Silver nanoparticles doped in polyvinyl alcohol (AgNps/PVA) were synthesized via polymer-promoted reductive reaction of AgNO3 and PVA under time-dependent exposure to UV radiation. The AgNps/PVA composites were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction, UV–Vis spectroscopy, and transmission electron microscopy to describe the structure, nuclearity, and distribution of Ag Nps within the PVA matrix. The UV–Vis spectrum of AgNps/PVA exhibited a broad surface plasmon absorption around 425–443 nm which originated from the formation of Ag NPs. Surface analysis by XPS indicated that the Ag NPs were grown solely on the PVA surface at UV exposure time of 2 h (2.0AgNPs/PVA). Increasing the UV exposure time to 4 h will cause the transformation of metallic nanosilver to oxidized nanosilver. UV–Vis absorption spectra were in situ recorded to follow the synthesis of Prussian blue (PB) on 2.0AgNPs/PVA (PB@2.0AgNPs/PVA). The colloidal dispersion of 2.0AgNPs/PVA in an acidic medium containing free Fe(III) ions and potassium hexacyanoferrate(III) revealed an additional band centered at 720 nm due to the intermetal charge-transfer absorbance of the polymeric Fe(II)-C-N-Fe(III) of the PB@2.0AgNPs/PVA nanocomposite. Control experiments were shown to involve a spontaneous electron transfer reaction between 2.0AgNPs/PVA and Fe(III) ions, with a concomitant decomposition of hexacyanoferrate(III) and formation of PB was observed. Moreover, IR gave clear cut evidence for the synthesis of PB@2.0AgNPs/PVA from the appearance of a band for the cyano group at 2090 cm?1. 相似文献
The objective of this paper is investigating the effect of different localizations of titanium dioxide (TiO2) and hexagonal boron nitride (hBN) nanoparticles in the poly(lactic acid) (PLA)/poly(ε-caprolactone) (PCL) blends on the ultraviolet (UV) blocking, infrared reflection (NIR), and thermal conductivity of the nanocomposites for the fabrication of bionanocomposites with high performance. Transmission electron microscopy images demonstrated that the different mixing sequences induced different nanoparticle localization in the immiscible PCL/PLA blend. These different localizations yielded differences in the properties of the hybrid quaternary nanocomposite. When the nanoparticles had different localizations, TiO2 at the interface and hBN in the PCL phase, the thermal conductivity was 0.86 Wm−1 K−1, 100% of UV radiation (λ = 300 nm) was blocked and 74% of NIR radiation was reflected. This nanocomposite has a strong potential for application as a multifunctional biodegradable film for agriculture, capable of absorbing UV radiation, reflecting NIR radiation, and conducting thermal energy. 相似文献
Zinc zirconate nanopowder (ZZN) photocatalyst was prepared by sol–gel method using zinc acetate and zirconium acetylacetonate as precursors. The optimal calcination temperature was 800 °C and ZnZrO3 phase was formed. The structural and morphology properties of the nanocomposite were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDAX) and ultraviolet visible diffuse reflectance (UV-DRS). The SEM observation for ZZN showed the average grain size of 26 nm. UV–vis diffuse reflectance spectra (DRS) of the nanocomposite showed an absorption edge at 355 nm. The catalytic activity of ZZN was investigated by degradation of Tertrodirect Light Blue (TLB) dye in water using UV–vis spectroscopy (UV–vis) with an initial concentration of 20 mg/L dye. The influence of the catalyst concentration, time of irradiation and pH on photodegradation of dye was investigated. The results showed that degradation of TLB dye can be conducted in the photocatalytic process. Accordingly, a degradation of more than 97% of dye was achieved by applying the optimal operational parameters with 30 mg/L of catalyst, pH 9 at 1 h irradiation. 相似文献
Nonisothermal crystallization kinetics and properties of poly(vinyl alcohol)/octasilane polyhedral oligomeric silsesquioxanes nanocomposite were investigated by differential scanning calorimetry and compared with pure poly(vinyl alcohol). The effects of octasilane polyhedral oligomeric silsesquioxanes content and cooling rate on the degree of crystallinity (Xc), crystallization half time (t1/2), Ozawa exponent (m), and Mo kinetics parameters were studied. The role of thermal treatment on the morphology and structure of the samples was studied by X-ray diffraction and scanning electron microscopy analyses. UV–visible analysis was used to show the polyhedral oligomeric silsesquioxanes effect on the nanocomposite structure. Electrochemical impedance spectroscopy analysis demonstrated that the best conductivity was for the nanocomposite with 1 wt% of octasilane polyhedral oligomeric silsesquioxanes. 相似文献
Nano-silver/poly(2-acrylamido-2-methylpropanesulfonic acid (AMPS)-methyl methacrylate (MMA)) [P(AMPS-co-MMA)]composite materials
were prepared with the silver nitrate solution containing AMPS and MMA monomers without initiator or reducer, in which Ag+ ion was reduced to nanosilver particles and the monomers were copolymerized by ultrasonic simultaneously. The microstructure
of the nanocomposite materials was characterized by means of the transmission electron microscope (TEM), X-ray photoelectron
spectroscopy (XPS), Fourier transform infrared (FT-IR), UV-Vis and fluorescence spectrometer. The nanosilver particles were
homogeneously dispersed in polymer matrix and the size of particles is in the range of 5~15 nm, the size and distribution
of nano silver particles had something to do with ultrasonic time. Spectrum of FT-IR, UV-Vis and fluorescence were indicated
that there is chemical action between namo-Ag and special group attached to the copolymer. X-ray photoelectron spectroscopy
(XPS) was proved that the interaction between nano silver and the functional group attached to copolymer is of coordination.
It is concluded that there is a kind of interaction phenomena of nanometal silver with effective polymer matrix in the nanocomposite
materials. 相似文献
In this work, the effect of a new nanocomposite material on the photodegradation of methylene blue is demonstrated. The nanocomposite is synthesized by the combination of cupric oxide (CuO) with graphene nanoplatelets (GNPs) and characterized by XRD, FE-SEM, FTIR, Raman, and UV–vis spectroscopy. Interestingly, the inclusion of GNPs with CuO enhances the photocatalytic properties of nanocomposite without tweaking inherent properties such as the conductive nature of GNPs. Within 80 min of exposure to the solar light, a 99.44% photodegradation of methylene blue is achieved, which is much better than using CuO alone, for which the degradation is only 75%. The much-improved photocatalytic performance of the nanocomposite is a consequence of low bandgap energy of GCuO as well as the conducting nature of GNPs, that causes fast photo excitation of electrons and lengthens the recombination lifetime of charge carriers respectively. 相似文献
In this research, novel ternary Ag/αFe2O3-rGO nanocomposites with various contents of GO were synthesized via a facile one-pot hydrothermal method. Ag/αFe2O3-rGO nanocomposites were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectrometer (EDX), photoluminescence (PL) spectroscopy, and Fourier transform infrared (FTIR). The results showed that hematite nanoparticles and Ag nanoparticles were well decorated on the graphene surface. Photocatalytic activity of Ag/αFe2O3-rGO ternary nanocomposites and pure Ag/αFe2O3 was investigated for photodegradation of Congo red dye solution as a model pollutant under UV light irradiation. The ternary nanocomposite with 1.8?mg/ml GO aqueous solution concentration shows higher degradation efficiency under UV light irradiation than the pure Ag/αFe2O3 and the nanocomposites with other GO aqueous solution concentrations. It was observed that the adsorption of the dyes on the nanocomposites surface is dependent on the graphene content due to a decrease in the recombination rate, particles size, and increase charge carrier transfer. The results show that the Ag/αFe2O3-rGO nanocomposite can be used as an excellent photocatalytic material for degradation of Congo red dye in wastewater. A possible photocatalytic mechanism was proposed for degradation of Congo red dye. 相似文献
The present work is focused on the preparation of hybrid ZnO/TiO2/Ag2O nanocomposite for enhanced photocatalytic activity. The resultant samples are characterized by using XRD, SEM, EDX, HR-TEM, UV-DRS, BET and XPS techniques. X-ray diffraction analysis indicates the co-existence of wurtzite, anatase and cubic phases in ZnO/TiO2/Ag2O nanocomposite. The band gap energy value of the photocatalyst is 3.39 eV, which has been evidenced from UV–visible diffuse reflectance spectroscopy measurements. Photocatalytic degradation of methylene blue dye has been investigated by using UV–visible spectrophotometer. From the result, it has been concluded that ZnO/TiO2/Ag2O nanocomposite has proven to be an efficient photocatalyst under UV irradiation when compared to that of mono and binary oxide systems. Further, the possible photodegradation mechanism is proposed to support the enhancement of photocatalytic activity towards degradation of dyes. 相似文献
The use of polymeric films incorporated with zeolite-TiO2 composites associated with UV radiation can be an alternative in the removal of volatile organic compounds (VOCs) through the adsorption and photodegradation processes. This study produced poly(lactic acid) (PLA) films incorporated with 13× zeolite, TiO2, and 13×-TiO2 zeolite composite to remove n-butanol and evaluate the by-products generated in the process. The results showed that 13× zeolite and TiO2 added individually or as a composite to PLA, gave the polymer matrix a significant increase in the removal capacity of n-butanol. The best performance was presented by the zeolite-TiO2, composite, confirming a synergistic effect. However, the formation of CO and CO2 exceeded the expected values, with the verification that the polymeric matrix underwent photodegradation action by TiO2. The polymeric film only containing zeolite is the most suitable for the removal of VOCs, as it did not present degradation of the PLA, generating a lower concentration of by-products. 相似文献
PLA/PBAT blends and PLA/PBAT/MWNT nanocomposite systems were prepared via a melt mixing process to examine their thermal and rheological properties. To compare the polymer blend/MWNT nanocomposite with a pure polymer/MWNT nanocomposite, PLA/MWNT, PBAT/MWNT, and PLA/PBAT/MWNT nanocomposite systems were prepared. TEM and SEM were used to observe that one phase has better affinity with the MWNT, while the MWNT was found to increase both the thermal properties of the PLA/PBAT blends and rheological properties of the PLA/PBAT/MWNT nanocomposite with distinct shear‐thinning behavior due to the addition of the MWNT. An increase in the storage (G′) and loss (G″) moduli for the PLA/PBT/MWNT nanocomposite was also observed.