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1.
In this study, a series of manganese [Mn]-doped zinc oxide [ZnO] hierarchical microspheres [HMSs] are prepared by hydrothermal method only using zinc acetate and manganese acetate as precursors and ethylene glycol as solvent. X-ray diffraction indicates that all of the as-obtained samples including the highest Mn (7 mol%) in the crystal lattice of ZnO have a pure phase (hexagonal wurtzite structure). A broad Raman spectrum from as-synthesized doping samples ranges from 500 to 600 cm-1, revealing the successful doping of paramagnetic Mn2+ ions in the host ZnO. Optical absorption analysis of the samples exhibits a blueshift in the absorption band edge with increasing dopant concentration, and corresponding photoluminescence spectra show that Mn doping suppresses both near-band edge UV emission and defect-related blue emission. In particular, magnetic measurements confirm robust room-temperature ferromagnetic behavior with a high Curie temperature exceeding 400 K, signifying that the as-formed Mn-doped ZnO HMSs will have immense potential in spintronic devices and spin-based electronic technologies.  相似文献   

2.
A series of novel hafnium (Hf) doped ZnO nanophotocatalyst were synthesized using a simple sol–gel method with a doping content of up to 6 mol%. The structure, morphology and optical characteristics of the photocatalysts were characterized by XRD, SEM, TEM, FTIR, XPS, DRS and PL spectroscopy. The successful synthesis and chemical composition of pure and doped ZnO photocatalysts were confirmed by XRD and XPS. DRS confirmed that the spectral responses of the photocatalysts were shifted towards the visible light region and showed a reduction in band gap energy from 3.26 to 3.17 eV. Fluorescence emission spectra indicated that doped ZnO samples possess better charge separation capability than pure ZnO. The photocatalytic activity of Hf-doped ZnO was evaluated by the methylene blue (MB) degradation in aqueous solution under sunlight irradiation. Parameters such as irradiation time and doping content were found effective on the photoactivity of pure ZnO and Hf-doped ZnO. The photocatalysis experiments demonstrated that 2 mol% Hf-ZnO exhibited higher photocatalytic activity as compared to ZnO, ZnO commercial and other hafnium doped ZnO photocatalysts and also revealed that MB was effectively degraded by more than 85% within 120 min. The enhanced photoactivity might be attributed to effective charge separation and enhanced visible light absorption. It was concluded that the presence of hafnium within ZnO lattice could enhance the photocatalytic oxidation over pure ZnO.  相似文献   

3.
《Ceramics International》2023,49(4):5676-5686
Mixed metal oxides with chemical formula FexAl2-xO3 (where x = 0.2–1.0) (FANF) was synthesized via sol-gel auto combustion process. X-ray diffraction, field emission scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy were employed to characterize produced oxide materials. The final product FANF was sintered for 5 h at 1100 °C. The TG-DTA validated the mixed metal oxides phase evolution and steady-state temperature. The replacement of aluminium ions results in orthorhombohedral structure in mixed metal oxides (MMO). The bandgap decreased from 3.72 eV to 3.21 eV and the crystallite size decreased from 28 nm to 14 nm as the iron content increased in the sample FexAl2-xO3 (where x = 0.2–1.0). The FT-IR confirmed no impurity peaks and the single phase with iron oxide band is near 432 cm?1, while the aluminium oxide band is 565–600 cm?1. Microstructural investigation shows flake-like growth, and EDS confirmed a stoichiometric ratio of MMO. Iron-substituted aluminate gas sensors detected CO, H2S, and NO2 at temperature ranging from 25 to 300 °C. Fe0.6Al1.4O4 (F3ANF) sensor responded 46.69% towards 100 ppm H2S at 200 °C. Overall, the results showed that a flake-like FANF sensor can be used effectively as a H2S gas sensor.  相似文献   

4.
《Ceramics International》2023,49(5):7284-7288
A simple cost-effective co-precipitation method was adopted to prepare ZnO nanoparticles from a metal organic framework. The synthesized ZnO nanoparticles were blended with graphene oxide (GO) to prepare the ZnO-GO nanocomposite. The physicochemical properties of ZnO nanoparticles and ZnO-GO nanocomposite were analyzed via various techniques. The structural behavior of ZnO and ZnO-GO nanocomposite was studied by XRD and FT-IR analysis. The XRD profile confirms the hexagonal structure with an average crystallite size of 19.4 nm for ZnO and 16.2 nm for ZnO-GO nanocomposites. The functional groups and the vibration modes of the samples were examined through FT-IR. It confirms the metallic presence in the ZnO and ZnO-GO samples in the wavenumber range of 400–600 cm?1. The optical properties of ZnO and ZnO-GO were studied via UV–vis spectra. The surface morphology of the samples was recorded through FESEM, and the elemental presence in the samples was examined by EDX. It confirms that the prepared samples are spherical in shape with uniform size distributions. Cyclic voltammetry has been used to study the redox behavior of electroactive ZnO and ZnO-GO composites.  相似文献   

5.
《Ceramics International》2022,48(5):6103-6115
The synthesis of silver doped cobalt oxide nanoparticles by microwave-assisted method and their structural, optical, antibacterial activities are presented in this study. The doping concentrations were chosen as 5, 10, 15, and 20 wt percentages. The sample was undergone powder X-ray diffraction studies and the result shows the good crystalline nature of the sample. Also, the average crystallite size increases from 13.95 nm, 21.26 nm, 26.13 nm, and 28.35 nm with different doping concentrations. The transmission electron microscopy image shows cubic and spherical morphology. The optical properties were tested by UV–vis–NIR absorption spectrum. It indicates the decrease of band gap value. From the antibacterial activity studies, the 20 wt % Ag doped nanoparticles exhibit better activity.  相似文献   

6.
The main aim of this study is to investigate the effect of silver‐doped zinc oxide (Ag‐ZnO) loading on the structural, morphological, thermal and electrical properties, and gas sensing behavior of polypyrrole (PPy)/phenothiazine (PTZ)‐blend nanocomposites. The composites are characterized by FTIR, XRD, SEM, TEM, DSC, TGA, and impedance studies. FTIR spectra exhibit the presence of Ag‐ZnO in the PPy/PTZ blend. XRD analysis shows that the semicrystalline behavior of the polymer blend is greatly enhanced by the addition of Ag‐doped ZnO particles. Uniform dispersion of nanoparticles in the polymer is obtained from SEM analysis. The TEM images confirm the presence of spherically shaped nanoparticles in PPy/PTZ blend with a size of 10–25 nm. The DSC measurement indicates that the glass transition temperature of PPy/PTZ blend was significantly improved in the presence of Ag‐doped ZnO nanoparticles. The thermal decomposition temperature of nanocomposite obtained from TGA shows an increase with increase in the content of Ag‐ZnO particles. The incorporation of Ag‐doped ZnO nanoparticles to PPy/PTZ blend exhibit increase in the AC conductivity and dielectric properties of the nanocomposite, due to the pilling of charges at the extended interface of the composite system. The DC conductivity of the nanocomposite increases with the loading of nanoparticles. The ammonia gas sensing performance of PPy/PTZ/Ag‐ZnO nanocomposite is analyzed, and the result shows that the fabricated blend composite can be used as a promising candidate for the easy access of gas molecules. J. VINYL ADDIT. TECHNOL., 26:187–195, 2020. © 2019 The Authors. Journal of Vinyl and Additive Technology published by Wiley Periodicals, Inc. on behalf of Society of Plastics Engineers.  相似文献   

7.
Nanocomposites of polyaniline as a conducting polymer and main matrix, zinc oxide nanoparticles as inorganic filler and nylon 6,6 as supporting matrix were prepared by solution mixing process in a common solvent. DC electrical conductivity and its thermal stability at different temperatures under ambient atmospheric conditions were studied for the nanocomposites. The stability studies were carried out by two slightly different techniques, i.e., cyclic ageing and isothermal ageing. The results showed that the DC electrical conductivity of the nanocomposites decreased with increase in the content of zinc oxide nanoparticles whereas the thermal stability in terms of DC electrical conductivity retention was slightly improved in few cases but not for all samples. The advance analytical techniques such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis and X-ray diffraction (XRD) were also used to characterize the selected samples. It was also observed that zinc oxide nanoparticles in the nanocomposites were homogeneously distributed; however, some clusters/aggregates were also present. The FTIR results showed the existence of some interaction between the individual components of the nanocomposites as evident from the little shift in the peaks of FTIR spectra. This result was also supported by XRD data.  相似文献   

8.
In the present work, Zeolite 13X and carbon black nanoparticles (CBNPs) reinforced polyvinylidene fluoride (PVDF) nanocomposites were obtained by a simple solvent casting technique. The structural, morphological and thermal properties of PVDF/Zeolite 13X/CBNPs nanocomposites with various loadings of Zeolite 13X and CBNPs were investigated using Fourier-transform infrared spectroscopy, X-ray diffraction, Scanning electron microscopy and thermo-gravimetric analysis. The dielectric studies were carried out in the 50 Hz–10 MHz frequency range at room temperature. The electromagnetic interference (EMI) shielding effectiveness (SE) of PVDF/Zeolite 13X/CBNPs nanocomposite was investigated in the 8–18 GHz frequency region (X-band and Ku-band). The maximum EMI SE of approximately −11.1 dB (8–12 GHz) and −11.5 dB (12–18 GHz) was observed for PVDF/CBNPs nanocomposites with 10 wt% loading of CBNPs. These findings emphasize the application of PVDF/Zeolite 13X/CBNPs nanocomposites as a potential EMI shielding material.  相似文献   

9.
《Ceramics International》2020,46(3):2969-2978
Tin doped nanomagnetites, SnxFe3-xO4, were synthesized with various concentrations of Sn2+ ion (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) by co-precipitation method. XRD, VSM, TG-DTA, SEM-EDX and UV–Vis were used to characterize and study the structural, magnetic, thermal, and optical properties of SnxFe3-xO4 nanoparticles. XRD confirmed the presence of cubic structure and spinel phase of tin doped magnetites. The d-spacing, lattice parameter, density, crystallite size and cation distribution were derived from the XRD analysis. The M − H curves exhibited changes in saturation magnetization (Ms), coercive field (Hc), remanent magnetization (Mr) and susceptibility (χ), with increasing concentration of non-magnetic Sn2+ ions. Differential thermal analysis was used to study the thermal stability of SnxFe3-xO4 nanoparticles. The SEM images revealed the surface morphology of the nanoparticles and the EDX spectra showed an increase in the Sn content and a corresponding decrease in the Fe content for the tin doped samples. The optical bandgap was found to be centered at 3.9 eV for the synthesized materials. This systematic study may be the first comprehensive report on synthesis and characterization of tin doped magnetites.  相似文献   

10.
《Ceramics International》2023,49(2):2282-2295
In the present work, we studied the role of Fe and Pr addition on the structural, optical and antibacterial properties of spherical ZnO nanoparticles synthesized via sol gel method. The lattice constants values increased, while the average crystallite size decreases as the Pr concentration varies from 0.00 to 0.04. The Fe and Pr cations insertion in the Wurtzite structure were also confirmed by the changes in Zn–O bond length (1.9763 Å to 1.9793 Å for 0.00 ≤ y ≤ 0.04). Raman and FTIR spectroscopies validated the ZnO single-phase formation, and the analysis suggests the existence of oxygen vacancies. The samples showed agglomerated spherical morphology and formation of nanoplate homogeneously organized, while the textural properties were affected by the Fe inclusion. All samples presented band gap values lower than expected for bulk ZnO and the lowest values were obtained for samples containing Fe and Pr. The analysis and deconvolution of photoluminescence spectra confirmed the structural defects formation, caused by the synthesis conditions used and dopants ions inclusion. The antimicrobial activity against Escherichia coli and Staphylococcus aureus using the direct contact method showed superior activity for S. aureus due to the nanoparticles-bacteria interactions. The synergistic effect of dopants may have contributed to the better performance observed against S. aureus, while the Pr concentration directly influenced the inhibitory effect of E. coli. Therefore, the synthesized materials are promising to eliminate pathogenic microorganisms.  相似文献   

11.
Nanocomposites of LDPE/LLDPE/nanoclay have been prepared using a lab‐scale co‐rotating twin screw extruder. Using XRD, tensile testing, AFM, TGA, effects of some material properties and one processing parameter on mechanical and thermal properties of the prepared nanocomposites were evaluated. Tensile properties indicated that all the prepared nanocomposites exhibited a significant improvement in elastic modulus and toughness compared to pristine LDPE/LLDPE blends of the same composition. Thermal stability of nanocomposites in the air and nitrogen atmosphere was improved. XRD patterns and AFM micrographs showed semi‐exfoliated and intercalated microstructures for the prepared nanocomposites with different orders of mixing.  相似文献   

12.
In this work, we have prepared Co‐doped ZnO nanocomposites by zinc nitrate and cobalt sulfate as new precursors via the coprecipitation method and the samples were followed to identify the morphological, optical, structural, and magnetic properties. The XRD patterns revealed the crystalline nature of nanoparticles with hexagonal wurtzite structures, which meant that Co impurity did not disturb the structure of pure ZnO and the minimum crystallite size of nanoparticles was calculated to be around 37 nm. The XRD patterns also showed the lattice parameter increase owing to the incorporation of a Co dopant. The TEM results revealed the sphere‐like particles whose size varied between 56 and 88 nm in diameter at a 4% level of impurity. DRS analysis identified that the band gap energy decreased from 3.18 eV for the pure substance to 2.36 eV for the 10% impure substance. VSM analysis exhibited that the saturation magnetization value increased to 8.4 × 10?3 emu/g for the highest Co content of 10%, which indicated the ferromagnetic behavior of NPs.  相似文献   

13.
《Ceramics International》2021,47(18):25580-25592
Herein, titanium dioxide (TiO2) nanoparticles doped with various concentrations (0–7 wt %) of niobium (Nb) are hydrothermally synthesized and used effectively as a photoelectrode for application in dye-sensitized solar cells (DSSCs). The rutile-to-anatase phase transition, accompanied by a change in crystallite size from 23.75 to 9.77 nm, is confirmed via X-ray diffraction (XRD) and Fourier transform (FT)-Raman spectroscopy. In addition, the prepared Nb–TiO2 nanoparticles exhibit a spherical morphology with a mean grain diameter of 43.38–50.69 nm. Further, X-ray photoelectron spectroscopy (XPS) indicates a shift in the Fermi level of the TiO2 towards the conduction band minimum, and an increase in the bandgap from 2.69 to 2.88 eV, with increasing Nb concentration. The resulting increases in the short-circuit current density (JSC) and open circuit voltage (VOC) with the increased injection and conductivity of electrons lead to the enhancement of the DSSC performance. EIS measurements represents the effect of Nb doping on charge transporting and recombination behavior of DSSCs. Moreover, the Nb–TiO2-based DSSCs provide a better power conversion performance as compared to that of the pristine TiO2.  相似文献   

14.
Synthesis of DBSA-doped PPy–WO3 (organic–inorganic) nanocomposites, using a novel approach, has been proposed, and further envisaged for their structural, compositional, morphological, optical and electrical properties. DBSA-doped PPy–WO3 nanocomposites demonstrate superior above mentioned properties than their counterparts i.e. either PPy or WO3. The XRD spectra of nanocomposites supported to conclude that both i.e. PPy and DBSA have no impact on the crystallinity of WO3 nanoparticles. The chemical structure of DBSA-doped PPy–WO3 nanocomposites have been elucidated using FTIR spectra. The morphologies and surface roughnesses of the DBSA-doped PPy–WO3 nanocomposites were confirmed using scanning electron microscope and atomic force microscope images, respectively. Interconnected type morphology and 13 nm average surface roughness were confirmed for DBSA doped PPy–WO3 hybrid nanocomposites. The EDX and XPS analyses evidence that, the formation of DBSA doped PPy–WO3 hybrid nanocomposites without any elemental impurities. The absorption peak of DBSA-doped PPy–WO3 nanocomposites shift towards the lower wavelength side as compared to the PPy–WO3 (50%) hybrid nanocomposites. Anionically charged sulfonate group which is supposed to stabilize doped state of the DBSA-PPy–WO3 nanocomposites, may be responsible for this shift. The dc electrical conductivity of DBSA-doped PPy–WO3 nanocomposites increases as the content of DBSA is increased from 10 to 50% this could be accounted for by the generation of conduction path through the PPy–WO3 nanocomposites as DBSA has anionic surfactant nature by preventing an agglomeration of functional material.  相似文献   

15.
《Ceramics International》2022,48(13):18324-18329
The use of plant extracts in the synthesis of nanoparticles has several advantages over traditional chemical-based synthesis methods. The synthesis of ZnO, Polyethylene Glycol ZnO (PEG), and Chitosen (Chit) ZnO nanoparticles using moringa oleifera leaf extracts as an effective reducing agent is described in this report. The colour of the reaction mixture changes from yellowish brown to white as nano metal oxide forms. Surface modifying agents for ZnO nano oxide included polyethylene glycol and chitosan. UV–Vis and FTIR spectroscopy were used to investigate the optical characteristics of produced nano oxides. The structural, elemental analysis, and morphology of nano oxides were studied using XRD, FESEM, EDAX, and HRTEM techniques. XRD validated the hexagonal wurtzite structure, and the average crystallite size of the ZnO, PEG-ZnO, and Chit-ZnO nanoparticles were 35 nm, 32 nm, and 28 nm, respectively. The band gaps of ZnO, PEG-ZnO, and Chit-ZnO nanoparticles were found to be 3.12 eV, 3.18 eV, and 3.14 eV, respectively, using UV–Visible analysis. ZnO, PEG-ZnO, and Chit-ZnO nanoparticles were found to be generally spherical and nano in size, according to SEM and TEM examination. According to the findings, moringa oleifera leaf extract-assisted ZnO-based nanoparticles are promising materials for various applications.  相似文献   

16.
《Ceramics International》2022,48(14):20418-20425
Magneto-optical TiO2/xCoFe2O4 nanocomposites having various concentrations of CoFe2O4 (x = 2, 4 and 6 wt %) were prepared using facile mechanical mixing. X-ray diffraction was employed for the phase examination and microstructure parameters. X-ray diffraction spectra proved the formation of two separate phases: tetragonal titanium dioxide (TiO2) and face-centered cubic cobalt iron oxide. The structure was further verified by recognizing the selected area electron diffraction (SAED) pattern recorded by a high-resolution transmission microscope. The optical investigation of the prepared nanocomposites verified that the optical band gap values varied from 3.1 eV for pure TiO2 to 3.05 eV for TiO2/CoFe2O4 (6 wt %). The refractive index, optical dielectric constant and loss factor were discussed in detail. The nanocomposites (TiO2/xCoFe2O4) demonstrated ferromagnetic characteristics and their magnetic parameters were affected by the CoFe2O4 percentage in the composites. The sample x = 2 wt % depicted the maximum magnetic exchange bias at room temperature. Moreover, it showed maximum coercivity (HC) and magnetic squareness ratio (SQ), which makes it suitable for spintronic applications.  相似文献   

17.
武利顺 《精细化工》2013,30(5):566-569,590
以邻苯二甲酸二丁酯(DBP)和N,N-二甲基乙酰胺(DMAc)为混合稀释剂,采用热致相分离法(TIPS)制备了聚偏氟乙烯(PVDF)/酚酞型聚醚砜(PES-C)共混膜,考察了不同凝固浴温度对膜结构和性能的影响。采用扫描电镜观察了膜的结构,测试了膜的纯水通量。运用DSC和XRD方法检测了膜的结晶性能。将制备的膜在膜生物反应器(MBR)中运行测试了膜的污水通量和出水指标。随凝固浴温度的升高,共混膜的最高熔融温度上升,膜中α晶型的含量增加。在凝固浴温度为25℃时,膜形成了较为致密的皮层结构和较为疏松的支撑层结构,此时共混膜的纯水通量和污水通量达到最大值,且MBR出水COD和NH4+-N含量达到排放要求。  相似文献   

18.
Regarding advanced 5G mobile communication, microwave dielectric ceramics are considered as the most potential materials to develop new-generation base station resonators. Herein, ZnNb2O6 ceramics with εr of approximately 24 have been prepared using the solid-state reaction method, with tailored extra ZnO of x mol% (x = 1, 2 and 3). We have for the first time applied the P-V-L chemical bond theory to investigate ZnNb2O6 ceramics with ZnO doping, by exploring the relationship of dielectric properties and chemical bond characteristics. Particularly, the Raman spectra demonstrates that the full width at half maximum of υ1 (Ag) vibration mode can exhibit significant correlation with the quality factor (Q × f ). To further support the experimental study, we have also conducted the first-principle calculation of electron density difference via CASTEP package, which further confirms the change of temperature coefficient of resonance frequency (τf ). Our newly designed ZnNb2O6 ceramics doped with 1 mol% ZnO exhibit excellent dielectric properties, i.e., εr = 23.74, Q × f = 102,824 GHz and τf = ?55.38 ppm/°C, which demonstrates great potential to construct miniaturized 5G base station with advanced ceramic dielectrics.  相似文献   

19.
Zn1−xCoxO (x==0.05, 0.10, 0.15) nanoparticles have been synthesized by an alternative wet-chemical synthesis route using the SimAdd technique. The as-obtained powders were investigated by FT-IR spectroscopy, X-ray diffraction and thermal analysis correlated with evolved gas analysis (TG–DTA–FT-IR) in order to determine their chemical nature, crystalline structure and to establish the decomposition sequences. The precipitates are generally amorphous, but low-intensity reflection peaks assigned both to the zinc oxalate dihydrate, and zinc hydroxide can be observed in the recorded patterns, indicating that hydroxy-oxalate precipitates were obtained. The structure, morphology and magnetic properties of the thermally treated samples have been investigated by X-ray diffraction, FT-IR, HRTEM, SAED, UV–vis and EPR. XRD studies reveal a hexagonal wurtzite-type structure for all Zn1−xCoxO samples. TEM investigations show particle size between 28 and 37 nm, with spherical and polyhedral shapes and with tendency to form aggregates. The presence of a Co3O4 secondary phase was evidenced by XRD, UV–vis and EPR for the Zn0.85Co0.15O sample. The ferromagnetic behavior of the samples was revealed. The paper highlights that by varying the cobalt concentration it is possible to modulate the structural, morphological, optical and magnetic properties.  相似文献   

20.
This study reports on the deposition of highly transparent, n-type ZnO thin films on glass substrate at 450?°C using spray pyrolysis processing, with the simultaneous insertion of yttrium (Y) at different percentages (0, 2, 5, 7?at%) as a dopant. The effect of Y doping on the structure, morphology and optical properties of Y doped ZnO (ZnO:Y) was investigated for optoelectronic applications. The obtained thin films were characterized by means of X-ray diffraction, field-emission scanning electron microscopy (FESEM), UV–visible absorbance measurements, photoluminescence (PL) and cathodoluminescence (CL) spectroscopy. The as-prepared films exhibit well-defined hexagonal wurtzite structure grown along [002]. Field emission scanning electron microscope micrographs of the pure ZnO and ZnO:Y showed that the films acquired a dominance of hexagonal-like grains, the morphology was influenced by Y incorporation. All the films showed high transparency in the visible domain with an average transmittance of 83%. The band gap energy, Eg, increased from 3.12?eV to 3.18?eV by increasing the Y doping concentration up to 5?at% and then decreased to 3.15?eV for 7?at% Y content. The PL and CL measurements reveal a strong ultraviolet (UV) emission, suggesting that the as-prepared ZnO:Y thin films can potentially be used in optoelectronic devices.  相似文献   

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