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1.
Biomass charcoal-doped titanium dioxide (C/TiO 2) composites were proposed by microwave-hydrothermal and calcination method using tetrabutyl titanate as the titanium source and lignin as the carbon source. TiO 2 crystals with different morphologies could be successfully adsorbed onto the surface of biomass charcoal. These products were investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG), derivative thermogravimetric (DTG), UV–vis diffuser flection spectroscopy (UV–vis), Fourier transform infrared spectroscopy (FT-IR), and Brunauer–Emmett–Teller (BET). The photocatalytic activities of the as-obtained composites were checked under visible light irradiation. The results showed that both the microwave-hydrothermal temperature and time played an important role in the microstructure and photocatalytic activity of the samples. The rapid microwave-hydrothermal with the thermal post-treatment provides a promising route for the fabrication of biomass charcoal-doped nanocomposites materials. 相似文献
2.
In this paper, magnetic nanocomposites are synthesized by loading reduced graphene oxide (RG) with two components of nanoparticles consisting of titanium dioxide (TiO 2) and magnetite (Fe 3O 4) with varying amounts. The structural and magnetic features of the prepared composite photocatalysts were investigated by powder X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectra (UV–vis/DRS), Raman and vibrating sample magnetometer (VSM). The resulting TiO 2/magnetite reduced graphene oxide (MRGT) composite demonstrated intrinsic visible light photocatalytic activity, on degradation of tartrazine (TZ) dye from a synthetic aqueous solution. Specifically, it exhibits higher photocatalytic activity than magnetite reduced graphene oxide (MRG) and TiO 2 nanoparticles. The photocatalytic degradation of TZ dye when using MRG and TiO 2 for 3 h under visible light was 35% and 10% respectively, whereas for MRGT it was more than 95%. The higher photocatalytic efficiency of MRGT is due to the existence of reduced graphene oxide and magnetite which enhances the photocatalytic efficiency of the composite in visible light towards the degradation of harmful soluble azo dye (tartrazine). 相似文献
3.
Zirconia based nanocomposites have attracted much research attention in recent years due to their exceptional biomedicinal activities. Rhizome extracts of Corallocarpus epigaeus based ZrO 2/CuO–ZnO nanocomposite were green synthesized in a facile synthesis strategy. The nanocomposites were examined with XRD technique for their structural information and FT-IR technique for surface functional group analysis. Electron microscopic images aided to elucidate the CuO and ZnO nanoparticles decorated ZrO 2 nanostructures. UV–vis absorption spectroscopic studies of the nanocomposite revealed the characteristic UV absorption of ZrO 2 and enhanced visible region absorption for the incorporated nanoparticles. Antibacterial and antifungal studies indicated enhanced activity of nanocomposites over the pristine zirconia nanoparticles. ZrO 2/CuO–ZnO nanocomposite had exhibited about 75% of α-amylase inhibition activity, whereas pristine ZrO 2 nanoparticles had exhibited only 57% suggesting the worthwhile application in the antidiabetic activity of the nanocomposite. 相似文献
4.
In this study, the goal was the preparation, characterization, and surface morphology of poly(amide-imide)/TiO 2-citric acid nanocomposites (PAI/TiO 2-CA NCs). Owing to the high surface energy and tendency for agglomeration, the surface of TiO 2 nanoparticles was modified with citric acid. Then poly(amide-imide) was synthesized by direct polycondensation reaction of N,N′-(pyromellitoyl)-bis-L-leucine diacid with 4,4′-diaminodiphenylmethane by triphenyl phosphite and tetra- n-butylammonium bromide as a green medium. The attained polymer and modified TiO 2 nanoparticles were used to prepare PAI/TiO 2-CA NCs through ultrasonic irradiation. The resulting PAI/TiO 2-CA NC was characterized with FT-IR spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis. 相似文献
5.
Pure and silver doped nanoparticles of titanium dioxide (TiO 2) was prepared using novel, modified sol–gel method. The samples were characterized by transmission electron microscopy, X-ray
diffraction, N 2 adsorption measurement, atomic absorption spectroscopy (AAS), UV–vis spectroscopy (UV–vis). The antibacterial activity of
the prepared samples was indicated by minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC)
values according to the reference methods of Clinical and Laboratory Standards Institute for the determination of MIC of aerobic
bacteria by broth microdilution. The results showed very good antibacterial activity of silver nanoforms to bacteria strains:
Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli and Klebsiella pneumoniae. The sensitivity of the tested bacteria to silver nanoforms depends on the crystalline form of the carrier—TiO 2, its surface area, porosity, the content of silver, its particle size and oxidation state. The originality of this work is
the synthesis of novel type of nanocomposites TiO 2 doped with silver and determination its excellent antibacterial activity. 相似文献
6.
This study focused on the fabrication of poly(n-butyl methacrylate) (PBMA) nanocomposites with various concentrations of cerium-doped titanium dioxide (Ce–TiO2) nanoparticles via in situ polymerization technique. The structural characterization and the material properties of all the composites were analyzed by UV–visible, FTIR, XRD, SEM, DSC, TG, and tensile strength measurements. The UV–visible and FTIR studies confirmed the effective inclusion of Ce–TiO2 nanoparticles into the PBMA matrix. The change in amorphous morphology of PBMA to a crystalline structure was observed from the XRD pattern. The SEM morphology revealed the attachment of nanoparticles in the polymer matrix. The inclusion of Ce–TiO2 nanoparticles enhanced the glass transition temperature, and thermal stability of the PBMA matrix was revealed from DSC and TG, respectively. The tensile strength of PBMA was greatly enhanced by the addition of Ce–TiO2 nanoparticles. The AC conductivity, dielectric constant, and dielectric loss studies were also performed in the frequency range 102–106 Hz, and it was observed that addition of Ce–TiO2 nanoparticles greatly enhanced the electrical properties of PBMA. The change in dielectric constant with the addition of nanoparticles was correlated with a theoretical modeling study. This work also extended to study the role of Ce–TiO2 nanoparticles in the reinforcing mechanism of the nanocomposite by comparing the actual tensile strength of the composite with different theoretical modeling. The high dielectric constant and tensile strength of composite are beneficial in designing lightweight and highly efficient nanoelectronic materials based on the family of polybutyl acrylates. 相似文献
7.
Nano-sized rod-like titanium dioxide (TiO2) filled rigid poly(vinyl chloride) (PVC) nanocomposites were prepared by using injection-molding method. Vicat, Charpy impact and tensile tests as well as thermogravimetric and dynamic mechanical analyses were used to characterize the structure and properties of the nanocomposites. The results showed that nano-TiO2 could improve Vicat softening temperature and also improve thermal stability of PVC during the stages of dehydrochlorination and formation of carbonaceous conjugated polyene sequences, which can be ascribed to restriction of the nanoparticles on the segmental relaxation as being evidenced by raises in glass transition and β-relaxation temperatures of PVC upon filling TiO2. Addition of TiO2 nanoparticles less than 40 phr (parts per hundreds of resin) could significantly improve impact strength of the composites while the TiO2 agglomeration at high contents leads to a reduction in impact toughness. 相似文献
8.
Titania nano‐sized particles were treated by various amounts of tetraethyl orthosilicate precursor. The extent of grafting was characterized using Fourier transform infrared (FTIR) and ultraviolet‐visible (UV‐Vis) spectroscopy techniques, thermal gravimetric analysis, X‐ray fluorescence and zeta potential measurements. Sedimentation behaviour of titanium dioxide (TiO 2) nanoparticles in aqueous solutions was evaluated visually and using a separation analyser. Photocatalytic activity of nanoparticles was studied by photo‐activated degradation reaction of Rhodamine B dyestuff in aqueous solutions. The results showed that grafted particles had acquired enhanced dispersion stability and lower photocatalytic activity in aqueous solutions. Untreated TiO 2 dispersions settled rapidly and sedimentation completed within 24 h through the coagulation mechanism, whereas that of the silica‐treated nanoparticles, depending on the silica content, showed different degrees of stability by flocculation mechanism. Photodebleaching of Rhodamine B in the presence of treated nanoparticles is evident by weaker intensity of UV absorption peak of 554 nm due to lowering concentration of Rhodamine B accompanied with the blue shift in UV absorption peaks. However, untreated TiO 2 nanoparticles showed only weaker intensity of UV absorption peak. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
9.
In this work, the structural and optical properties of titanium dioxide (TiO 2) nanopowders are studied. The TiO 2 nanoparticles were synthesized by complexing sol–gel process and effect of complexing agents on transition of the anatase phase to rutile phase during the heat treatment have been investigated. In addition, we have studied the grain size of TiO 2 powders and their dependence on the type of complexing agent. The analysis of the XRD patterns, FT-IR and UV–Vis spectroscopy, BET surface area and TEM images show that the synthesis of nanoparticles with acetyl acetone (AcAc) as complexing agent yielded the smallest size of nanoparticles about 22–35 nm. Our results indicate that with increasing the calcinating temperature, the size of the nanoparticles is increased and the energy gap reduced, too. Also, the optical band gap was obtained in the range of 3.4–4.1 and 3.06–3.74 eV for anatase and rutile phases, respectively. 相似文献
10.
Functional nanostructures of self‐assembled block copolymers (BCPs) incorporated with various inorganic nanomaterials have received considerable attention on account of their many potential applications. Here we demonstrate the two‐dimensional self‐assembly of anisotropic titanium dioxide (TiO 2) nanocrystals (NCs) and metal nanoparticles (NPs) directed by monolayered poly(styrene)‐ block‐poly(4‐vinylpyridine) (PS‐ b‐P4VP) copolymer inverse micelles. The independent position‐selective assembly of TiO 2 NCs and silver nanoparticles (AgNPs) preferentially in the intermicelle corona regions and the core of micelles, respectively, for instance, was accomplished by spin‐coating a mixture solution of PS‐ b‐P4VP and ex situ synthesized TiO 2 NCs, followed by the reduction of Ag salts coordinated in the cores of micelles into AgNPs. Hydrophobic TiO 2 NCs with a diameter and length of approximately 3 nm and 20–30 nm, respectively, were preferentially sequestered in the intermicelle nonpolar PS corona regions energetically favorable with the minimum entropic packing penalty. Subsequent high‐temperature annealing at 550 °C not only effectively removed the block copolymer but also transformed the TiO 2 NCs into connected nanoparticles, thus leading to a two‐dimensionally ordered TiO 2 network in which AgNPs were also self‐organized. The enhanced photocatalytic activity of the AgNP‐decorated TiO 2 networks by approximately 27 and 44 % over that of Ag‐free TiO 2 networks and randomly deposited TiO 2 nanoparticles, respectively, was confirmed by the UV degradation property of methylene blue. 相似文献
11.
Cobalt doped titania nanoparticles were synthesized by sol-gel method using titanium(IV) isopropoxide and cobalt nitrate as precursors. X-Ray diffraction (XRD) results showed that titania and Co/TiO 2 nanoparticles only include anatase phase. The framework substitution of Co in TiO 2 nanoparticles was established by XRD, scanning electron microscopy equipped with energy dispersive X-ray microanalysis (SEM-EDX) and Fourier transform infrared (FT-IR) techniques. Transmission electron microscopy (TEM) images confirmed the nanocrystalline nature of Co/TiO 2. The increase of cobalt doping enhanced “red-shift” in the UV-Vis absorption spectra. The dopant suppresses the growth of TiO 2 grains, agglomerates them and shifts the band absorption of TiO 2 from ultraviolet (UV) to visible region. The photocatalytic activity of samples was tested for degradation of methyl orange (MO) solutions. Although the photocatalytic activity of undoped TiO 2 was found to be higher than that of Co/TiO 2 under UV irradiation, the presence of 0.5% Co dopant in TiO 2 resulted in a catalyst with the highest activity under visible irradiation. 相似文献
12.
Three-dimensional (3D) hierarchical porous TiO 2/InVO 4 nanocomposites were fabricated by loading TiO 2 nanoparticles on the surface of porous InVO 4 microspheres. X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis spectroscopy and photoluminescence spectroscopy (PL) were adopted to analyze the structure–property relationship of samples. The results show that the surface of as-prepared TiO 2/InVO 4 nanocomposites are composed of uniformly interconnected bi-phase nanocrystals, forming a close interface between these two components, which is favorable for the highly efficient interparticle electron transfer to achieve enhanced photocatalytic properties. However, the adsorption ability is decreased due to the loading of TiO 2 nanoparticles on the surface of InVO 4. Therefore, under the joint action of these factors, the TiO 2/InVO 4 nanocomposites achieve the best photocatalytic activity when the mole ratio of In:Ti reaches 4:1, and the visible-light photocatalytic activity is about as 3.3 times high as that of pure InVO 4 without modification. 相似文献
13.
The objective of the study is to formulate exclusive block copolymer (BCP) nanocomposites by dispersing bcp end‐grafted nanoparticles (bcp‐ g‐nps) of PMMA‐ b‐PS‐ g‐TiO 2 within PS‐ b‐PMMA matrix. PMMA‐ b‐PS‐ g‐TiO 2 is synthesized using a “grafting‐to” approach and characterized by XPS and TGA to establish that the copolymer chains were bonded to NPs. Good dispersion of bcp‐ g‐nps in PMMA and PS‐PMMA bcp films is observed, in contrast to poor dispersion in PS films. In PS‐PMMA films, the compatible and identical bcp nature of the end‐grafted polymer, and large NP size caused it to span across entire PS‐PMMA domains. Poor and good dispersion in PS and PMMA matrices, respectively, can be rationalized by the fact that NPs interactions are driven by the PMMA at the outer corona of the bcp‐ g‐nps. Developing bcp‐ g‐nps as a strategic route to preparation of highly dispersed high permittivity NPs like titanium dioxide (TiO 2) in bcp matrix can have important ramifications for energy storage devices. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 468–478 相似文献
14.
Abstract Lecithin liposomes were studied by transmission electron microscopy (TEM), selected‐area electron diffraction (SAED), IR, and GC‐MS. Results indicate that titanium dioxide (TiO 2) nanoparticles can gain access into lecithin liposomes during sonication and the lecithin liposomes can be effectively decomposed upon illumination with near‐UV light. 相似文献
15.
In this paper, poly(methyl methacrylate‐co‐sodium sulfopropyl lauryl maleate‐co‐2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxylpropoxy) benzophenone)/TiO 2 (i.e., poly(MMA‐co‐M12‐co‐BPMA)/TiO 2) composite particles were prepared by ultrasonically initiated emulsion polymerization. To study the dispersion and UV‐stability of the composite particles, laser diffraction particle size analyzer (LDPSA), ultraviolet‐visible absorption spectroscopy (UV‐vis), UV‐vis diffuse reflectance spectroscopy (DRS), differential scanning calorimeter (DSC), and the weight loss measurement were used. The results indicate that the dispersion of the poly(MMA‐co‐M12‐co‐BPMA)/TiO 2 composite particles prepared by ultrasonically initiated emulsion polymerization is good. And the composite particles can absorb UV light; the ultraviolet absorption strength of poly(MMA‐co‐M12‐co‐BPMA) grafted onto the surface of TiO 2 has not changed after UV irradiation while that of PMMA changed significantly. The UV absorption strength, weight loss, and Tg changes are in the order PMMA> poly(MMA‐co‐M12‐co‐BPMA) >PMMA grafted onto TiO 2> poly(MMA‐co‐M12‐co‐BPMA) grafted onto TiO 2. These results show that the ultrasonically initiated emulsion polymerization will enhance the UV stability of composite particles, and the UV‐stability of PMMA can be enhanced by the introduction of the organic UV‐stabilizer BPMA and the inorganic UV‐stabilizer titanium dioxide into the PMMA chains by covalent bond, and the effect of the BPMA and the TiO 2 used together is better than that used, respectively. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
16.
Surface of TiO2 nanoparticles was modified with the in situ chemical oxidative polymerization of aniline. Polyaniline modified TiO2 nanoparticles (PANI-TiO2 ) were characterized with the FT-IR, XRD, SEM and TEM techniques. Results confirmed that PANI was grafted successfully on the surface of TiO2 nanoparticles, therefore agglomeration of nanoparticles decreased dramatically. Polyvinyl chloride nanocomposites filled with 1 wt% 5 wt% of PANI-TiO2 and TiO2 nanoparticles were prepared via the solution blending method. PVC nanocomposites were analyzed with FT-IR, XRD, SEM, TG/DTA, DSC and tensile test techniques. Effect of PANI as surface modifier of nanoparticles was discussed according to the final properties of PVC nanocomposites. Results demonstrated that deposition of PANI on the surface of TiO2 nanoparticles improved the interfacial adhesion between the constituents of nanocomposites, which resulted in better dispersion of nanoparticles in the PVC matrix. Also PVC/PANI-TiO2 nanocomposites showed higher thermal resistance, tensile strength and Young’s modulus compared to those of unfilled PVC and PVC/TiO2 nanocomposites. 相似文献
17.
Mesoporous RuO 2–TiO 2 nanocomposites at different RuO 2 concentrations (0–10 wt %) are prepared through a simple one‐step sol–gel reaction of tetrabutyl orthotitanate with ruthenium(III) acetylacetonate in the presence of an F127 triblock copolymer as structure‐directing agent. The thus‐formed RuO 2–TiO 2 network gels are calcined at 450 °C for 4 h leading to mesoporous RuO 2–TiO 2 nanocomposites. The photocatalytic CH 3OH oxidation to HCHO is chosen as the test reaction to examine the photocatalytic activity of the mesoporous RuO 2–TiO 2 nanocomposites under UV and visible light. The photooxidation of CH 3OH is substantially affected by the loading amount and the degree of dispersion of RuO 2 particles onto the TiO 2, which indicates the exclusive effect of the RuO 2 nanoparticles on this photocatalytic reaction under visible light. The measured photonic efficiency ξ=0.53 % of 0.5 wt % RuO 2–TiO 2 nanocomposite for CH 3OH oxidation is maximal and the further increase of RuO 2 loading up to 10 wt % gradually decreases this value. The cause of the visible‐light photocatalytic behavior is the incorporation of small amounts of Ru 4+ into the anatase lattice. On the other hand, under UV light, undoped TiO 2 shows a very good photonic efficiency, which is more than three times that for commercial photocatalyst, P‐25 (Evonik–Degussa); however, addition of RuO 2 suppresses the photonic efficiency of TiO 2. The proposed reaction mechanism based on the observed behavior of RuO 2–TiO 2 photocatalysts under UV and visible light is explored. 相似文献
18.
Photocatalytic degradation of polyhydroxybutyrate (PHB) polymeric films (30 μm thickness) containing different concentrations of titanium dioxide (TiO2) nanoparticles under ultraviolet (UV) irradiation (λmax = 313 nm) has been studied. The activity of TiO2 (0.001-0.005%) as a photocatalyst was determined by monitoring various functional group indices, weight loss in polymeric films and photodegradation rate constant (k
d) with irradiation time. Photodegradation was found to be highly dependent on the TiO2 nanoparticles concentration and the UV irradiation time. The rate of PHB sample photodegradation was highest when the concentration of TiO2 was 0.005% (by weight) and lowest when its concentration was 0.001%. 相似文献
19.
In this paper, we report on the synthesis, characterization, and electrochemical properties of a compact titanium dioxide layer as well as its application in dye-sensitized solar cells (DSCs). The compact TiO 2 layer, which was prepared via a facile approach by the hydrolysis of TiCl 4 aqueous solution, has been characterized by XRD, SEM, UV–vis absorption spectroscopy, voltammetry, and electrochemical impedance spectroscopy (EIS). Experimental results show that the compact TiO 2 layer with the thickness of about 100 nm is composed of anatase-phase nanoparticles with the particle size of 10–15 nm. Impedance measurements display that the compact layer of TiO 2 can prevent the back reaction of electrons with tri-iodide ions under low applied potentials, increase the open circuit voltage ( Voc) and fill factor (FF), and finally improve the conversion efficiency ( η) for the DSCs from 7.5 to 8.1%. 相似文献
20.
In the present study, poly(vinyl chloride)/titanium dioxide (PVC/TiO 2) nanocomposite films containing different amounts of synthesized TiO 2 nanoparticles and commercial rutile powder were irradiated for 5112 hr, under exposure of artificial ultraviolet and visible lights in three different intensities. The rate of degradation was determined by using weight loss data and was found to follow a pseudo‐first order kinetic model. To determine the overall rate constant of degradation, k, a possible mechanism of the photodegradation was considered. The rate equation demonstrated k as a function of TiO 2 concentration and irradiation intensity at each wavelength. The overall rate constant of PVC/TiO 2 samples were calculated to be varied in the range of 6–16 × 10 ?7 hr ?1, at all investigated conditions. The kinetic study represented that by adding synthesized TiO 2 nanoparticles, even at low content, and with increasing their concentration, the photodegradation rate of nanocomposites decreased considerably compared with the composite samples. Likewise, by adding nanoparticles, a significant increase in the nanocomposites lifetime was achieved. The effect of irradiation intensity was investigated according to the reciprocity law experiments, and it was found that photodegradation occurred in two regimes with respect to irradiation intensity. The calculated overall rate constants were validated by the experimental data. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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