Abstract: The parallel Pt nanowires with highly ordered array and the length more than a dozen micrometers were prepared by the direct current electro-deposition in porous anodic aluminum oxide (AAO) templates. The deposition was performed in a aqueous solution of the Pt (NO2)2(NH3)2 composite electrolyte. The images and structure of Pt nanowire arrays were obtained by field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM), respectively. Selected area electron diffraction (SAED) are employed to study the crystalline morphology of Pt nanowire arrays. The relationship between the nanowires length and electro-deposition time was discussed. Their growth speed is about 0.5μm/h. The TEM micrographs show that these nanowires have uniform diameter of approximate 55nm. SAED pattern reveals that the Pt nanowire has a polycrystalline structure.
Abstract: Different mass concentrations of Al2O3, SiO2, CuO nanofluids were made by using two-step method with the three types of base fluids deionized water, ethanol and ethylene glyco. The suspension stability of nanofluids and its effect by adding anion and cation surfactants through sedimentation method were studied. The results show that ehylene glycol is as the base fluid, the suspension stability of nanofluids with DW as the base fluid is worst. The suspension stability of Al2O3, SiO2, CuO nanofluids is significantly improved by addition of appropriate dosage of adding anion and cation surfactants for different base fluids. The effect of HTAB is better than that of SDBS.
Abstract: The amino-functionalized graphene/polyaniline nanocomposites (AGNS/PANI) were fabricated through in-situ chemical oxidative polymerization of aniline in the presence of amino-functionalized graphene sheets (AGNS). FTIR, UV-vis spectroscopy analyses revealed that aminophenyl groups covalently bound to the basal plane of graphene via a diazonium addition, and the polyaniline chains grafted to graphene sheets. The FE-SEM images show that PANI nanorods aligned vertically on the surface of graphene. The AGNS/PANI nanocomposite exhibits excellent electrochemical performance for supercapacitor electrode materials.
Abstract: Mg-doped TiO2 mesoporous nanomaterial with high-efficiency solar photoelectric conversion was successfully prepared by a solid-state reaction using cetyltrimethyl ammonium bromide as a template agent. As-prepared Mg-TiO2 nanomaterials are characterized with XRD、SEM, UV-Vis, XPS, BET and Raman spectroscopy. It was found that magnesium as Mg2+ incorporates into the framework of TiO2 by isomorphous replacement with content of 2.36%. The Mg-TiO2 nanoparticles are anatase phase with particle size of 10-24nm. The rod-like nanoparticles have specific surface area of 104.5m2 /g and pore-diameter distribution centre of 5.1 nm. The surface of Mg-TiO2 material with stretching vibrational peak at 1105cm−1 is assignable to the Mg-O-Ti bond. Furthermore, the UV–vis displays that the absorption region of mesoporous Mg-TiO2 powder shifts to 405nm, and the absorption intensity of the visible-light region is enhancement. At 20oC, pH = 6.8, c0 = 50 mg/L, within 150 min, the rule of pseudo-second-order reaction and the degradation rate of thiophanate methyl of 57% and 91.8% corresponding visible-light irradiation and ultraviolet irradiation are obtained for the Mg-TiO2 nanomaterial. But it is poor to photodegradation of thiophanate methyl for P25-TiO2, and it keeps to the rule of pseudo-first-order reaction.
Abstract: (Pr0.25Nd0.75)10-xDyxFe82Co2B6(x=0~0.3) ribbons were prepared by melt spinning at 25m/s and subsequent annealing. The effect of Dy content on the microstructure and magnetic properties of the ribbons has been investigated by X-ray diffractometer (XRD), scanning electronic microscope (SEM) and vibrating sample magnetometer (VSM). The magnetic properties related to the Dy content were characterized. Intrinsic coercivity of 598kA/m, remanence of 0.58T, and the maximum energy product (BH)max of 43kJ/m3 were achieved in (Pr0.25Nd0.75)9.8Dy0.2Fe82Co2B6 after annealing at 700°C for 10 minutes.
Abstract: Using patterned conductive and insulating collection devices, fibrous patterns from polyvinyl pyrrolidone were fabricated by electrospinning. Considering that the electrospun fibers tend to deposit along the direction of electric field line, when conductive patterned template is used as collector during electrospinning, the as-spun fibers tend to assemble onto the conductive grids, whereas the dropping fibers prefer to avoid insulation grid by concentrating toward the surface of the Al foil when an insulating grid based on Al foil is used as collector.
Abstract: 1D or 3D nanoZnO crystals were prepared in diethylene glycol (DEG) via solvothermal process without surfactants at 160oC. Zinc acetate dihydrate was elected as zinc source, while water, sodium hydroxide, or ammonia solution was respectively as assistant agents. The morphologies of the products were characterized by field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). With a certain content of water or sodium hydroxide, 1D ZnO nanorods were gained, having diameters of 20-90 nm and lengths of 0.04-1.8μm. With a certain content of ammonia solution, 3D shiitake-like ZnO hierarchical structures were gained. The pileus of shiitake structure composes of nanorods with diameters of 35-40 nm, while the stipe composes of one hexagonal rod with diameters of 250-350nm, or many hexagonal rods with diameters of 100-200nm. The morphology and size could be regulated by changing the amount of water, NaOH, or ammonia solution. Solvothermal process in high-viscosity solvent may provide a facile method for preparing nanomaterials.
Abstract: In this paper, TiO2/diatomite and Ce-TiO2/diatomite were prepared by sol-gel method in order to improve the spectrum responding range and its photocatalytic effect. The obtained samples were characterized by means of X-ray Diffractometer (XRD), Scanning Electron Microscope (SEM), Infrared Absorption Spectroscopy (FT-IR) and so on, and the photocatalytic activity was evaluated by methylene blue degradation. The heat stability of TiO2/diatomite was improved by Ce-doped; TiO2 was successfully loaded on diatomite through physical and chemical action. The de-coloring ratio of methylene blue of the two composite materials were similar under UV light, Ce-TiO2/diatomite was higher under visible light, it reached to 80%, and it kept 65% after the five times repeated using of Ce-TiO2/diatomite.
Abstract: A bulk casting ingot (Ø70 × 150mm) of CoCrFeNiTi0.5 high entropy alloy was prepared by vacuum medium frequency induction melting. The samples from the ingot were aged for 12h in the temperature range of 900-1100°C and then quenched in water to investigate the effect of aging temperature on the microstructure and hardness of CoCrFeNiTi0.5 alloy. The crystalline structure of as-cast CoCrFeNiTi0.5 alloy consisted of the principal face-centered cubic (FCC) dendrite phase plus (Ni, Ti)-rich R phase, (Fe, Cr)-rich σ phase, (Co, Ti)-rich Laves phase within the inter-dendrite area. The dendrite contained approximately equivalent amount of Co, Cr, Fe, Ni and a smaller amount of Ti element. After aging treatment in the temperature range of 900-1000°C, the (Co, Ti)-rich phase disappeared while the amount of (Ni, Ti)-rich phase and (Fe, Cr)-rich phase increased. But the volume fraction of FCC dendrite phase increased and the intermetallic phases decreased after aging at 1100°C. The micro-hardness and the macro-hardness of the as-cast CoCrFeNiTi0.5 alloy were HV616.8 and HRC52, respectively. After heat treatment at 1000°C, the micro-hardness and macro-hardness decreased from HV616.8 to HV386.8 and from HRC52 to HRC42.7, respectively.