Nanosized TiO2 and TiO2/SiO2 particles were prepared by hydrolysis of tetrabutyl titanate (TBOT) and tetraethyl orthosilicate (TEOS) in the TX-100 reverse microemulsion. These particles were characterized by TG-DSC, XRD, FTIR, TEM,N2 adsorption-desorption. Their photocatalytic activity was tested by degradation of methyl orange. The result shows that TiO2/SiO2 nanoparticles are with a monodispersed spherical phase and a uniform size distribution,and TiO2 particles are dispersed on the surface of SiO2. The band for Ti-O-Si vibration in FTIR was observed, the Ti-O-Si bond increased the stability of anatase TiO2, suppressed the phase transformation of titania from anatase to rutile. And due to the addition of SiO2, the average size of titania decreased from 38 nm in pure TiO2 to 5 nm in TiO2/SiO2. It was found, under UV light irradiation, TiO2/SiO2 particles showed higher activity than pure TiO2, and TiO2/SiO2(1/1) particles showed the highest photocatalytic activity on the photocatalytic decomposition of methyl orange, which was influenced by crystal structure, particle size, crystallinity and Surface area Characteristics. 相似文献
TiO2 coated SiO2 materials as anode for lithium-ion batteries were synthesized via an in situ hydrolysis of tetraethyl orthosilicate under ultrasonic irradiation using nanometer-sized TiO2 colloids as precursors. The XRD patterns indicate that the as-prepared core/shell particles remain anatase after calcining below 800 ℃. TEM observation shows that the particle size of TiO2 / SiO2 composites is ca. 200 nm, and a homogeneous SiO2 layer is coated on the surfaces of TiO2 particles. FTIR spectra demonstrate that SiO2 could have been coated on the surfaces of TiO2 particles via a chemical bonding. In addition, the first specific charge and discharge capacities of the coated particle electrode were 66.4 mAh·g-1 and 90.7 mAh·g-1, respectively, which indicates that the TiO2 / SiO2 particles are more stable than the monodispersed TiO2. Meanwhile, the new material has good lithium intercalation-deintercalation performances. 相似文献
TiO2-SiO2 nanocomposite particles were prepared in premixed H2 / Air flame, and the morphology and structure of these nanocomposites were characterized by FTIR, XRD, TEM and HRTEM. The morphology of SiO2 / TiO2 nanocomposites was different from that of pure TiO2 or SiO2 nanoparticles, and the chemical bond of Ti-O-Si was found in the nanocomposites indicating that the TiO2 / SiO2 nanocomposites were not merely a physical mixture of TiO2 and SiO2. TiO2 nanocrystalline grains with sizes of 1~2 nm were homogeneously dispersed in the amorphous SiO2 matrix when TiCl4 and SiCl4 were mixed at molecular level in the flame. The particle size and rutile content decreased with increasing of SiO2 molar ratio. 相似文献
TiO2–SiO2 composite nanoparticles were prepared by a sol–gel process. To obtain the assembly of TiO2–SiO2 composite nanoparticles, different molar ratios of Ti/Si were investigated. Polyurethane (PU)/(TiO2–SiO2) hybrid films were synthesized using the “grafting from” technique by incorporation of modified TiO2–SiO2 composite nanoparticles building blocks into PU matrix. Firstly, 3-aminopropyltriethysilane was employed to encapsulate TiO2–SiO2 composite nanoparticles’ surface. Secondly, the PU shell was tethered to the TiO2–SiO2 core surface via surface functionalized reaction. The particle size of TiO2–SiO2 composite sol was performed on dynamic light scattering, and the microstructure was characterized by X-ray diffraction and
Fourier transform infrared. Thermogravimetric analysis and transmission electron microscopy (TEM) employed to study the hybrid
films. The average particle size of the TiO2–SiO2 composite particles is about 38 nm when the molar ratio of Ti/Si reaches to1:1. The TEM image indicates that TiO2–SiO2 composite nanoparticles are well dispersed in the PU matrix. 相似文献
Optically active polyurethane/titania/silica (LPU/TiO2/SiO2) multilayered core–shell composite microspheres were prepared by the combination of titania deposition on the surface of silica spheres and subsequent polymer grafting. LPU/TiO2/SiO2 was characterized by FT-IR, UV–vis spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), SEM and TEM, and the infrared emissivity value (8–14 μm) was investigated in addition. The results indicated that titania and polyurethane had been successfully coated onto the surfaces of silica microspheres. LPU/TiO2/SiO2 exhibited clearly multilayered core–shell construction. The infrared emissivity values reduced along with the increase of covering layers thus proved that the interfacial interactions had direct influence on the infrared emissivity. Besides, LPU/TiO2/SiO2 multilayered microspheres based on the optically active polyurethane took advantages of the orderly secondary structure and strengthened interfacial synergistic actions. Consequently, it possessed the lowest infrared emissivity value. 相似文献
Two‐dimensional anatase TiO2 hollow nanoplates were firstly synthesized through a facile synthesis route by using α‐Fe2O3 nanoplates as removable templates. Two‐dimensional hollow TiO2 nanoplates with different ratios of anatase and rutile phases were obtained by adjusting the calcining temperature. The average diameters were around 600 nm, and the shell thickness was approximately 30 nm. The photocatalytic performance of TiO2 was investigated by decomposing rhodamine B under simulated sunlight. Among the TiO2 samples, the anatase TiO2 hollow nanoplates manifested a significant enhancement in the photocatalytic performances. The excellent catalytic performance can be attributed to the unique structure of the two‐dimensional anatase TiO2 hollow nanoplates, including a large surface area and increased dye–photocatalyst contact areas as well as more active sites for photodegradation. 相似文献
Summary: We demonstrate in this communication that large‐scale coaxial nanocables of polypyrrole (PPy)/TiO2 can be obtained via three steps: (1) synthesis of TiO2 nanofibers by electrospinning; (2) physical adsorption Fe3+ oxidant on the surface of TiO2 nanofibers; (3) followed by polymerization of pyrrole (from vapor) on the surface of TiO2 nanofibers. During the synthesis, the PPy formed on TiO2 nanofibers as a template and formed PPy/TiO2 coaxial nanocables. TEM image proved that PPy (20 nm thickness) covered the surface of TiO2 nanofibers. Fourier‐transform infrared (FTIR), X‐ray photoelectron spectra (XPS), and X‐ray diffraction patterns (XRD) characterized the chemical structure of the coaxial nanocables. Surface photovoltage spectroscopy (SPS) revealed the surface properties of the PPy/TiO2 coaxial nanocables.
TEM image of individual PPy/TiO2 coaxial nanocable. 相似文献
Nanoscale composite materials based on the SiO2–TiO2 system were prepared in the form of co-precipitated composites and core SiO2–shell TiO2 composites, with specific surface area 150–650 m2/g and sorption volumes 0.1–1.0 cm3/g. It is shown that variation of phase composition and morphology permits to change their structural-adsorption properties and nanocrystallites size after thermal treatment. It is discovered that co-precipitated composite materials differ from core SiO2–shell TiO2 composites by a component interaction degree. It determines the difference of the titan-containing component crystallization process and alteration of their structural-absorption properties after thermal treatment. The results of the tests of composites as photocatalysts for Rhodamine B decomposition reaction, as catalysts of Hantzsch and Biginelli reaction, and as fillers in electrorheological fluids are shown. 相似文献