铂纳米花的控制合成

以氯铂酸钾（K2PtCl6）为前驱体、聚乙烯吡咯烷酮（PVP）为稳定剂及还原剂,在一定量溴化钾（KBr）的存在下,采用水热法制备了铂纳米花。考察了n（K2PtCl6）∶n（PVP）∶n（KBr）、反应温度、反应时间对产物形貌的影响。结果表明,在n（K2PtCl6）∶n（PVP）∶n（KBr）为1∶10∶15、反应温度为130℃、反应时间为3h的条件下,制备出形貌规则、大小均匀的花形自组装铂纳米颗粒。利用透射电子显微镜、X-射线光电子能谱和X-射线粉末衍射对产物进行了表征。所制备的铂纳米花由零价态的铂原子组成,具有面心立方（fcc）结构。     

由稻壳制备纳米结构SiO2

以稻壳为原料制备纳米结构SiO2,并用X-射线衍射、扫描电镜、透射电镜以及小角X-射线散射对其结构进行了表征。结果表明,由稻壳制备的SiO2具有分层结构：由硅氧四面体无规连接构成粒径为4nm左右、表面分形维数Ds≈2．3的一次粒子;一次粒子聚集成粒径30～50nm、质量分形维数Dm≈2．7的二次粒子。     

表面活性剂对氧化锌微晶形貌的影响

采用简单的低温液相法，通过添加表面活性剂成功制备出不同形貌的氧化锌微晶。用X射线衍射（XRD）和扫描电子显微镜（SEM）分别对产物的结构和形貌进行了表征。结果表明，在反应体系中添加0．01mol／L的十二烷基硫酸钠（SDS），使生成产物的形貌由原来的棒状变为孪生螺帽状氧化锌；相同条件下用0．1mol／L三乙醇胺（TEA）替代SDS，则得到一种麦粒状氧化锌晶体。并初步探讨了表面活性剂SDS和TEA对氧化锌晶体生长的作用机理。     

文石晶须制备中氯化镁的影响

采用碳酸化法制备了文石CaCO3晶须，分析了合成晶须过程中MgCl2的作用机理，运用扫描电镜和X射线衍射对产物进行了表征。结果表明：由MgC2形成的Mg(OH)2胶状沉淀作为晶种促进晶须成核，并抑制了文石晶须向方解石转变。在确定的工艺条件下，利用回收的MgCl2溶液制备了文石CaCO3晶须，降低了文石晶须的制备成本。     

TEA协助层状LZH到ZnO纳米材料控制生长机制研究

三乙醇胺(TEA)协助下类水滑石氢氧化物碱式硝酸锌(LZH)结构到二维层状氧化锌纳米片(ZnO)转变及其性能研究相对较少。以Zn(NO3)2为锌源,借助于三乙醇胺/水体系,研究制备LZH和二维氧化锌纳米片工艺条件及影响合成层状LZH和氧化锌纳米材料的各种因素。利用X-射线粉末衍射(PXRD)、扫描电镜(SEM)、红外光谱(FT-IR)、荧光光谱(PL)等技术手段对其进行解析和表征,探讨层状碱式硝酸锌和氧化锌纳米材料之间的转变机制。结果表明:在研究范围内,温度和反应时间的改变不会影响产物的组成和结构,TEA用量直接影响到合成的目标产物。首先生成Zn(OH)2,其次转化为Zn5(OH)8(NO3)2·2H2O,过渡生成[Zn5(OH)10-x·2H2O]x+,最终自组装形成层状ZnO二维纳米材料,从而实现无需焙烧,通过控制TEA用量制备ZnO二维纳米材料的方法。     

乙醇超临界干燥制备二氧化锰超细粉体

以MnCl2和NaOH为原料,利用超临界流体干燥技术(SCFD)制备了MnO2超细粉 体,采用X-射线衍射、粒度分析和扫描电镜确定了粒子的形貌和粒径,结果表明,采用超临界流 体干燥技术可以制备出颗粒细、大小均匀的纳米粒子。     

四氧化三锰的简易制备及其作为电池阳极材料的电化学性能研究

在90℃下,采用空气氧化法于弱碱性介质中氧化Mn2+制备Mn3O4。X-射线衍射和扫描电镜表明,产物为四方结构的Mn3O4,纯度高、结晶良好,具有近似球形形貌。电化学测试结果表明,在50 mA/g的电流密度下,Mn3O4作为阳极材料的初始放电容量为198 mA.h/g。在不同电流密度下循环50次后,放电容量基本可以回到初始值。     

基于温度调控制备花状纳米氧化锌及其光催化性能

以醋酸锌、柠檬酸钠、氢氧化钠为原料,采用沉淀法制备了片层交叉花状纳米氧化锌。利用扫描电镜(SEM)、X射线衍射(XRD)、Zeta电位对所得样品进行了表征。通过考察温度对样品形貌的影响,对产物的生长机理做了简单研究。并以罗丹明B为模型分子,采用紫外-可见光谱(UV-Vis)考察了样品的光催化性能。研究结果表明:在不同温度下得到的产物形貌存在着明显区别。在25℃条件下制备的氧化锌为片层交叉花状。该纳米材料在紫外-可见光下具有较高的光催化活性和稳定性,照射12 h可以使罗丹明B的降解率接近100%。样品的Zeta电位为-13.2 e V,表明样品可能存在结构缺陷,花状氧化锌纳米球粒子有大量的Zn2+空位或过剩的O2-。同时样品具有较大的比表面积,因此在可见光条件下的催化活性与紫外光下的催化活性相近。     

用氧化锌矿制备纳米级氧化锌

报道了从氧化锌矿制备的米级氧化锌的优惠工艺条件，并对所制得的氧化锌产物进行了Ｘ射线衍射分析，证明所得产品为高纯钠米级氧化锌粉。     

二氧化锰的制备及其对高氯酸铵和黑索金的催化性能

以KMn O4为锰源、CO(NH2)2为还原剂,在90℃水热条件下通过氧化还原反应制备Mn O2。采用X-射线衍射、扫描电镜和红外光谱等技术对所得产物进行表征。利用差示扫描量热技术研究了Mn O2对高氯酸铵(AP)和黑索金(RDX)热分解行为的影响,进行了热分解动力学分析,并探讨了二元体系的相容性。结果表明,Mn O2的添加使AP的分解过程提前,但对RDX的分解峰温影响很小。     

Synthesis and characterization of twinned flower–like ZnO structures grown by hydrothermal methods

Twinned flower-like ZnO structures have been synthesized by one-step CTAB assisted hydrothermal methods at a low-temperature as 90 °C. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results disclosed a twinned flower-like morphology and hexagonal wurtzite structures. The XRD pattern and temperature-dependent PL results show a mixed structure of as-grown samples, which are confirmed by the SEM results. The CL spectrum on a single twinned flower-like ZnO structures showed an excellent optical property. Based on experimental results, self-etching and regrowth are suggested as the mechanism to grow the flower-like structures.     

Morphological evolution of flower-like ZnO microstructures and their gas sensing properties

Flower-like ZnO microstructures have been fabricated by a facile microwave hydrothermal method (HM) with the aid of benzoic acid. The obtained products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The morphology gradually evolved from flower bud shape to fireworks display with increase of alkalinity in the presence of benzoic acid. The formation mechanism of the flower-like ZnO microstructures was investigated briefly. Furthermore, the gas response of the flower-like ZnO microstructures has been studied to a series of organic vapors. It was found that the gas sensing properties were influenced by the size of the ZnO microstructures. The facile preparation method and the improved gas-sensing properties derived from the flower-like ZnO microstructures demonstrated their potential applications in gas sensor.     

Sol−gel-based hydrothermal method for the synthesis of 3D flower-like ZnO microstructures composed of nanosheets for photocatalytic applications

Self-assembled 3D flower-like ZnO microstructures composed of nanosheets have been prepared on a large scale through a sol−gel-assisted hydrothermal method using Zn(NO₃)₂·6H₂O, citric acid, and NaOH as raw materials. The product has been characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The optical properties of the product have been examined by room temperature photoluminescence (PL) measurements. A possible growth mechanism of the 3D flower-like ZnO is proposed based on the results of experiments carried out for different hydrothermal treatment times. Experiments at different hydrothermal treatment temperatures have also been carried out to investigate their effect on the final morphology of the ZnO. The photocatalytic activities of the as-prepared ZnO have been evaluated by photodegradation of Reactive Blue 14 (KGL) under ultraviolet (UV) irradiation. The experimental results demonstrated that self-assembled 3D flower-like ZnO composed of nanosheets could be obtained over a relatively broad temperature range (90−150 °C) after 17 h of hydrothermal treatment. All of the products showed good photocatalytic performance, with the degree of degradation of KGL exceeding 82% after 120 min. In particular, the sample prepared at 120 °C for 17 h exhibited superior photocatalytic activity to other ZnO samples and commercial ZnO, and it almost completely degraded a KGL solution within 40 min. The relationship between photocatalytic activity and the structure, surface defects, and surface areas of the samples is also discussed.     

Synthesis of flower-like 3D ZnO microstructures and their size-dependent ethanol sensing properties

Flower-like 3D ZnO microstructures constructed from nanorods of different sizes were prepared by a microwave hydrothermal (MH) process in the presence of o-, m- and p-nitrobenzoic acid, respectively. Well-crystallized flower-like ZnO microstructures were obtained after 10 min MH treatment. The X-ray powder diffraction (XRD) test indicated that all the products were consistent with the hexagonal ZnO phase, and scanning electron microscopy (SEM) investigation revealed that the flower-like 3D ZnO microstructures were built with sword-like nanorods 60-100 nm in width and several micrometers in length. The formation mechanism of these flower-like 3D ZnO microstructures is discussed briefly. The gas sensitivity of the as-prepared ZnO microstructures to ethanol at different operation temperatures and concentrations was also studied. The results indicated that the gas sensitivity of the ZnO microstructures was influenced by the particle size and microcosmic configuration, the larger particles with crowded nanorods having higher gas sensitivity.     

Synthesis and characterization of 3D ZnO superstructures via a template-free hydrothermal method

The ZnO microrods and flower-like 3D superstructures have been synthesized via a template-free hydrothermal method. The prepared ZnO samples are characterized by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). It is found that the flower-like 3D ZnO superstructures can be obtained simply by tuning the volume ratio of Zn(OH)₂⁴⁻ precursor solution to water, or the volume ratio of ethylene glycol to water. When the volume ratio of Zn(OH)₄²⁻ precursor solution to water is 1:7, the flower-like 3D ZnO superstructures are obtained, in which the diameter of an individual pencil-like rod is about 1.0 μm, and the tip size is several nanometers. While when the volume ratio of Zn(OH)₄²⁻ precursor solution to ethylene glycol (EG) is 1:1, the flower-like 3D ZnO superstructure consists of hexagonal rods with about 500 nm in diameter. A plausible formation mechanism of flower-like 3D ZnO superstructures is discussed in detail.     

Controllable preparation of ZnO porous flower through a membrane dispersion reactor and their photocatalytic properties

Three dimensional (3D) flower-like basic zinc carbonate constructed by multilayered nanoplates were rapidly prepared at room temperature through the direct precipitation method coupled with membrane dispersion technology, and porous ZnO with similar structures could be obtained after calcining the precursor. The structural properties of the products before and after the calcining process were characterized by SEM, TEM and XRD. The supersaturation of the reaction system due to the membrane dispersion played an important role in the formation of uniform Zn₅(CO₃)₂(OH)₆ precursors. A plausible mechanism was proposed for the formation of the flower-like ZnO assembled by nanoplates composed of nanoparticles. The obtained ZnO microspheres showed excellent photocatalytic properties, which could be attributed to the open structure and remarkable amount of porous nanoplates.     

可控形貌纳米ZnO制备及光催化应用研究

采用醇辅助水热法,不添加任何表面活性剂,不经过特殊处理,通过优化无水乙醇与水的体积比分别为3∶1,1∶1,1∶19,控制纳米颗粒生成形貌,制备颗粒状、棒状和花状3种纳米ZnO颗粒。利用X射线衍射(XRD)、扫描电镜(SEM)及紫外-可见漫反射光谱(UV-vis)等手段对产物进行表征,分析生长机理。将3种不同形貌ZnO纳米粒子用于光催化降解低浓度偏二甲肼(UDMH)废水,结果表明,颗粒状纳米ZnO对偏二甲肼废水的降解效率最高可达46.8%。     

片状花形ZnO制备及其对三甲胺的气敏性能

采用低温水热法制备了ZnO材料,通过X射线衍射仪和扫描电镜分别对其结构和形貌进行了表征,并采用气敏测试仪对所制ZnO材料对三甲胺的气敏性进行了测试. 结果表明,所得的ZnO材料具有六方纤锌矿结构,呈片状花形. 此材料在340℃,对体积分数为1.00′10?4三甲胺气体的灵敏度可达到63.72. 随着三甲胺浓度的增加,灵敏度呈现线性增加的趋势. 响应时间和恢复时间分别为4 s和21 s. 此外,该样品具有呈现良好的选择性、重复性和长期稳定性.     

花状形貌层状氧化锰的制备与表征

在微酸性环境中高锰酸钾自身分解,利用低温水热法制备了花状形貌的Birnessite型层状氧化锰。探讨了温度及表面活性剂对其形貌的影响。采用XRD、 SEM、 N2吸附-脱附实验等手段对所合成的多孔材料进行了表征。花状形貌的层状氧化锰在 1 mol/L 的硫酸钠溶液中,扫描速度为 5 mV/s 时显示出较高的比电容,其比电容达到 190 F/g。     

Synthesis of large-scale uniform mulberry-like ZnO particles with microwave hydrothermal method and its antibacterial property

Large-scale uniform mulberry-like ZnO particles were successfully synthesized via a fast and simple microwave hydrothermal method. The formation mechanism of mulberry-like ZnO particles was investigated by adding different types of alkalis and different amounts of triethanolamine (TEA). Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to observe the morphology and crystal structure of the obtained ZnO. The results revealed that the as-prepared ZnO products had an average diameter of about 150 nm and polycrystalline wurtzite structure. The existence of TEA was vital for the formation of nanoparticle-assembled mulberry-like ZnO particles. These mulberry-like ZnO particles exhibited stronger antibacterial effects on Candida albicans than did sheet-like and flower-like ZnO.