Advanced Materials Research Vol. 924

Abstract: Multilayered SnO₂ hollow microspheres (MHS-SnO₂) have been successfully synthesized via a solvothermal method by using glycol-water as solvent. The morphology, composition and structure of the product have been characterized by field-emission scanning electron microscopy (FESEM) with an energy dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) with selected area electron diffraction (SAED) and X-ray diffraction (XRD). The FESEM, TEM and HRTEM images indicate that the as-prepared microspheres show multilayered structure and the wall of the hollow microspheres is composed of single crystalline nanoparticles. Study on hydrogen absorption characteristics of MHS-SnO₂ performed at 373 K shows a good absorption capacity of 0.85 wt.%.

Abstract: Nanoparticles comprising chitosan-graft-poly (methyl methacrylate) (CS-g-PMMA) copolymer were successfully synthesized in aqueous solution by using potassium diperiоdatоnickelate (Ni (IV)) as an initiator. The nanoparticles were characterized in terms of Fourier transform infrared (FTIR), dynamic light scattering (DLS) and transmission electron microscopy (TEM). The results indicated that chitosan was covalently linked to poly (methyl methacrylate) (PMMA) and the particles were uniform, spherical and well dispersed with narrow size distribution. Paclitaxel-loaded nanoparticles were prepared and in vitro release showed that these nanoparticles provided an initial burst release followed by a slowly sustained release for more than 16 days. Therefore, this process method would be used for synthesizing natural polymer graft copolymer nanoparticles with wide prospect.

Abstract: Allyl-functionalized copolymers with well-defined structure have been successfully prepared via selective reversible addition-fragmentation chain transfer (RAFT) copolymerization of styrene and allyl methacrylate possessing a higher reactive methacrylate and a lower reactive allyl. By employing a fast RAFT equilibrium, the polymerization for AMA completely occurred in methacrylate double bonds, whereas allyl double bonds remained intact and were introduced into the side-chains. GPC and ¹H NMR analyses have confirmed the high chain-end functionality of the resultant copolymer.

Abstract: New cellulose derivative CMC-Li was synthesized, and nanometer fiber composite material was applied to lithium-ion battery and coated with AQ by electrospinning. Under the protection of inert gas, modified AQ/ carbon nanofibers (CNF) /Li nanometer composite material was obtained by carbonization in 280^OC as lithium battery anode materials for the first time. The morphologies and structure performance of materials were characterized by using IR, SEM, CV and EIS, respectively. Specific capacity was increased to226.4 mAh.g^-1 after modification for the first discharge at the rate of 2C. Performance of cell with CMC-Li with the high degree of substitution (DS) was superior to that with low DS. Cellulose materials were applied to lithium battery to improve battery performance by electrospinning.

Abstract: Nonwoven fibers of cellulose triacetate (CTA) were continuously electrospun by using DMSO/chloroform co-solvent system and the size and morphology of fibers were investigated. It was found that the concentration of 8wt% CTA fibers were obtained from DMSO/chloroform with volume ratio of 1:1, 3:2, 2:1, 3:1. The average diameters of CTA fiber was decreased with decreasing chloroform content in the mixed solvent. The minimum diameter of the continuous electrospun cellulose triacetate fibers obtained in this work ranged between 210 and 880 nm.

Abstract: Two types of Au/Si-NPA samples based on different surface oxidation state were prepared by immersion method. Their surface morphology and optical absorption property were also investigated. The results showed, due to the different deposition region of Au nanoparticles, their surface morphology and structure were quite different, and their absorption curves were also different. Optical absorption property of samples prepared on aged substrate was better than those of prepared on fresh substrate, except 15 minutes samples.

Abstract: The nano-TiO2 was prepared by adding surfactant chitosan and sodium dodecyl benzene sulfonate (DBS) under hydrothermal conditions. The influence of chitosan and DBS on the crystal form and photocatalytic properties of TiO2 was discussed. Chitosan acted as the chelant in the reaction, while DBS played the function of preventing aggregation of powder and increasing the degree of crystallization. The fixed calcination temperature was 500°C. The crystallite size could reach about 40.1nm upon the addition of 1g chitosan, and the catalytic efficiency was 51.89%. The crystallite size was about 45.8nm upon the addition of 1g DBS, and the catalytic efficiency was 48.13%. The nano-TiO2 had smaller particle size when chitosan was added under the same reaction conditions.

Abstract: In this paper, α-Fe₂O₃ nanocrystals have been synthesized, using FeCl₃, oleic acid, ethanol and NaOH as raw materials by a hydrothermal method at 180°C for 10h. The samples were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) for the information of crystal category, form and size. The results showed the materials are nanocubes and side-length about 20 nm. Moreover, the properties of α-Fe₂O₃ nanocrystals as anode materials for Li-ion batteries had been studied. The first-discharge capacity is 1280 mAh g^-1, which made this material maybe one of the candidates for the negative materials.

Abstract: SrMoO₄:Eu³⁺ micro-spheres with well morphology were fabricated by a one-step and template-free ultrasonic spray pyrolysis method using strontium nitrate and ammonium molybdate as precursors. The as-prepared products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectra (PL). The XRD results indicate that all the XRD peaks can be indexed as SrMoO₄ with a pure tetragonal scheelite structure. The SEM photographs show that the sample particles are spheres with regular spherical shape. The excitation and emission spectra demonstrate that the phosphors could be excited effectively by the ultraviolet light with wavelength 394 nm or visible blue light with wavelength 466 nm, and the highest emission peak locates at 615 nm.

Abstract: Using six-ring rock (a natural mineral with good adsorption ability) as carrier, the TiO₂/six-ring rock composite was successfully synthesized by sol-gel process. The sintering temperatures and condensate return times exhibit a strong effect on the catalytic performance of the photocatalyst. X-ray diffractometer (XRD) showed that obvious diffraction peaks of anatase TiO₂ appeared when the calcination temperature is 550°C. The SEM images revealed that nanoTiO₂ has been widely loaded on the surface and pores of six-ring rock particles. Photodegradation for methyl orange (MO) exhibited that the TiO₂/six-ring rock photocatalyst is of higher photocatalytic activity than pure six-ring rock, and the maximum degradation rate can reach 75% under the optimized conditions.