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.     

微/纳米结构ZnO/TiO_2复合光催化剂的制备及其光催化性能研究

以微米尺寸的花状和棒状ZnO为载体,利用表面吸附层水解方法,制备了具有微/纳米结构的ZnO/TiO2复合光催化剂。采用SEM、XRD、EDS和UV对其形貌、结构、表面组成等进行了表征。结果表明,在棒状或花状微米尺寸ZnO表面能形成均一尺寸的TiO2纳米粒子。复合物中表面TiO2含量与Ti(OC4H9)4添加量呈正相关性。得到的复合物为纤锌矿型氧化锌和锐钛矿型氧化钛复合物。对不同组成ZnO/TiO2复合物的光催化活性进行了初步研究。     

氧化锌纳米棒/云母复合粉体的合成、表征及红外发射性能

采用液相沉积法制备了氧化锌(ZnO)纳米棒负载云母复合粉体,其合成工艺分为:(1)云母粉体表面沉积ZnO纳米粒子,并经煅烧制得表面晶种化的云母粉体;(2)以七水硫酸锌(ZnSO4·7H2O)为前驱体,乙醇胺和氨水为络合剂,制得液相沉积前驱体溶液,并在晶种化的云母粉体表面沉积ZnO纳米棒。利用X-射线衍射(XRD)、ζ电位仪、扫描电子显微镜(SEM)以及红外发射率测试仪对氧化锌/云母复合粉体进行了测试与表征。结果表明,云母分散于乙醇水体积比为1∶1的混合溶液中,其表面带负电(-37 mV),而ZnO粒子表面则带正电(16 mV);两种粒子混合时,可通过静电引力实现ZnO纳米粒子在云母表面沉积;随着云母表面ZnO纳米棒沉积密度的增大,复合粉体在8~14μm波段内的红外发射率逐渐增大,从0.800增加至0.863;对比棒状ZnO球体,结构单元聚集状态的变化对最终红外发射性能的影响不大。     

结晶紫在亚微米棒状ZnO表面增强拉曼光谱的研究

通过湿化学法在70℃低温条件下,制备了亚微米棒状ZnO。利用紫外可见吸收光谱(UV-Vis),扫描电镜(SEM),X射线粉末衍射(XRD)以及拉曼光谱对棒状ZnO进行了表征。采用密度泛函(DFT/B3LYP)方法,以6-311G*为基组研究了结晶紫(CV)的理论平衡构型,同时以CV作为探针分子,检测了亚微米棒状ZnO的表面增强拉曼(SERS)活性。结果表明:亚微米棒状ZnO为六方纤锌矿结构,具有很高纯度和结晶度。CV在ZnO表面的拉曼增强因子可达1.2×102,其增强机理主要来源于化学增强。     

氧化锌纳米棒/云母复合粉体的合成、表征及红外发射性能

采用液相沉积法制备了氧化锌(ZnO)纳米棒负载云母复合粉体,其合成工艺分为：(1)云母粉体表面沉积ZnO纳米粒子,并经煅烧制得表面晶种化的云母粉体;(2)以七水硫酸锌(ZnSO₄·7H₂O)为前驱体,乙醇胺和氨水为络合剂,制得液相沉积前驱体溶液,并在晶种化的云母粉体表面沉积ZnO纳米棒。利用X-射线衍射(XRD)、ζ电位仪、扫描电子显微镜(SEM)以及红外发射率测试仪对氧化锌/云母复合粉体进行了测试与表征。结果表明,云母分散于乙醇水体积比为1：1的混合溶液中,其表面带负电(-37mV),而ZnO粒子表面则带正电(16mV);两种粒子混合时,可通过静电引力实现ZnO纳米粒子在云母表面沉积;随着云母表面ZnO纳米棒沉积密度的增大,复合粉体在8~14μm波段内的红外发射率逐渐增大,从0.800增加至0.863;对比棒状ZnO球体,结构单元聚集状态的变化对最终红外发射性能的影响不大。     

BSA在不同形貌氧化锌材料上的吸附热力学

采用高分子模板法合成了4种不同形貌的ZnO,分别为球状颗粒(ZnO NPs)、针状(ZnO NRs)、片状(ZnO NSs)和棒状(ZnO NBs).利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和能谱仪(EDS)对产物进行了表征.通过傅里叶变换红外光谱仪(FTIR)和圆二色光谱仪(CD)研究了小牛血清白蛋白(BSA)在不同形貌ZnO上的等温吸附规律、吸附热力学和吸附作用机理.结果表明,4种不同形貌的ZnO对BSA的吸附均较好地符合Langmuir等温吸附模型;吸附量随温度的升高略有增加;从热力学参数(ΔG,ΔH,ΔS)可知,吸附反应为自发进行的吸热反应,作用机理主要为氢键和静电作用.从热力学角度,针状的ZnO更有利于BSA的吸附.     

室温一步固相反应合成纳米氧化锌的表征、光催化性能及动力学（英文）

以七水硫酸锌、氢氧化钠为原料,采用室温一步固相反应合成ZnO纳米粒子,并分别利用X射线衍射分析(XRD)、傅里叶变换红外光谱分析(FTIR)、热重分析(TG)、扫描电子显微分析(SEM)、透射电子显微分析(TEM)、N2吸附-脱附、紫外可见漫反射光谱分析(UV-Vis DRS)等方法对ZnO纳米粒子进行表征。实验结果表明:不需任何添加剂,室温下可通过一步固相反应合成ZnO纳米粒子,其形成过程首先是Zn SO4·7H_2O和NaOH充分接触,然后反应形成Zn4SO4(OH)6·5H_2O,最后NaOH的溶解热可使Zn4SO4(OH)6·5H_2O转变为ZnO并逐渐长大形成纳米粒子。同时以甲基橙为降解对象评价了ZnO纳米粒子的光催化活性,实验结果表明:紫外光照射下,该方法合成的ZnO纳米粒子对甲基橙具有较好的光催化活性,且光催化动力学方程符合准一级反应动力学。     

季铵化壳聚糖/纳米氧化锌杂化胶体粒子的制备及性能

以羟丙基三甲基氯化铵壳聚糖(QAC)和L-半胱氨酸(L-cys)为稳定剂制备羟丙基三甲基氯化铵壳聚糖/纳米氧化锌(QAC/ZnO)杂化胶体粒子。通过红外光谱、X射线衍射、X射线光电子能谱、热重分析对QAC/ZnO杂化胶体粒子的化学组成进行分析;用Zeta电位仪、纳米粒度仪、透射电镜对杂化胶体粒子的粒径及形貌进行了系统的表征;通过紫外、细胞实验等对杂化胶体粒子的紫外透光率、抗氧化性、光催化活性以及细胞毒性进行了表征。结果表明,QAC/ZnO杂化胶体粒子具有良好的紫外线屏蔽性和抗氧化性,且无细胞毒性,在防晒化妆品领域有一定的应用前景。     

一种纳米氧化锌复合生物基水性聚氨酯的合成和性能研究

以自制的生物基水性聚氨酯(APU)及纳米氧化锌(ZnO)为原料制备了APU/ZnO复合材料,并通过红外光谱(FT-IR)、热重(TG)、紫外(UV)、透射电镜(TEM)和扫描电镜(SEM)等手段对复合材料的性能进行了表征。TEM和SEM照片显示,制得的新型纳米ZnO的尺寸为200 nm左右,可较均匀地分散在APU体系中。TG测试结果表明添加了少量纳米ZnO的复合材料的耐热性有了明显提高。同时测试结果表明,少量纳米ZnO粒子的加入对APU有很好的增强和增韧效果,且具有一定的抗菌性和抗紫外性能。     

不同尺寸纳米氧化锌的制备及其抗菌性能研究

溶液化学方法在制备ZnO纳米材料时最为常用,通常情况下,可以采用水或其它有机溶剂作为反应介质,制备不同尺寸和形貌的ZnO纳米粒子。本文以油酸钠为表面活性剂,乙酸锌为前驱体,使用不同醇溶剂(乙醇、正丁醇、正己醇),通过控制反应温度,在较为温和的反应条件下,成功制备了不同尺寸的球形纳米ZnO粒子。使用透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)、X-射线衍射(XRD)和紫外-可见吸收光谱(UV-vis)等方法对所得到的ZnO纳米粒子进行了表征,在此基础上,选取其中五种不同尺寸的ZnO纳米粒子,使用平板浇注法,探究不同尺寸ZnO纳米粒子对大肠杆菌和金黄葡萄杆球菌的抗菌效果。结果表示:随着醇溶剂碳链长度和温度的增加,ZnO纳米粒子的尺寸会逐渐增加;随着ZnO纳米粒子的尺寸的减小,其抗菌效果逐渐增强。相比于金黄葡萄杆球菌,ZnO纳米粒子对大肠杆菌的抗菌效果较差。当ZnO纳米粒子的浓度为6×10^-3mol·L^-1时,对金黄葡萄杆球菌和大肠杆菌的抑菌率分别达到了96.6%和91.4%。     

Synthesis and UV shielding properties of zinc oxide ultrafine particles modified with silica and trimethyl siloxane

This paper introduces a kind of ZnO ultrafine particles modified with silica and trimethyl siloxane (TMS). Thus zinc carbonate hydroxide (ZCH) as the precursor of ZnO was synthesized using chemical precipitation method, and the precursor was modified in situ with silica and TMS. The modified ZnO ultrafine particles were obtained after calcinating the modified precursors. The surface properties of the modified ZnO ultrafine particles were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectra (XPS), scanning electron microscope (SEM), and transmission electron microscopy (TEM). The effects of the modifiers on the photocatalytic activity and UV shielding ability of ZnO ultrafine particles were also investigated and discussed.     

Physicochemical Interaction of ZnO Fine Particles with 5‐Mono‐(4‐carboxyphenyl)‐10,15,20‐Triphenylporphyrin

This study deals with an investigation on the preparation and physicochemical interactions of ZnO nanoparticles with acid functionalized porphyrin [5‐mono‐(4‐carboxyphenyl)‐10,15,20‐triphenylporphyrin (CPTPP)] for photovoltaic applications in a detailed manner. Zinc acetate and sodium hydroxide were used as the starting materials for the synthesis of ZnO nanoparticles at 60 °C in an alcoholic medium. The freshly prepared fine particles were then functionalized with CPTPP. Both the virgin and pregnant ZnO particles were characterized by using UV‐Visible spectrophotometry (UV), fluorescence emission (PL), Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD) and scanning electron microscopy (SEM). The band gap energy obtained for ZnO particles, having a value of 3.47 eV, shows significant quantum confinement effect and enhanced photophysical activity. FTIR analysis of the doped ZnO nanostructures showed the presences of some chemical species. SEM analysis revealed a clear change in the surface morphologies of undoped ZnO. The average crystallite size of nanoparticles, calculated from XRD peaks, was found in the nano regime. The lattice parameters calculated for ZnO nanocrystals were also found in good agreement with those given in the literature. From the enhancement in the red shift of the UV‐Vis spectra, it is concluded that hybridization of acid functionalized porphyrin can cause a significant expansion in the total absorption region of ZnO semiconductor for photovoltaic applications.     

Synthesis of ZnO/polystyrene composites particles by Pickering emulsion polymerization

ZnO/polystyrene composite particles were synthesized by Pickering emulsion polymerization. ZnO nanoparticles were first prepared by reaction of zinc acetate and sodium hydroxide in ethanol medium. Then different amount of styrene monomer was emulsified in water in the presence of ZnO nanoparticles either by mechanical stirring or by sonication, followed by polymerization of styrene. Two kinds of initiators were used to start the polymerization, azobisisobutyronitrile (AIBN) and potassium persulfate (KPS). The X-ray diffraction pattern verified the crystal structure of ZnO and FT-IR spectra evidenced the existence of ZnO and polystyrene (PS) in ZnO/polystyrene composite particles. Different morphologies were observed for the composite particles when using different initiators. From TEM photographs, AIBN-initiated system produced mainly core-shell composite particles with PS as core and ZnO as shell, while KPS-initiated system showed both composite particles and pure PS particles. Two schemes of reaction mechanism were proposed to explain the morphologies accordingly. Both systems of composite particles showed good pH adjusting ability.     

ZnO/Ag微米球的合成与光催化性能

用微波辅助多元醇法对预先制备的ZnO微米球进行修饰,合成了载银氧化锌微米球（ZnO/Ag）. 利用X射线衍射仪、场发射扫描电子显微镜、透射电子显微镜、X射线光电子能谱仪、紫外-可见双光束分光光度计和光致发光光谱仪等对样品的结构、形貌和光学性能进行了表征. 在紫外光照射下,通过亚甲基蓝的降解反应研究了样品的光催化活性. 结果表明,所制备的ZnO/Ag微米球是由面心立方的Ag纳米颗粒附着在纤锌矿结构的ZnO球表面形成;与ZnO相比,ZnO/Ag的紫外-可见光吸收光谱发生明显红移,在紫外和可见光范围均有较强的吸收;随着Ag含量的增加,ZnO/Ag荧光光谱强度先减弱后增强;与ZnO相比,ZnO/Ag的光催化活性明显提高,AgNO₃ 浓度为0.05 mol/L时制得的ZnO/Ag光催化活性最高.     

Novel ZnO-Al2O3 composite particles as sorbent for low temperature H2S removal

ZnO-Al₂O₃ composite particles composed of ZnO nanosheets（thickness of 40-80 nm） on alumina particles were prepared by heterogeneous precipitation method using bayerite seed particles.The asprepared composite particles were characterized in terms of crystal structure,morphology,surface area and pore volume.The composite particles were used as sorbent for H₂S adsorption at low temperature, and were compared with pure ZnO sorbent.The composite sorbent showed a greater sulfur adsorption capacity（0.052 g/g） than pure form of ZnO（0.028 g/g）.This significant improvement was mainly attributed to higher surface area,more pore volume and unique morphology in nanoscale,which were also obtained by low cost presented method in this work for synthesis of ZnO sorbent supported on alumina particles.     

Investigating the effect of ultrasonic irradiation on preparation and properties of conductive nanocomposites

In the present study, the ultrasonic irradiation technique was employed as a new approach to prepare 0-3-dimensional polyaniline/ZnO shell-core composite particles. By taking advantage of the multiple effects of ultrasound, one can break down the aggregates of nanocrystalline ZnO particles. The polymerization of aniline proceeded while the nanoparticles were redispersed by ultrasound, and the synthesized polyaniline deposited on the ZnO particle, which formed polyaniline-coated nanocrystalline composite particles. The material was characterized by using transmission electron microscopy, XRD, scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and Thermogravimetric analysis (TGA). With increased ZnO content, the H-bonding interaction is strengthened and the characteristic peaks of benzoid and quinoid are shifted. X-ray photoelectron spectroscopy (XPS) shows that the ratio of the number of Zn and N atoms (Zn/N) on the surface is lower than that in the bulk. This is strong evidence for a PANI-encapsulated ZnO nanoparticles structure. The conductivity of the composites obtained through ultrasonic irradiation decreases with increasing ZnO content. Ultrasonic irradiation contributes to the increase in the conductivity compared with conventional stirring. Photocatalytic properties of PANI/ZnO nanocomposites were examined by degrading Reactive Black 5 (RB5) dye under visible light irradiation.     

Fabrication of zinc oxide/poly(styrene) grafted nanocomposite latex and its dispersion

Zinc oxide nanoparticles, with an average size of about 40 nm, were encapsulated by polystyrene using in situ emulsion polymerization in the presence of 3-methacryloxypropyltrimethoxysilane (MPTMS) as a coupling agent and polyoxyethylene nonylphenyl ether (OP-10) as a surfactant. Polymerization mechanism of nanocomposite latex was discussed. Transmission electron microscopy (TEM) proved the presence of ZnO nanoparticle appeared to be monodisperse in nanosize in polymer composite particles. ZnO/PS nanocomposites were characterized by Fourier transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy (XPS), thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results of FT-IR and XPS revealed that the surface of ZnO particle was successfully grafted by PS through the link of the coupling agent between ZnO and polymer. TGA and DSC results indicated an enhancement of thermal stability of composite materials compared with the pure polymer. SEM (scanning electron microscope) images showed a perfect dispersion of the ZnO particles in latex film. In addition, UV-visible absorption measurements demonstrated that the ZnO/PS composite coatings display a perfect performance of absorbing UV light.     

Enhanced activity of CuO/ZnO catalyst on the decomposition of dimethylhexane-1,6-dicarbamate into dimethylhexane-1,6-diisocyanate

To decompose dimethylhexane-1,6-dicarbamate (HDC) to hexamethylene diisocyanate (HDI), mixed CuO and ZnO catalysts with Cu/(Cu?+?Zn) ratio of 4 and 8% were prepared by coprecipitation (CP), sequential precipitation (SP) and incipient wetness impregnation (IW). The SP-derived CuO/ZnO catalysts showed higher HDC yields than those derived by CP and IW. The IW method produced CuO/ZnO catalysts consisting of larger CuO and ZnO particles compared to the two precipitation methods. The CP method led to substitution of Zn²⁺ by Cu²⁺ in the hydrozincite precursor phase, resulting in higher BET and Cu surface areas of CuO–ZnO catalysts due to intimate intergrowth of nano-sized particles. However, the inherent character of ZnO in the CP-derived catalysts was modified by interfacial contact between CuO and ZnO identified by UV–visible and Raman spectra. In contrast, the properties of CuO and ZnO, as well as the relatively large surface areas, were kept in the SP-derived catalysts owing to deposition of Cu precipitates to fully aged Zn precipitates. This is believed to be a benefit of the SP method for the reaction. Therefore, our preparation approach has great potential to be extended to various mixed oxide catalysts.     

Characteristics of ZnO Particles Prepared by Au-catalyzed Phase Transport Technique

ZnO particles were prepared by Au-catalyzed vapor phase transport method on silicon substrate. Scanning electron microscopy(SEM) images show many ZnO particles were formed on the sample surface. They grew up layer by layer along the c-axis, which was confirmed by the results of X-ray diffraction(XRD). The morphology of ZnO particles is close to hemisphere and its formation process could be seen from the SEM image. The room temperature photoluminescence(PL) measurement revealed a narrow UV emission peak at 3.27 eV and a broad green emission peak at 2.45 eV, which was caused by the near-band-edge and deep-level emissions.     

Effect of Zinc Oxide on Morphology and Mechanical Properties of Polyoxymethylene/Zinc Oxide Composites

This paper studies the effects of zinc oxide (ZnO) on morphology and mechanical properties of pure polyoxymethylene (POM) and POM/ZnO composites. POM/ZnO composites with varying concentration of ZnO were prepared by melt mixing technique in a twin screw extruder. The dispersion of ZnO particles on POM composites was studied by scanning electron microscope (SEM). It is observed that the dispersion of ZnO particles is relatively good. The mechanical properties of the composites such as tensile strength, stress at break, Young's modulus and impact strength were measured. Increasing content of ZnO up to 4.0 wt% increases the impact strength of POM. Addition of ZnO beyond 4.0 wt% decreases the impact strength. The composites containing ZnO content greater than 2.0 wt% show increased Young's Modulus. The tensile strength and stress at break decrease with increasing ZnO content. This may be due to the compatibility between ZnO and POM.