份进行了表征,确定其主要组成为Zn（NH2CH2COO）2.     

Synthesis of multi-shelled ZnO hollow microspheres and their improved photocatalytic activity

Herein, we report an effective, facile, and low-cost route for preparing ZnO hollow microspheres with a controlled number of shells composed of small ZnO nanoparticles. The formation mechanism of multiple-shelled structures was investigated in detail. The number of shells is manipulated by using different diameters of carbonaceous microspheres. The products were characterized by X-ray powder diffraction, scanning electron microscopy, and transmission electron microscopy. The as-prepared ZnO hollow microspheres and ZnO nanoparticles were then used to study the degradation of methyl orange (MO) dye under ultraviolet (UV) light irradiation, and the triple-shelled ZnO hollow microspheres exhibit the best photocatalytic activity. This work is helpful to develop ZnO-based photocatalysts with high photocatalytic performance in addressing environmental protection issues, and it is also anticipated to other multiple-shelled metal oxide hollow microsphere structures.     

One-step synthesis of ZnO and Ag/ZnO heterostructures and their photocatalytic activity

By following a one-step, novel methodology, ZnO and Ag/ZnO heterostructures were successfully synthesized at room-temperature. This route is simple, effective, high yield (91%), environmentally friendly (green synthesis) and consists of a mechanically assisted metathesis reaction. The metathesis reaction used in this investigation showed two results: the in-situ generation of alkaline nitrates, LiNO₃/NaNO₃, and the direct crystallization of the desired Zn-based compounds in milling media; revealing a true mechanochemical synthesis of ZnO and Ag/ZnO (1.25, 2.50 and 4.50 mol% of Ag) heterostructures. Particles showed spherical-like morphologies and sizes smaller than 20 nm. The Ag/ZnO heterostructures exhibited higher photocatalytic activity than ZnO for degrading methylene blue (MB) dye. It was also shown that the presence of Ag (up to 1.25 mol%) nanoparticles (NPs) in ZnO accelerates the photodegradation reaction and then slows down with further increases in Ag contents. The 1.25-Ag/ZnO sample (10 mg) showed the highest photocatalytic activity (96%) for degrading MB (100 ml, 10 mg L^?1) within 100 min under UV–Vis light irradiation (λ = 310 nm).