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1.
Synthesis of pure Zinc oxide (ZnO), Copper oxide (CuO) nanoparticles (NPs) and their (ZnO/CuO) nanocomposites (NCs) in 1:1 M ratio were successfully prepared by co-precipitation method. The structural properties of the as synthesized nanoparticles and nanocomposite materials were investigated using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) techniques. Optical band-gap studies were done using UV–Visible absorption spectroscopy. Photovoltaic properties of pure ZnO NPs, CuO NPs and ZnO/CuO NCs coated over a single-crystalline silicon solar cell were carried out to compare improvement of light-conversion efficiency in coated solar cell. The maximum light conversion efficiencies were found to be of 8.02% for CuO (3 mg/ml concentration) and 7.28% for ZnO NPs (3 mg/ml concentration), whereas that of mixed metal nanocomposite CuO/ZnO NCs was found to be 7.62%. at very low concentration of 1 mg/ml. This indicates with low concentration of mixed metal NCs an improvement in light efficiency can be obtained. The enhancement in efficiency could be due to formation of p - n heterojunction by CuO/ZnO NCs composites which enhances the number of electrons and holes participating in conduction on the surface.  相似文献   

2.
Polyaniline (PANI)/zinc oxide (ZnO) nanocomposite was synthesized by in-situ polymerization. X-ray diffraction patterns, UV?Cvisible spectroscopy, SEM, and TEM were used to characterize the composition and structure of the nanocomposite. Nanostructured PANI/ZnO composite was used as photocatalyst in the photodegradation of methylene blue dye molecules in aqueous solution. The photocatalytic activity of PANI/ZnO nanocomposite under UV and visible light irradiation was evaluated and was compared with that of ZnO nanoparticles. ZnO/PANI core?Cshell nanocomposite had greater photocatalytic activity than ZnO nanoparticles and pristine PANI under visible light irradiation. According to these results, application of PANI as a shell on the surface of ZnO nanoparticles causes the enhanced photocatalytic activity of the PANI/ZnO nanocomposite. Also UV?Cvisible spectroscopy studies showed that the absorption peak for PANI/ZnO nanocomposite has a red shift toward visible wavelengths compared with the ZnO nanoparticles and pristine PANI. The effect of different operating conditions on the photocatalytic performance of PANI/ZnO nanocomposite in the photodegradation of methylene blue dye molecules was investigated in a bath experimental setup.  相似文献   

3.
常青  管静  孟天明 《无机化学学报》2021,37(9):1683-1690
应用SiO2纳米粒子、CdTe量子点和Au纳米粒子,采用逐层吸附法制备SiO2@CdTe@Au纳米复合材料。同时对样品进行了测试和表征,从多个方面证明纳米复合材料成功制备。利用Z扫描技术测量了SiO2@CdTe和SiO2@CdTe@Au纳米复合材料在纳秒激光脉冲作用下的非线性吸收光学特性。实验结果表明:SiO2@CdTe和SiO2@CdTe@Au纳米复合材料均表现出饱和吸收特性。SiO2@CdTe@Au较SiO2@CdTe纳米复合材料具有更强的非线性光学特性,并对其机理进行了分析。  相似文献   

4.

New polypyrrole (PPy)-derived polymer/ZrO2 nanocomposite materials are prepared by single-step oxidative polymerization of pyrrole (Py) and/or N-methylpyrrole (mPy) in the presence of HCl-functionalized ZrO2 nanoparticles and ammonium persulfate. The physicochemical features of the PPy–ZrO2, poly(Py-co-mPy)–ZrO2 and PmPy–ZrO2 hybrids were analyzed by XPS, FTIR, XRD and UV–Vis techniques. To explore the advantages of these nanocomposites for potential applications, their thermal, conductive and electrochemical properties were investigated. The characterization reveals that a chemical bonding, based on electrostatic interactions, is established between the polymers and the ZrO2 nanoparticles. Interestingly, it is found that the growth of polymer on the surface of Cl-functionalized ZrO2 becomes more significant as the Py moiety (–NH– species) content in the polymer increases. The thermal stability and conductivity of the polymers increase by hybridization with the ZrO2 nanoparticles. This is assigned to the affective interaction of the polymers with the ZrO2 nanoparticles. Particularly, the resulting nanocomposites keep high conductivities, ranging between 0.323 and 0.929 S cm−1. Finally, voltammetric characterization shows that the PPy–ZrO2 and poly(Py-co-mPy)–ZrO2 nanocomposites are electroactive, thus demonstrating their capability for electrochemical applications. These results highlight the great influence of the nanoparticle interface and the nature of monomer on the nanocomposite formation and properties.

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5.
In this study, the synthesis of ZnO/SiO2 nanocomposites using bamboo leaf ash (BLA) and tested their photocatalytic activity for rhodamine B decolorization have been conducted. The nanocomposites were prepared by the sol–gel reaction of zinc acetate dihydrate, which was used as a zinc oxide precursor, with silica gel obtained from the caustic extraction of BLA. The effect of the Zn content (5, 10, and 20 wt%) on the physicochemical characteristics and photocatalytic activity of the nanocomposites was investigated. The results of X-ray diffraction, scanning electron microscopy, gas sorption, and transmission electron microscopy characterization confirmed the mesoporous structure of the composites containing nanoflower-like ZnO (wurtzite) nanoparticles of 10–30 nm in size dispersed on the silica support. Further, the nanocomposites were confirmed to be composed of ZnO/SiO2 by X-ray photoelectron spectroscopy analysis. Meanwhile, diffuse-reflectance UV–visible spectrophotometry analysis of the nanocomposites revealed band gap energies of 3.38–3.39 eV. Of the tested nanocomposites, that containing 10 wt% Zn exhibited the highest decolorization efficiency (99%) and fastest decolorization rate. In addition, the degradation efficiencies were not reduced significantly after five repeated runs, demonstrating the reusability of the nanocomposite catalysts. Therefore, the ZnO/SiO2 nanocomposite obtained from BLA is a promising reusable photocatalyst for the degradation of dye-polluted water.  相似文献   

6.
Novel ternary ZnO/Ag3VO4/Ag2CrO4 nanocomposites were successfully fabricated via preparation of ZnO/Ag3VO4 followed by coupling of it with Ag2CrO4 through facile ultrasonic-assisted method. The resultant samples were carefully characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive analysis of X-rays, UV–vis diffuse reflectance spectroscopy, Fourier transform-infrared spectroscopy, and photoluminescence techniques. Photocatalytic activity for degradation of organic dyes, including rhodamine B, methylene blue, and methyl orange was examined under visible-light irradiation. Among the prepared samples, the ternary nanocomposite with 20% of Ag2CrO4 demonstrated the superior activity. This nanocomposite showed 10.6, 2.9, and 3.0-folds greater activity compared to ZnO, ZnO/Ag2CrO4, and ZnO/Ag3VO4, respectively. The enhanced activity was attributed to more harvesting of the visible-light irradiation and efficiently separation of the photogenerated charge carriers in the ternary nanocomposites. To understand efficiently separation of the charge carriers, a plausible diagram was proposed based on formation of tandem n-n heterojunctions.  相似文献   

7.
In this study, the photocatalytic degradation of Reactive Blue 81 (RB81) using synthesized NiO-doped ZnO–ZrO2 nanoparticles under UV irradiation was investigated. Then, the products were characterized by Scanning electron microscope (SEM), X-ray diffraction (XRD), and diffuse reflectance spectroscopy (DRS). The removal rate of RB81 using ZnO–ZrO2 after 180?min of irradiation was 96.7%. Nickel oxide (NiO) was used as an additive to ZnO–ZrO2 for improvement of RB81 degradation via photocatalysis process. Photodegradation of RB81 was achieved to 100% using ZnO–ZrO2–NiO nanoparticles with ratio of 1:2:0.3 after 180?min of irradiation. There was a red shift in absorption bands (from 410?nm to 435?nm) observed in increasing of NiO to ZnO–ZrO2 nanoparticle, that it might lead to a higher photocatalytic activity under visible light. Response surface methodology (RSM) was used for optimization of experimental and these results were obtained: solution pH = 3, ZnO–ZrO2–NiO dosage = 15?mg/L, and the initial RB81 concentration = 5?mg/L. The photodegredation of RB81 followed pseudo-first order kinetic according to the Langmuir–Hinshelwood model.  相似文献   

8.
The thermal, morphological and optical studies of BaSO4 and MMT (nanoclay) embedded in PVDF were investigated. Nanocomposites samples of PVDF–BaSO4–MMT were prepared by varying the loadings (1–4 mass%) in case of BaSO4 and MMT nanomaterials, respectively. Polyvinylidene fluoride–barium sulfate-montmorillonite (PVDF–BaSO4–MMT) nanocomposites were prepared by solvent-mixing technique. Nanoparticles were synthesized by in situ deposition technique with the help of nonionic polymeric surfactant, and the particle size of nanoparticles was recognized by scanning electron microscopy (SEM) analysis which confirms that the particle has diameter of 80–90 nm. As prepared, nanocomposites films (thickness, 25 μm) were characterized by Fourier transform infrared microscopy (FTIR), SEM and electron diffraction spectroscopy (EDS). FTIR shows that all the chemical constituents were present in the nanocomposites, whereas SEM analysis suggested that the nanofillers dispersed well in polymer matrix and EDS showed the elemental composition of nanocomposite samples. Thermal properties of nanocomposites were studied by using TG/DTA/DTG. TG/DTA studies showed decomposition temperature of pure PVDF is 473.5 °C. The decomposition temperature (T d) of nanocomposites was increased by 93 °C in case of nanocomposites with addition of both BaSO4 and MMT nanomaterials. The difference in the thermal degradation temperature was found to be 1.2% higher in case of addition of BaSO4 nanoparticle as compared to nanoclay. The obtained transparent nanocomposite films were characterized by using UV–Vis spectrophotometer which shows that transparencies of nanocomposites are maintained in visible region, the intensity of absorption band in UV region is increased with the addition of BaSO4 nanoparticles, while in case of addition of nanoclay the UV region does not show drastic changes. Addition of both nanoparticle and nanoclay shows higher absorption in comparison with the individual samples. But further, doubling the amount of nanoparticle and nanoclay shows decrease in UV absorption. Overall, the results of thermal studies show that the incorporation of BaSO4 and MMT could significantly improve the thermal properties of nanocomposites.  相似文献   

9.
The effect of the dispersion of zinc oxide (ZnO) nanoparticles in the zinc ion conducting gel polymer electrolyte is studied. Changes in the morphology/structure of the gel polymer electrolyte with the introduction of ZnO particles are distinctly observed using X-ray diffraction and scanning electron microscopy. The nanocomposites offer ionic conductivity values of >10?3 S cm?1 with good thermal and electrochemical stabilities. The variation of ionic conductivity with temperature follows the Vogel–Tamman–Fulcher behavior. AC impedance spectroscopy, cyclic voltammetry, and transport number measurements have confirmed Zn2+ ion conduction in the gel nanocomposites. An electrochemical stability window from ?2.25 to 2.25 V was obtained from voltammetric studies of nanocomposite films. The cationic (i.e., Zn2+ ion) transport number (t +) has been found to be significantly enhanced up to a maximum of 0.55 for the dispersion of 10 wt.% ZnO nanoparticles, indicating substantial enhancement in Zn2+ ion conductivity. The gel polymer electrolyte nanocomposite films with enhanced Zn2+ ion conductivity are useful as separators and electrolytes in Zn rechargeable batteries and other electrochemical applications.  相似文献   

10.
The toxic dye pigments, even in small quantities, can damage ecosystems. Removing organic, inorganic, and microbiological contaminants from wastewater via heterogeneous photocatalysis is a promising method. Herein, we report the band structure tuning of ZnO/CuO nanocomposites to enhance photocatalytic activity. The nanocomposites were synthesized by a chemical approach using step-wise implantation of p-type semiconductor CuO to n-type semiconductor ZnO. Various characterization techniques such as X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX) and UV spectroscopy were used to investigate the crystal structure, surface morphology, elemental composition and optical properties of the synthesized samples. As the CuO content increased from 10% to 50% in ZnO/CuO nanocomposites, the optical bandgap decreased from 3.36 to 2.14 eV. The photocatalytic activity of the samples was evaluated against the degradation of methylene blue (MB) under visible irradiation. Our study demonstrates a novel p–n junction oxide photocatalyst based on wt. 10% CuO/ZnO with superior photocatalytic activity. Effectively 66.6% increase in degradation rate was achieved for wt. 10% CuO/ZnO nanocomposite compared to pure ZnO nanoparticles.  相似文献   

11.
Pulsed laser ablation in liquid (PLAL) has verified its surpassing advantages in the fabrication of several high purity nanostructured metals and metal oxides. In this work, ZnO/CuO heterostructure nanocomposites have been fabricated by laser ablation a Q switched Nd: YAG laser beam (1064 nm, 10 Hz, pulse energy and pulse with 30 mJ and 10 ns) is focused on the surface of the ZnO thin film for 10 min. The fabricated ZnO/CuO nanocomposite was then characterized using transmission electron microscopy (TEM), UV–vis spectrophotometer, X-ray diffraction (XRD), and Raman spectroscopy to investigate the structural, compositional, and optical properties of the fabricated nanocomposite. The synthesized nanocomposites were evaluated as antibacterial agents against both the gram-positive bacterium S. aureus subsp. aureus ATCCBAA-977, and the gram-negative bacteria E. coli ATCC8739, K. pneumoniae subsp. pneumoniae ATCC700603, and P. aeruginosa ATCC27853. The as-fabricated ZnO/CuO nanocomposite demonstrated outstanding antibacterial activity except in the case of K. pneumoniae subsp. pneumoniae ATCC700603 while the maximum activity was observed against E. coli ATCC8739.  相似文献   

12.
The p-n junction ZnO/CuO nanocomposite photocatalysts are prepared via the copreripitation route. The detailed structural, compositional and optical characterization and physico-chemical properties of the obtained products are analyzed by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), photoluminscience spectra (PL) and electron spin resonance (ESR) spin-trapping techniques. The experimental results showed that the absorption wavelength range of the ZnO/CuO nanocomposite was notably extended towards the visible-light region (400–500 nm). The photocataltic activity of the ZnO/CuO nanocomposite was evaluated based on the decomposition of by methyl orange (MeO) in aqueous solution under UV-vis light irradiation. The photocatalytic activity of ZnO/CuO nanocomposite is found much better than of bare ZnO photocatalyst under the identical conditions. Factors influencing photocatalytic activity and the mechanism of photocatalysis reaction were also addressed.  相似文献   

13.
In the present work, we have fabricated a novel mesoporous TiO2–rGO nanocomposite by a facile one-step solvothermal method using titanic sulfate as the TiO2 source. The as-prepared composites were characterized by transmission electron microscopy, X-ray diffraction; UV–Vis diffuse reflectance spectra, X-ray photoelectron spectroscopy and photoluminence spectra. In situ nucleation and anchoring of TiO2 nanoparticles onto a graphene sheet is favorable fpr forming an intimate interfacial contact, and the chemically bonded TiO2–rGO nanocomposites commendably enhanced their photocatalytic activity in the photodegradation of rhodamine B and phenol. The high photocatalytic activity of the as-synthesized nanocomposites are primarily ascribed to the mesoporous structure, efficient charge transportation and separation with enhanced visible light absorption, which come from the appealing nanoarchitecture, for instance, ultra-dispersed and ultra-small TiO2 nanocrystals along with intimate and absolute interfacial contact between the TiO2 nanocrystals and the graphene sheet.  相似文献   

14.
Metal oxide frame works along with carbon materials have been attracting tremendous attention of researches as the potential materials for energy and environmental remediation. In the present work heterostructures of (ZnO/CuO)/rGO ternary nanocomposites were synthesized by solid-state method. The crystalline structure of the nanoparticles was obtained from the XRD analysis. Optical band gap of the ZnO nanoparticles (3.1 eV) is tuned to 2.8 eV in the synthesized (ZnO/CuO)/rGO ternary nanocomposites. Field emission scanning electron microscope images of the (ZnO/CuO)/rGO ternary nanocomposites revealed formation of well-developed flowers like morphology of (ZnO/CuO) nanoparticles on rGO sheets. Photoluminescence spectroscopy analysis of (ZnO/CuO)/rGO ternary nanocomposites show enhancement in the electron-hole pair separation and thereby diminishing electron-hole pairs recombination rates effectively. In the present work, the photocatalytic activity of the ZC3G15 ternary nanocomposites show 99% and 93% of degradation efficiency respectively against RhB dye and 4-chlorophenol for 20 min under visible light irradiation. Thus, the simple solid-state method provides the effective ternary nanocomposites heterostructures light harvesting material for energy and environmental remediation.  相似文献   

15.
The polyaniline/zinc oxide (PANI/ZnO) nanocomposites were prepared by in situ polymerization of aniline monomer with ZnO nanomaterials and applied as a photocatalyst for the degradation of methylene blue (MB) dye. The morphological observations elicited the agglomerations of PANI sheets which occurred due to the interaction between PANI and ZnO nanomaterials in PANI/ZnO nanocomposites. As compared to pristine PANI, the UV–vis spectra exhibited that the absorption peak of ππ* transitions considerably shifted to higher wavelength at 360 nm from 325 nm in the nanocomposites. The photocatalytic activity results indicated the substantial degradation of MB dye by ~76% over the surface of PANI/ZnO nanocomposite catalyst under light illumination. The PANI/ZnO nanocomposites showed three times higher photocatalytic activity to MB dye degradation compared to pristine PANI might due to high photogenerated electron (ē)–hole (h+) pairs charge separation.  相似文献   

16.
Zirconia/polydopamine (ZrO2/PDA) nanocomposite multilayer films were constructed on Si substrate via a novel nonelectrostatic layer‐by‐layer (NELBL) assembly technique. The building block of this technique is the newly reported dopamine molecule, which can be attached to almost all material surfaces and undergo oxidation‐polymerization to form PDA layers; more importantly, the outer hydroxyl groups of the PDA layer can chelated with certain inorganic oxide nanoparticles to generate oxide films. Thus, ZrO2/PDA nanocomposite multilayer films were fabricated by sequential NELBL deposition of PDA and ZrO2 nanoparticles. The formation of the ZrO2/PDA nanocomposite multilayer films was monitored by the water contact angle (WCA) and ellipsometric thickness measurements, while the microstructure of the fabricated films was analyzed by means of atomic force microscope (AFM), field emission scanning electron microscope (FESEM), X‐ray photoelectron spectrum (XPS), and X‐ray diffraction (XRD) analysis. The mechanical and anticorrosion behaviors of the annealed ZrO2/PDA nanocomposite multilayers were found to be greatly enhanced as compared with that of the annealed homogeneous ZrO2 film. The better mechanical and anticorrosion behaviors of the annealed ZrO2/PDA nanocomposite multilayers than the annealed homogeneous ZrO2 film may be closely related to their special microstructure. Namely, the organic–inorganic hybrid microstructure of the annealed ZrO2/PDA nanocomposite multilayers may largely account for the increased nanohardness and corrosion resistance. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

17.
Due to the added value conferred by zinc oxide (ZnO) nanofiller, e.g., UV protection, antibacterial action, gas-barrier properties, poly(lactic acid) (PLA)–ZnO nanocomposites show increased interest for utilization as films, textile fibers, and injection molding items. The study highlights the beneficial effects of premixing ZnO in PLA under given conditions and its use as masterbatch (MB), a very promising alternative manufacturing technique. This approach allows reducing the residence time at high processing temperature of the thermo-sensitive PLA matrix in contact of ZnO nanoparticles known for their aptitude to promote degradation effects onto the polyester chains. Various PLA–ZnO MBs containing high contents of silane-treated ZnO nanoparticles (up to 40 wt.% nanofiller specifically treated with triethoxycaprylylsilane) were produced by melt-compounding using twin-screw extruders. Subsequently, the selected MBs were melt blended with pristine PLA to produce nanocomposite films containing 1–3 wt.% ZnO. By comparison to the more traditional multi-step process, the MB approach allowed the production of nanocomposites (films) having improved processing and enhanced properties: PLA chains displaying higher molecular weights, improved thermal stability, fine nanofiller distribution, and thermo-mechanical characteristic features, while the UV protection was confirmed by UV-vis spectroscopy measurements. The MB alternative is viewed as a promising flexible technique able to open new perspectives to produce more competitive multifunctional PLA–ZnO nanocomposites.  相似文献   

18.

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.

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19.
Nanocomposites of magnesium aluminium layered double hydroxides with carbonate anions (Mg–Al–CO3-LDHs) and ZnO nanorods were prepared by a homogeneous precipitation process. The ZnO nanorods give the calcined Mg–Al–CO3-LDHs, strong adsorbents of anionic dyes, photocatalytic activity. The nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, and UV–vis diffuse reflectance spectroscopy. The photocatalytic activity of the nanocomposites was investigated by degradation of acid red G in aqueous solution, and the nanocomposite with the ZnO-to-Mg–Al–CO3-LDHs mass ratio of 1:1 had the highest photocatalytic activity in this photocatalytic reaction.  相似文献   

20.
Polyaniline(PANI)/Tin oxide (SnO2) hybrid nanocomposite with a diameter 20–30 nm was prepared by co-precipitation process of SnO2 through in situ chemical polymerization of aniline using ammonium persulphate as an oxidizing agent. The resulting nanocomposite material was characterized by different techniques, such as X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Fourier Transform Infrared spectroscopy (FT-IR) and Ultraviolet–Visible spectroscopy (UV–Vis), which offered the information about the chemical structure of polymer, whereas electron microscopy images provided information regarding the morphology of the nanocomposite materials and the distribution of the metal particles in the nanocomposite material. SEM observation showed that the prepared SnO2 nanoparticles were uniformly dispersed and highly stabilized throughout the macromolecular chain that formed a uniform metal-polymer nanocomposite material. UV–Vis absorption spectra of PANI/SnO2 nanocomposites were studied to explore the optical behavior after doping of nanoparticles into PANI matrix. The incorporation of SnO2 nanoparticles gives rise to the red shift of π–π1 transition of polyaniline. Thermal stability of PANI and PANI/SnO2 nanocomposite was investigated by thermogravimetric analysis (TGA). PANI/SnO2 nanocomposite observed maximum conductivity (6.4 × 10?3 scm?1) was found 9 wt% loading of PANI in SnO2.  相似文献   

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