A facile synthesis of hierarchical flower-like TiO2 with enhanced photocatalytic activity

The hierarchical flower-like TiO₂ has been achieved by using a simple solvothermal process without any surfactants or colloidal crystals as a template. The structures of the products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption–desorption analysis. The relationship between hierarchical structure and photocatalytic performance has been presented based on detailed characterizations. It was found that the hierarchical flower-like structure was a benefit for light absorption and significantly enhanced the photocatalytic activity.     

花状TiO2分级结构的可控合成与其光催化性能

采用水热法可控合成了花状TiO₂分级结构材料,运用扫描电镜、透射电镜、X射线衍射、N₂物理吸附-脱附等手段,对其进行了表征,系统研究了NaOH用量、H₂O₂浓度、HNO₃浓度、反应温度及时间等因素对所得样品形貌的影响,并评价了它们的光催化性能.结果表明,花状TiO₂分级结构为锐钛矿相,颗粒大小均一;随制备条件的变化,构成花状TiO₂分级结构的基元结构分别为纳米线、纳米片,纳米线直径约25nm,纳米片厚度不足10nm;该样品具有较高的比表面积,表现出良好的单次光催化活性与重复使用性能.     

Controllable synthesis of NiC2O4·2H2O nanorods precursor and applications in the synthesis of nickel-based nanostructures

A controllable synthesis of NiC₂O₄·2H₂O nanorods precursor was obtained via the microemulsion-mediated solvothermal method and a further synthesis of β-Ni(OH)₂ nanorods, nickel oxide (NiO) sub-microtubes, Ni nanospheres and flower-like nickel complexes nanostructures by using the precursor. The morphologies and crystalline structures were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and the X-ray powder diffraction (XRD). The morphologies and sizes of the precursors can be readily tuned by adjusting experimental parameters of the reverse microemulsion system. The synthesized β-Ni(OH)₂ nanorods composed of fine nanosheets shown excellent electrochemical performance as an electrode material in rechargeable battery systems.     

微波辅助水热法制备花状氧化铜

以硝酸铜为铜源,氨水为碱源,通过微波辅助水热法制备了花状CuO微纳米材料。制备过程中没有使用表面活性剂或离子液体等软模板剂。利用X-射线衍射、电子能谱、场发射扫描电镜以及高分辨透射电镜表征了产物的物相和形貌。对照实验显示碱源对产物形貌有着很大的影响。通过时间演化实验研究了花状CuO的生长过程。结果显示反应过程经历了Cu2(OH)3NO3和Cu(OH)2两种中间产物。     

花状硫化铜的合成及其光电催化性能

通过硫化介孔Cu_2O微球得到花状Cu_xS纳米催化材料,并采用丝网印刷法制备出Cu_xS/FTO对电极。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等表征手段对所得材料的结构和形貌进行了探究,同时系统考察了溶液浓度、硫化时间、催化剂印刷层数对Cu_xS/FTO电极的催化性能影响和所组装量子点敏化太阳电池的光电转换效率,其中基于Zn-Cu-In-Se量子点敏化的电池转换效率达8.80%,表现出花状Cu_xS优异的光电催化性能。     

钨酸锌纳米结构的水热合成及其光催化性能研究

使用柠檬酸钠辅助的水热法合成了具有不同形貌的ZnWO4(如片状、花状)纳米颗粒,并采用X-射线粉末衍射(XRD)、场发射扫描电子显微镜(FESEM)、高分辨透射电子显微镜(HRTEM)等方法对样品的结构和组成进行表征。研究了溶剂组分和溶液pH值对产物形貌的影响。通过对反应产物形貌随时间变化的观察,提出了片状和花状ZnWO4纳米颗粒可能的生长机理。以罗丹明B(RhB)为催化降解对象,对样品在水溶液中的光催化性质进行了研究。结果表明,ZnWO4纳米颗粒的比表面积和孔径尺寸等结构特性对其光催化活性具有明显影响。     

Preparation and electrochemical lithium storage of flower-like spinel Li4Ti5O12 consisting of nanosheets

In this paper, flower-like spinel Li₄Ti₅O₁₂ consisting of nanosheets was synthesized by a hydrothermal process in glycol solution and following calcination. The as-prepared product was characterized by scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction and cyclic voltammetry. The capacity of the sample used as anode material for lithium ion battery was measured. This structured Li₄Ti₅O₁₂ exhibited a high reversible capacity and an excellent rate capability of 165.8 m Ahg⁻¹ at 8 C, indicating potential application for lithium ion batteries with high rate performance and high capacity.     

简单的溶剂热法制备分层的碲化铋微米结构

采用简单的溶剂热法制备出高纯度的由纳米片自组装而形成的碲化铋微米结构。在碲化铋的形成中,乙二醇不仅作为溶剂,而且还作为还原剂。研究发现,聚乙烯吡咯烷酮(PVP)和硝酸在碲化铋的形成中起到了很重要的作用。通过X-射线衍射(XRD)、X-射线光电子能谱(XPS)、扫描电镜(SEM)、透射电镜(TEM)、高分辨透射电镜(HRTEM)、选区电子衍射(SAED)对其进行表征及研究。最后,利用时间演化实验对碲化铋的形成机理进行了探讨。     

表面活性剂对水热制备钨酸铋形貌及光催化性能的影响

通过简单水热制备了大小均一,直径约为2.5 μm的球状Bi2WO6粉体.系统研究表面活性剂SDS和PVP对水热制备Bi2WO6光催化剂的影响.利用XRD,EDS,SEM,TEM和DRS等分析技术对催化剂的组成、形貌、比表面积和带隙宽度等进行了表征.实验结果表明,表面活性剂对催化剂的形貌和催化活性有较大影响.在水热制备过...     

Facile Synthesis and Catalytic Properties of β-Co（OH）2 and Mg（OH）2 Nanoplates

β-Co(OH)2 and Mg(OH)2 nanoplates were synthesized via a facile template-free hydrothermal approach.The different conditions of preparation and catalytic properties of the products were studied and discussed.The products were characterized by X-ray diffraction,transmission electron microscopy,scanning electron microscopy,selected area electron diffraction(SAED),and gas chromatograph.     

三维花状ZnO纳米材料的制备及发光性质

常压下用溶胶凝胶和化学溶液生长两步法在3种不同的衬底上制备出三维花状ZnO纳米材料.采用X射线衍射仪(XRD)、扫描电镜(SEM)、透射电镜(TEM)、选区电子衍射(SAED)、紫外吸收(UV)光谱和光致发光光谱(PL)对样品进行分析,结果表明,花状ZnO的组成单元为沿c轴方向生长的ZnO纳米棒,直径约为100 nm,...     

Synthesis and characterization of hierarchically structured mesoporous MnO2 and Mn2O3

Hierarchically structured mesoporous MnO₂ with high surface area was prepared by a facile precursor route. Well-defined morphological manganese oxalate, synthesized by adding l-lysine via a hydrothermal method, was used as precursor. Mesoporous amorphous MnO₂ with high Brunauer–Emmett–Teller (BET) surface area (340 m²/g) and mesoporous Mn₂O₃ composed of nano-crystals (BET surface area 188 m²/g) were obtained by selective calcination of the oxalate precursor at 330 °C and 400 °C, respectively. Thermogravimetric and differential thermal analyses (TG–DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂-sorption analysis and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure and property of products. Cyclic voltammetry (CV) and charge–discharge measurements were used to preliminarily study the electrochemical performance of the products. The range of pH value (about 5.0–7.0) in the synthesis process is apt to prepare the hierarchical structured manganese dioxide. Other types of amino acids were also employed as the crystallization modifiers and different morphologies of manganese dioxides were obtained.     

Fabrication and photocatalytic properties of SnO2 double-shelled and triple-shelled hollow spheres

SnO₂ double-shelled and triple-shelled hollow spheres were tailored by adjusting concentration of tin (IV) chloride solution during the process of the tin (IV) ions infused carbonaceous spheres. The structures of these SnO₂ multi-shelled hollow spheres were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and their possible formation mechanism were also discussed. In virtue of triple-shelled hollow porous structure and higher specific surface area, SnO₂ triple-shelled hollow spheres exhibited enhanced photocatalytic properties compared to SnO₂ double-shelled hollow spheres.     

Study of photocatalytic activity of Cd-doped mesoporous nanocrystalline TiO2 prepared at low temperature

Mesoporous nanocrystalline Cd-doped titania was firstly prepared at low temperature by a modified sol–gel method, using dodecylamine as a template. The template could be easily removed by refluxing samples in nitric acid ethanol solution. The Fourier transform infrared spectrometer (FT-IR), low-angle and wide-angle X-ray diffraction (XRD), N₂ adsorption–desorption, transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), and UV–visible diffuse reflectance spectroscopy were used for the characterization of catalysts. The characteristic results clearly showed that Cd²⁺ ions were doped into the titania lattice, and the mesoporous architecture of Cd-doped TiO₂ was composed of mixed-phase crystal textures of anatase and brookite. The samples displayed high visible-light photocatalytic activity for photodegradating 2,4-dichlorophenol (2,4-DCP) solution. The high activities of samples were attributed to the bicrystalline framework, large BET surface area, small crystallite size, and Cd-doping.     

Phase-controlled solvothermal synthesis and characterization of nickel sulfides with good single crystalline nature

Dispersed rhombohedral NiS rods with high aspect ratios and rhombic dodecahedron-like cubic NiS₂ crystals were prepared by solvothermal routes using NiCl₂·6H₂O and Na₂S₂O₃·5H₂O as reagents and ethylenediamine as a solvent, and 3D blossoming flower-like rhombohedral NiS microstructures were synthesized using different sulfur sources of thiourea. The products were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy dispersion spectrometry and selected area electronic diffraction. All the products were pure and had good single crystalline nature. The synthesis parameters were of great importance on the purity and morphology of the products. The possible growth mechanisms have been discussed based on the analyses of the effects of sulfur sources and solvent on the crystal structures and detailed configurations of the products. The present work is likely to help the phase-controlled synthesis of other metal chalcogenides.     

不同形貌ZnO纳米粒子的超声化学法制备与表征

One-dimensional ZnO nanorods and shuttle-like ZnO nanoparticles have been successfully achieved by ultrasonic irradiation of Zn (CH3COO)2 aqueous solution and Zn-NH3 complexcs solution. The obtained ZnO nanoparticles have been characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and selected area electronic diffraction (SAED). And the formative mechanism of the prepared different morphological ZnO nanoparticles is also discussed under ultrasonic irradiation.     

Parameters controlling the photocatalytic performance of ZnO/Hombikat TiO2 composites

Commercial TiO₂ (Hombikat, UV-100) was impregnated with different loadings of zinc nitrate solution and subsequently calcined at different temperatures in order to obtain a stable homogeneous solid composite of ZnO/TiO₂. The prepared samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM), UV-vis and Raman spectroscopy, inductively coupled plasma mass spectroscopy (ICP), X-ray photoelectron spectroscopy (XPS) as well as N₂ adsorption and desorption measurements. Results show that ZnO was incorporated within the TiO₂ crystals and did not form a separate bulky phase or metallic zinc. Moreover, the calcination temperature dramatically modifies the texture properties of the prepared samples compared with original Hombikat TiO₂. The photocatalytic performance of the prepared samples was evaluated by monitoring the degradation of methyl orange dye under black light illumination. Three main parameters were studied; ZnO loading, surface area and initial pH of the methyl orange solution. The variation in ZnO loading appears to have less influence on the catalytic activity than either the surface area or the pH.     

In2O3/CdO复合材料的制备及气敏特性

采用水热合成方法制备了花状In2O3纳米材料.利用X射线衍射(XRD)、扫描电镜(SEM)、能量色散X射线光谱(EDX)及透射电镜(TEM)对材料的结晶学特性及微结构进行了表征.制备的In2O3材料呈现花状,是由粒径约20nm的椭球状小颗粒构成的分级结构材料.将制备的In2O3与纳米CdO以摩尔比1:1混合后,发现制成的In2O3/CdO复合材料经热处理后呈现葡萄状多孔结构.测试In2O3/CdO复合材料制作的气敏元件处于最佳工作温度(410°C)时,对0.05×10-6(体积分数,φ)的甲醛气体表现出较高的灵敏度.对比测试发现,In2O3/CdO复合材料制作的气敏元件对不同浓度甲醛的灵敏度明显优于纯花状In2O3纳米材料.同时In2O3/CdO复合材料制作的气敏元件在乙醇、甲苯、丙酮、甲醇以及氨气等干扰气体中具有对甲醛良好的选择性.讨论了In2O3/CdO复合材料气敏元件的敏感机理.     

Sonochemical synthesis of mass single-crystal PbS nanobelts

Based on sonochemical technique, large-scale PbS nanobelts are successfully synthesized in the mixed solution of PbCl₂ and Na₂S₂O₃. These nanobelts are characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), selected area electronic diffraction, energy dispersive X-ray spectroscopy, and high-resolution TEM. The as-synthesized PbS nanobelts have width of about 80 nm, length up to several millimeters, and width-to-thickness ratio of about 5. In addition, the growth mechanism of PbS nanobelts is suggested.     

Synthesis and characterization of MFe2O4 sulfur nanoadsorbents

Nanoparticles of ferrites (Fe₃O₄, NiFe₂O₄, CuFe₂O₄, and MnFe₂O₄) were prepared by a reverse (water/oil) microemulsion method. The microemulsion system consisted of cetyltrimethylammonium bromide, 1-butanol, cyclohexane, and a metal salt solution. The procedure was carried out using aqueous ammonia as the coprecipitating agent. Nanosized particles were characterized by thermal analysis, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and pyridine adsorption. The NiFe₂O₄ sample exhibited narrow mesoporous pore size distribution and high surface area ≈233 m²/g. It achieved good adsorption activity towards the dibenzothiophene (DBT) compound (166.3 μmol/g of DBT adsorbent). The structural properties obtained were very interesting for potential applications in the desulfurization process in petroleum refining.