基于同步辐射光源研究水热合成纳米氧化物的生长机理

纳米氧化物的可控制备是提高其应用性能的前提条件。水热反应目前被广泛用于制备纳米氧化物材料,然而由于水热反应是在密闭环境中进行,很难研究前驱体的溶解过程,溶解后在溶液中的配位情况、晶体成核、生长过程以及形成的中间相,因此,难以实现材料的目标制备。同步辐射具有高强度、高亮度、高准直、宽频谱等诸多优点,通过设计和构建特殊的反应装置,可以应用同步辐射光源原位研究纳米氧化物在水热条件下的生长过程。本文结合本课题组及国际的研究工作介绍了原位反应装置的设计原则,以及基于同步辐射光源的原位X射线衍射(XRD)、X射线吸收精细结构谱(XAFS)和小角X射线散射(SAXS)研究纳米氧化物水热生长机理的最新进展,并展望了其发展趋势。     

Synthesis of a new complex Chromium (Ⅲ) 2-mercaptonicotinate

Chromium is an essential trace element for mammals[1-3].Diabetes is a chronic disease with major health consequence. Studies show that the occurrence of diabetes have great thing to do with the chromium deficient. Almost 40 years after the first report of glucose tolerance factor(GTF)[4]no conclusive evidence for an isolable ,biologically active form of chromium exited. Three materials have been proposed to be the biologically active form of chromium: "glucose tolerance factor", chromium Picolinate and low-molecular-weight chromium-binding substance (LWMCr)[5]So there is potential for the design of new chromium drugs[6].Chromium compounds have been used in medicine for centuries and there is potential for the design of new chromium drugs.2-Mercaptonicotinic acid(MN) displays the interesting biological activity. Chromium( Ⅲ )2-mercaptonicotinate is a common and effective biologically active form of Chromium. The test of biological activity indicated that may be useful in treating of diabetes. In this paper, we reported the The synthesis route is as follow:The structure of the complex has been characterized by IR, elemental analysis, MS,atomic absorption spectroscopy, X-ray powder diffraction and TG-DTA analysis.They indicate that the structure of Chromium 2-mercaptonicotinate.HPLC is used for determination of the purity. Studies show that the complex has a good biological activity for supplement tiny dietary chromium,lowering blood glucose levels, lowering serum lipid levels and increasing lean body mass.     

钼酸铋纳米片的制备以及光催化性能测试*

以硝酸铋与磷钼酸为原料,通过水热反应制备高催化活性光催化剂,应用X射线衍射和扫描电子显微镜进行材料表征,通过以氙灯为光源研究材料对四环素的表面光催化降解的特性。本实验涉及无机纳米材料的水热合成、结构表征以及有机类污染物光催化降解应用,将无机化学、物理化学、有机化学和分析化学的理论内容、实验方法与科学研究前沿相结合,能够全方位提升本科大学生的综合实验技能及科学研究水平。     

Hydrothermal synthesis and reactivity of rhodium dioxide and oxyhydroxide

The hydrothermal synthesis, interrelations and thermal decomposition of RhOOH and RhO₂ in different atmospheres are studied. Although the final product of the decomposition is always rhodium metal, there is a marked influence of the atmosphere on the intermediate products. The reactions that have been observed include the disproportionation of RhOOH in vacuum and the hydrothermal reduction of the dioxide to the oxyhydroxide.     

The progress of microwave-assisted hydrothermal method in the synthesis of functional nanomaterials

Developing simple, rapid, and environmentally friendly synthetic methodologies for the preparation of functional nanomaterials is of great importance for broadening and improving their potential applications. In comparison with other methods, the microwave-assisted hydrothermal method possesses and combines the merits of microwave and hydrothermal methods, which can achieve the high temperature and high pressure for a short time from several minutes to several hours in a closed reaction system. In this review, the synthesis of various types of functional nanomaterials such as metals oxides, metal composite oxides, inorganic biomaterials (hydroxyapatite and calcium carbonate), and metal sulfides via the microwave-assisted hydrothermal method is summarized. The special properties and applications of functional nanomaterials by the microwave-assisted hydrothermal method are compared with others methods. The future developments of this promising method are put forward.     

Chromium wheels quasi-hexagonal 2D assembling by direct UHV sublimation

Chromium(III)-based wheels close-pack on the Ag(110) surface forming a quasi-hexagonal 2D network following direct sublimation in ultra high vacuum (UHV). Wheels organization and chemical integrity have been proved through in situ Scanning Tunneling Microscopy (STM) and X-ray Photoelectron Spectroscopy (XPS) studies.     

TiO_2一维纳米材料及其纳米结构的合成

本文对合成TiO2一维纳米材料及其有序纳米阵列的阳极氧化法、模板法以及水热法进行了全面而系统的评述,着重介绍了它们的最新研究进展。阳极氧化法能制备牢固负载于基体上的TiO2纳米管阵列,这有助于构筑TiO2纳米结构及其在纳米器件上的应用;与多种制备技术如溶胶-凝胶工艺、电化学沉积以及原子层沉积等相结合,模板法可以合成出多种形貌的TiO2纳米材料如纳米管、纳米线和纳米棒,并且可以通过改变所用模板的微观尺寸来调控TiO2一维纳米材料及其有序阵列的微结构参数;水热合成法可以制备出直径小且比表面积大的TiO2纳米管粉末。从目前来看,该法还不能制备出牢固负载于基体上的有序纳米阵列。文章最后指出了TiO2一维纳米材料及其有序纳米阵列合成中存在的问题及今后发展方向。     

Chromium removal technologies

Chromium can exist in different oxidation states (e.g. 0, III, VI). Chromium can be both beneficial and toxic to animals and humans depending on its oxidation state and concentration. At low concentration, Cr(III) is essential for animal and human health. Chromium(VI) compounds are highly soluble, mobile and bioavailable compared to trivalent chromium. Chromium(VI) is dangerous for humans due to its toxicity and carcinogenic properties. The presence of hexavalent chromium in waste water is a potential hazard to aquatic animals and humans. Various methods are adopted for the removal of hexavalent chromium from industrial effluents. Among these different techniques, biosorption is the most promising one. In this process, the various components present in biomaterial reduce the toxic hexavalent chromium to non-toxic trivalent chromium. Algae, fungi and bacteria have biosorption properties, and cell walls are responsible for biosorption of dead biomaterial. But this process removes chromium from waste water very slowly. So for chemical modification of biosorbents, optimization of biosorption parameters is required to increase the effectiveness of this process.     

Hydrothermal Synthesis and Characterization of Nd Doped One-dimensional Hexagonal CePO_4 Nanowires

One-dimensional Nd doped CePO4 hexagonal nanowires have been synthesized for the first time at 140 ℃ for 24 hours via a hydrothermal method using P123 surfactant as the template.The products were characterized by X-ray diffraction,transmission electron microscopy,photoluminescence and high-resolution transmission electron microscopy.Compared with CePO4,one-dimensional nanomaterials we have synthesized,Nd doped CePO4 nanomaterials remain their hexagonal one-dimensional morphology and smooth surface.However,their photoluminescence emissions are greatly enhanced at the wavelength of 348 nm.With their novel fluorescence-emission property,the Nd doped CePO4 nanomaterials are potential in many fields such as optics and electronics.     

Well-defined BiOCl colloidal ultrathin nanosheets: synthesis,characterization, and application in photocatalytic aerobic oxidation of secondary amines

We demonstrate the first colloidal synthesis of single-crystalline BiOCl ultrathin nanosheets (UTNSs) that feature a well-defined square morphology. Unlike BiOCl nanomaterials prepared by hydrothermal routes, our colloidal BiOCl UTNSs exhibit hydrophobic surface properties and high activity and selectivity toward the photocatalytic aerobic oxidation of secondary amines to corresponding imines at room temperature. Hence, the application of BiOCl nanomaterials has been successfully extended from the widely studied photodecomposition of pollutants in aqueous solution to the synthesis of fine chemicals in organic solvent using a green approach.     

A simple hydrothermal route to synthesis of rod-like MnOOH and spindle-shaped MnCO3

A simple hydrothermal route was developed to synthesis of rod-like manganese oxyhydroxide (MnOOH) and spindle-shaped manganese carbonate (MnCO₃) based on the redox reactions between potassium permanganate (KMnO₄) and ??-cyclodextrin (??-CD) without extra surfactant or template. At the mass ratio between ??-CD and KMnO₄ of 0.25, MnOOH nanorods with the diameter about 40?C400?nm and the length in the range of 2?C10???m could be facilely prepared in high yield. However, spindle-shaped MnCO₃ microparticles were prepared when the mass ratio between ??-CD and KMnO₄ was increased to 1.5. The as-prepared products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and high-resolution transmission electron microscopy. The formation mechanisms of rod-like MnOOH and spindle-shaped MnCO₃ were preliminarily discussed.     

Synthesis of Cyclic Carbonates Catalysed by Chromium and Aluminium Salphen Complexes

Chromium and aluminium salphen complexes have been found to display remarkable catalytic activity in the synthesis of cyclic carbonates from a range of epoxides and carbon dioxide. The Al(salphen) complex is more reactive towards terminal epoxides at ambient temperature and pressure, whereas the Cr(salphen) complex exhibits higher catalytic activity towards more challenging internal epoxides at elevated temperature and pressure.     

Hydrothermal Synthesis of Chromium Dioxide

Two procedures for hydrothermal synthesis of chromium dioxide are compared: from chromi- um(VI) oxide and from chromium(VI) and chromium(III) oxides. The reaction products obtained in the presence of modifying agents such as antimony, iron, tellurium, and tin compounds are described in relation to the synthesis temperature.     

TiO2一维纳米材料及其纳米结构的合成

本文对合成TiO₂一维纳米材料及其有序纳米阵列的阳极氧化法、模板法以及水热法进行了全面而系统的评述，着重介绍了它们的最新研究进展。阳极氧化法能制备牢固负载于基体上的TiO₂纳米管阵列，这有助于构筑TiO₂纳米结构及其在纳米器件上的应用；与多种制备技术如溶胶－凝胶工艺、电化学沉积以及原子层沉积等相结合，模板法可以合成出多种形貌的TiO₂纳米材料如纳米管、纳米线和纳米棒，并可以通过改变所用模板的微观尺寸来调控TiO₂一维纳米材料及其有序阵列的微结构参数；水热合成法可以制备出直径小且比表面积大的TiO2纳米管粉末。但从目前看来，该法还不能制备出牢固负载于基体上的有序纳米阵列。文章最后指出了TiO₂一维纳米材料及其有序纳米阵列合成中存在的问题及今后发展方向。     

Synthesis of Chromium (Ⅲ) 5-aminosalicylate

As we all known that diabetes is a chronic disease with major health consequences.Research has revealed that the occurrence of diabetes have great thing to do with the chromium deficient. Almost 40 years after the first report of glucose tolerance factor(GTF) [1], no conclusive evidence for an isolable ,biologically active form of chromium exited. Three materials have been proposed to be the biologically active form of chromium: "glucose tolerance factor", chromium Picolinate and low-molecular-weight chromium-binding substance (LWMCr) [2] . So there is potential for the design of new chromium drugs .5-Aminosalicylic acid (5-ASA) is identified as an active component in the therapy of inflammatory bowel disease (IBD) such as Crohn's disease and ulcerative colitis . The therapeutic action of 5-ASA is believed to be coupled to its ability to act as a free radical scavenger [3-4],acting locally on the inflamed colonic mucosa [5-7]. However, the clinical use of 5-ASA is limited, since orally administered 5-ASA is rapidly and completely absorbed from the upper gastrointestinal tract and therefore the local therapeutic effects of 5-ASA in the colon is hardly expected.In this paper, we report the synthesis of chromium(Ⅲ)5-aminosalicylate from 5-ASA and CrCl3. 6H2O.The synthesis route is as follow:The complex has been characterized by elemental analysis, IR spectra, X-ray powder diffractionand TG-DTA . They indicate that the structure is tris(5-ASA) Chromium . Experiments show that thecomplex has a good activity for supplement tiny dietary chromium, lowering blood glucose levels,lowering serum lipid levels and in creasing lean body mass .     

Zn_2SnO_4纳米材料制备及光致发光特性

以ZnO、SnO2和活性炭的混合物为原料,通过碳热还原热蒸发法无催化剂成功制备出Zn2SnO4纳米材料.借助X射线衍射仪(XRD)、拉曼光谱和扫描电子显微镜(SEM)对样品物相和形貌进行了表征,结果显示样品为面心立方结构的Zn2SnO4纳米链状棒,同时含有少量的ZnO物相.利用X射线光电子能谱(XPS)对Zn2SnO4样品表面各元素的化学状态及相互作用方式进行了测试,结果表明:样品中Zn和Sn分别是以+2价和+4价氧化态形式存在,其中Zn2p3/2电子有两个结合能,分别来自ZnO和Zn2SnO4,Zn2SnO4中Sn4+占据不同的格点位置.室温下光致发光谱(PL)结果显示,样品在紫外区域(320-450nm)和可见区域存在很强的发光带,其中紫外区域的宽发光带,经过高斯拟合可分为358和385nm两个发光峰,与同条件下制备得到的纯ZnO纳米材料发光谱比较,确认358nm发光峰是来自于Zn2SnO4的近带边复合发光.     

A New Method of Synthesis of Nanosized Boehmite (AlOOH) Powders with a Low Impurity Content

A new method of synthesis of nanosized aluminum oxyhydroxide (AlOOH, boehmite) powders has been suggested through a hydrothermal treatment of nanosized γ-Al₂O₃ powder in water and a 1.5 wt % HCl solution at different temperatures. It has been found that hydrothermal treatment in a 1.5 wt % HCl solution leads to the purification of the starting material; different treatment durations allow one to obtain boehmite particles of different shape. It has been demonstrated that a nanosized boehmite powder is obtained upon the hydrothermal treatment of a nanosized γ-Al₂O₃ in water above 80°С. The nanosized boehmite powders synthesized at different temperatures have been studied by various methods.     

InOOH hollow spheres synthesized by a simple hydrothermal reaction

Novel micrometer-sized indium oxyhydroxide (InOOH) hollow spheres were successfully synthesized via a citric acid (CA) assisted hydrothermal process. The morphology, crystal structure, and optical properties of the product were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and UV-vis diffuse reflectance spectroscopy (DRS). The optical band gap, E(g), was estimated to be 3.5 eV from the DRS spectrum, which is almost equal to that of indium oxide. Furthermore, on the basis of a series of SEM observations, phenomenological elucidation of a mechanism for the growth of the InOOH hollow spheres has been presented; key factors for the formation of the structures have been proposed.     

Direct synthesis and integration of functional nanostructures in microfluidic devices

Integration of functional nanostructures within a microfluidic device can synergize the advantages of both unique properties of nanomaterials and diverse functionalities of microfluidics. In this paper, we report a novel and simple method for the in situ synthesis and integration of ZnO nanowires by controlled hydrothermal reaction within microfluidic devices. By modulating synthesis parameters such as the seed preparation, synthesis time, and heating locations, the morphology and location of synthesized nanowires can be easily controlled. The applications of such nanostructure-integrated microfluidics for particle trapping and chemiresistive pH sensing were demonstrated.     

低维ZnO纳米材料

本文主要综述了近年来ZnO纳米材料制备领域的一些新方法,简单比较了各种方法之间的优缺点;讨论了制备不同形貌的ZnO纳米材料的影响因素,其中重点讨论了表面活性剂的作用;介绍了ZnO纳米材料的性质及其可能的应用领域;并对ZnO纳米材料的发展前景进行了展望。