不同形貌Fe3O4纳米粒子的氧化沉淀法制备与表征

用一种方法成功合成出了球体、四方体、八面体、不规则多面体、三角形和不规则颗粒等六种具有不同形貌的Fe₃O₄纳米粒子，通过扫描电子显微镜(SEM)表征了粒子形貌。试样经过X-射线衍射(XRD)表征具有尖晶石结构，且结晶良好。经震动样品磁强计(VSM)测定，各种形貌的Fe₃O₄纳米粒子都具有良好的磁性，其中八面体形貌的Fe₃O₄纳米粒子的饱和磁化强度达到86.56 emu·g^-1，剩磁为10.64 emu·g^-1，矫顽力为138 Oe。讨论了不同形貌的Fe₃O₄纳米粒子的形成机制，得出了晶核的生长环境对纳米粒子的形貌有重要影响的结论。     

焙烧温度对In2TiO5纳米带晶型结构及光催化性能的影响

以Ti(OC₄H₉)₄、In(NO₃)₃和聚乙烯吡咯烷酮(PVP-K30)为原料,采用静电纺丝技术制备了In₂TiO₅纳米带。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见漫反射光谱(UV-Vis DRS)和N₂吸附-脱附等技术对不同焙烧温度处理得到的样品进行表征,详细研究了焙烧温度对In₂TiO₅纳米带晶粒尺寸、形貌、比表面积和孔径的影响。以20 mg·L^-1的氟喹诺酮类抗生素左氧氟沙星(LEV)为目标降解物,125 W高压汞灯为光源,评价了不同焙烧温度下In₂TiO₅纳米带的光催化活性。结果表明,焙烧温度对In₂TiO₅的形貌与光催化活性有明显影响。当焙烧温度为800℃时,制备的In₂TiO₅纳米带表面光滑,其宽度为(552±58) nm、厚度约为140 nm,光催化活性最强,光照60 min,LEV的降解率可以达到95%。     

焙烧温度对In2TiO5纳米带晶型结构及光催化性能的影响

以Ti(OC₄H₉)₄、In(NO₃)₃和聚乙烯吡咯烷酮(PVP-K30)为原料,采用静电纺丝技术制备了In₂TiO₅纳米带。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见漫反射光谱(UV-Vis DRS)和N₂吸附-脱附等技术对不同焙烧温度处理得到的样品进行表征,详细研究了焙烧温度对In₂TiO₅纳米带晶粒尺寸、形貌、比表面积和孔径的影响。以20 mg·L^-1的氟喹诺酮类抗生素左氧氟沙星(LEV)为目标降解物,125 W高压汞灯为光源,评价了不同焙烧温度下In₂TiO₅纳米带的光催化活性。结果表明,焙烧温度对In₂TiO₅的形貌与光催化活性有明显影响。当焙烧温度为800℃时,制备的In₂TiO₅纳米带表面光滑,其宽度为(552±58) nm、厚度约为140 nm,光催化活性最强,光照60 min,LEV的降解率可以达到95%。     

Mn2O3纳米结构的简易合成与电化学性质

用简易的室温或水热方法制备出不同形貌的MnCO₃微结构。经600 ℃热处理后,室温制备MnCO₃转变成Mn₂O₃胶体片,而水热制备MnCO₃样品则形成多孔Mn₂O₃纳米结构。然而,室温制备MnCO₃经120 ℃热处理后形成Mn₂O₃晶相。制备样品经过XRD和SEM表征表明,热处理MnCO₃前驱物形成Mn₂O₃过程导致产物形貌与结构变化。其形成机理又通过TEM和FTIR进一步研究。Mn₂O₃纳米结构的电容性质通过循环伏安法表征,结果表明Mn₂O₃形貌与结构对其电容有重要影响。     

铟锡氧化物纳米网的微波法制备及其光催化特性研究

By using ultrasonic and chemical liquid coprecipitation, the precursor was prepared with high purity In, SnCl₄·5H₂O and urea. The In₂O₃·SnO₂ nanonets were obtained from precursor by heating in microwave oven. The powders were characterized by XRD, TEM. The analyzed results show the sample is In₂O₃·SnO₂, and In₂O₃is rhombohedral system while SnO₂ is tetragonal system. The sample is in spherical grain shape, with average granularity of 35 nm, and the mesh diameter of 10～80 nm. The sample was with fluorescence and good photocatalytic performance for degradation of organic dyestuff.     

无氨湿法制备纳米晶In2O3及表征

Preparation of In₂O₃nano-scale powders by ultrasonic and homogeneous precipitation, using metal In and urea as raw materials, was reported for the first time, while the effects of reaction temperature, the ratio of the materials and the pH etc. on the preparation was dicussed. This method can be operated and industrialized easily with very low cost． The structural properties of precursor and In₂O₃were characterized by TG-DTA, XRD, ESCA and TEM. The results show that In₂O₃produced are very pure, monophase and spherical nano-scale powders with average size of 25 nm.     

多层多孔Co3O4纳米粒子组装体的合成、表征和电化学性能研究

利用十二烷基磺酸钠(SDS)作为表面活性剂,合成了形貌化的CoC₂O₄配合物前驱物,然后在500 ℃下热分解形貌化的前驱物,得到了多层多孔Co₃O₄纳米粒子组装体。采用FESEM、TEM、HRTEM、XRD、N₂吸附脱附和Raman散射等手段对产物进行了分析和表征。低角XRD,TEM和N₂吸附脱附测试表明所得组装体具有多孔结构。常规XRD、HRTEM和Raman结果证明组装体中Co₃O₄纳米粒子建筑块结晶较好。与体相Co₃O₄晶体相比,Co₃O₄纳米粒子组装体的5个拉曼活性峰发生了明显的红移。将Co₃O₄纳米粒子组装体作为锂离子电池的正极材料进行了电化学性能测试,结果表明该组装体电极的首次放电容量为1 115 mAh·g^-1,远高于目前文献报道的Co₃O₄纳米管、纳米粒子和纳米棒电极。但是,该组装体电极的循环性能不好,有待进一步提高。     

Co3O4纳米片的制备及其电化学电容性能

以配位超分子化合物为前驱物,通过液相氧化分解得到了六方形CoOOH纳米片,进而在空气中热处理制得了Co₃O₄纳米片。利用XRD、TEM、FESEM对CoOOH和Co₃O₄纳米片的结构和形貌进行了表征。电化学测试表明,Co₃O₄纳米片电极在6 mol·L^-1 KOH溶液中表现出良好的电化学电容特性,在电流密度为1 A·g^-1其单电极比容量可达到227 F·g^-1。     

Fe2O3/Al2O3二元气凝胶合成高质量单壁纳米碳管

通过溶胶和超临界干燥方法制得了Fe₂O₃/Al₂O₃二元气凝胶，其比表面积和孔隙体积分别为246 m²·g^-1和1.89 cm³·g^-1，并具有较宽的孔径分布。以Fe₂O₃/Al₂O₃二元气凝胶作催化剂，通过甲烷催化裂解成功地合成了高质量的单壁纳米碳管。利用FESEM、TEM和HRTEM、Raman光谱等分析手段研究了反应温度对单壁纳米碳管生长的影响。结果表明在900 ℃时合成单壁纳米碳管的质量较高，并且合成的炭产物为毡状，该炭产物主要为高质量的单壁纳米碳管。     

Au/Al2O3纳米复合薄膜的制备和表征

用溶胶-凝胶法制备了Au/Al₂O₃纳米复合薄膜。利用X-射线衍射、X-射线光电子能谱、原子力显微镜以及紫外-可见光谱对薄膜的微观结构、表面形貌及光学性能进行了表征,研究表明:Au/Al₂O₃纳米复合薄膜是由纳米微晶组成的颗粒膜, 复合薄膜均匀、致密、无裂纹,Au以纳米晶核形式镶嵌于Al₂O₃基体中,纳米Au晶核的粒径为23～26nm;复合薄膜在可见光区有较强的吸收,吸收峰位置与烧结温度有关,吸收强度随烧结温度和金添加量增大而增大。     

Fabrication of Si3N4/SiC nanocomposites toughened by in-situ formed low-dimensional nanostructures

We report the fabrication of Si₃N₄/SiC nano/nano-composite reinforced by single-crystal low-dimensional nanostructures via spark plasma sintering of nanocomposite powders containing in-situ formed Si₃N₄ nanowires/nanobelts. The fabricated nanocomposite is analyzed by scanning electron microscopy, X-ray diffraction, transmission electron microscopy and selective area electron diffraction. The results show that the in-situ formed Si₃N₄ nanowires/nanobelts are uniformly distributed within the matrix. Such a nanocomposite could exhibit improved mechanical properties, due to the superior mechanical properties and uniform distribution of the nano-reinforcements.     

Formation of α-Fe2O3/FeOOH nanostructures with various morphologies by a hydrothermal route and their photocatalytic properties

A series of α-Fe₂O₃/FeOOH nanostructures with different morphologies have successfully been synthesized based on K₄[Fe(CN)₆] at 140 °C by a novel hydrothermal method. The morphology and phase of α-Fe₂O₃/FeOOH can be controlled by adjusting the reaction time. UV–vis absorption spectrum, X-ray powder diffraction, and transmission electron microscopy analyses were used to characterize the resulting products. A detailed, rational mechanism is proposed for the formation of α-Fe₂O₃/FeOOH nanostructures. The potential applications of the as-synthesized α-Fe₂O₃/FeOOH nanoparticles with different morphologies on photocatalytic decomposition of salicylic acid were also investigated.     

In2O3敏化ZnO纳米棒阵列的性能及其光电催化活性

以掺氟SnO₂ (FTO)导电玻璃为基底, 采用水热法制备了ZnO纳米棒阵列. 通过In(NO₃)₃水溶液水洗的方法, 合成了In₂O₃敏化ZnO纳米棒阵列光催化剂. 采用场发射扫描电子显微镜(FESEM), X射线能谱(EDX), X射线衍射(XRD)及紫外-可见漫反射光谱(UV-Vis DRS)对样品的形貌、结构、组成、晶相等进行一系列的表征. 以罗丹明B (RhB)为目标降解物, 探究了In₂O₃敏化ZnO 纳米棒阵列光电催化活性. 采用场诱导表面光伏技术(FISPV)研究了不同含量的In₂O₃敏化ZnO纳米棒阵列在光照射下的光生电荷行为. 结合电化学工作站检测不同样品的光电流, 随着In₂O₃敏化量的改变, 光电流和开路电压也随之改变. 并探讨了In₂O₃敏化ZnO纳米棒阵列光生电荷行为与光电催化活性之间的关系. 结果表明, 适量In₂O₃敏化的ZnO光催化剂在可见光下2 h内对罗丹明B的降解效率达到95%, 是单纯ZnO纳米棒阵列的2.4倍.     

Synthesis of Co3O4 nanostructures using a solvothermal approach

The controlled synthesis of Co₃O₄ nanostructures with morphologies of micro-spheres, nanobelts, and nanoplates was successfully achieved by a simple solvothermal method. Various comparison experiments showed that several experimental parameters, such as the reaction temperature and the concentration of NH₃·H₂O, play important roles in the morphological control of Co₃O₄ nanostructures. A lower temperature and a lower concentration of NH₃·H₂O favor spherical products with a diameter of 1–1.5 μm, whereas a higher temperature and a higher concentration of NH₃·H₂O generally lead to the formation of nanobelts with a width of 20–150 nm. In addition, Co₃O₄ hexagonal nanoplates with an edge length of about 200–300 nm are also obtained by adding surfactant CTAB. A rational mechanism is proposed for the selective formation of various morphologies. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and field-emission scanning electron microscope (FE-SEM) were used to characterize the products.     

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.     

Oriented SrFe12O19 thin films prepared by chemical solution deposition

Thin films of SrFe₁₂O₁₉ (SrM) were prepared from a solution of iron and strontium alkoxides through the chemical solution deposition method on both amorphous (glassy SiO₂), and single crystal substrates (Si(100), Si(111), Ag(111), Al₂O₃(001), MgO(111), MgAl₂O₄(111), SrTiO₃(111)) substrates. The process of crystallization was investigated by means of powder diffraction, atomic force microscopy and scanning electron microscopy. Magnetization measurements, ferromagnetic and nuclear magnetic resonance were used for evaluation of anisotropy in the films. Whilst amorphous substrates enabled growth of randomly oriented SrM phase, use of single crystal substrates resulted in samples with different degree of oriented growth. The most pronounced oriented growth was observed on SrTiO₃(111). A detailed inspection revealed that growth of SrM phase starts through the breakup of initially continuous film into isolated grains with expressive shape anisotropy and hexagonal habit. A continuous film with epitaxial relations to the substrate was produced by repeating recoating and annealing.     

Assembly of Pt nanoparticles on electrospun In2O3 nanofibers for H2S detection

In this paper, we presented a simple and effective solution route to deposit Pt nanoparticles on electrospun In₂O₃ nanofibers for H₂S gas detection. The morphology and chemical structure of the as-prepared samples were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectra (XPS). The results showed that large quantities of In₂O₃ nanofibers with diameters about from 60 to 100 nm were obtained and the surface of them was decorated with Pt nanoparticles (5–10 nm in size). The In₂O₃ nanofibers decorated by Pt nanoparticles exhibited excellent gas sensing properties to H₂S, such as high sensitivity, good selectivity and fast response at relatively low temperature.     

Self-catalyst growth of single-crystalline CaB6 nanostructures

Large-scale calcium hexaboride (CaB₆) nanostructures have been successfully fabricated with self-catalyst method using calcium (Ca) powders and boron trichloride (BCl₃) gas mixed with hydrogen and argon. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected-area electron diffraction (SAED) were used to characterize the compositions, morphologies, and structures of the samples. Our results show that the nanowires are highly single crystals elongated preferentially in the [1 1 0] direction. The growth mechanism based on the self-catalyst process is simply discussed.     

Uniform In2S3 octahedron-built microspheres: Bioinspired synthesis and optical properties

Uniform In₂S₃ octahedron-built microspheres were synthesized by using a mild hydrothermal treatment in the presence of L-glutamic acid at 180 °C. The microsphere with an average size of 5 μm was composed of interconnected octahedrons with diameters in the range from 100 to 150 nm. The products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and X-ray photoelectron spectroscopy (XPS). The synthesis of various hollow and solid sphere structures and flower structures was achieved using different amino acids. This is the first report on synthesizing In₂S₃ nanostructures using different amino acids to modulate the morphology of the final products. Primary photoluminescence studies on the prepared In₂S₃ microspheres show promising results.     

Structural aspects and defect chemistry in In2O3

The C-type rare earth structure of In₂O₃ is compared with the fluorite structure. The stability of the structure is discussed based on DTA and X-ray work and electron microscopy. Ordering of defects does not take place, so that defect chemistry can be formulated for isolated defects in nonstoichiometric In₂O₃. The influence of the incorporation of aliovalent cations into the In₂O₃ host lattice is discussed and a defect model is suggested.