Journal of nanoscience and nanotechnology最新文献

The present work is focused on the fabrication of manganese dioxide/carbon dots (MnO₂/CDs) nanocomposites at room temperature in situ co-participation method in an aqueous medium and characterized. Our study showed that the concentration of CDs controls the morphology of MnO₂/CDs nanocomposite and also acted as a reducing agent to convert potassium permanganate (KMnO₄) to MnO₂. Subsequently, nanoflowers, quasi-spherical particles, broken, and interconnected chain type of morphology was observed by adding dispersion of 0.5, 1.0, 1.5, and 2.0 ml CDs in acetone to 1 mmol KMnO₄ aqueous solution in the corresponding MnO₂/CDs-0.5, MnO₂/CDs-1.0, MnO₂/CDs-1.5, and MnO₂/CDs-2.0 composites, respectively. A plausible mechanism on the transformation of morphology of MnO₂/CDs with CDs concentration is also provided. Further, the present work also focused for the first time on the application in the electromagnetic interference (EMI) shielding of MnO₂/CD nanocomposites due to the high dielectric and conductivity. Interestingly, MnO₂/CDs-2.0 (nanochains) exhibited the highest total EMI shielding efficiency (SE_T) of ~39.4 dB following reflection as dominant shielding mechanism due to the high aspect ratio, highest conductivity, high dielectric loss, and impendence mismatch.

Here, we report the structural and electronic modification induced in chemical vapor deposited graphene by using swift heavy ions (70 MeV Ni⁶⁺).Raman spectroscopy was used to quantify the irradiation-induced modification in vibrational properties. The increase in defect density with fluence causes an increase in the intensity ratio of its characteristic Raman D and G band. The increase in defect density also results in a decrease in crystallite size. The changes in the crystal structure are observed from X-rays diffraction measurement. Swift heavy ion irradiation induced defect, modified the surface roughness and surface potential of graphene thin film as measured from atomic force microscopy and scanning Kelvin probe microscopy respectively. The increase in the work function, surface roughness as well as defect concentration with fluence, indicate the possibility of linear correlation between them. Presence of defects in graphene sheets strongly affects surface electronic and optical properties of the material that can be used to tailor the optoelectronics device performance.

In the present study, combustion technique is adopted to study the impact of Mg²⁺ ion doping on ZnAI₂O₄ nanoparticles (NPs). L-arginine is used as a fuel component. The Mg²⁺ ions play a pivotal role in persuading various characteristics of ZnAI₂O₄ NPs. Various characterization technqiues such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), high resolution scanning electron microscopy (HR-SEM), diffuse reflectance spectroscopy (DRS), Thermo-gravimetric/differential thermal analysis (TG-DTA) and vibrating sample magnetometer (VSM) were carried out in order to synthesize the nanoparticles. Single phase cubic spinel structure of ZnAl₂O₄ (gahnite) formation was confirmed from the XRD characterization process of the nanoparticles. Estimated average crystallite size range of 11.85 nm to 19.02 nm was observed from Debye-Scherrer. Spherical morphology with uniform distributions was observed from HR-SEM characterization images. From the band gap studies, the attained band gap values were found to lie within 5.41 eV-4.66 eV range. The ZnAl₂O₄ and Mg:ZnAl₂O₄ NPs exhibited super-paramagnetic nature confirmed by magnetic measurements. The obtained results make ZnAl₂O ₄and Mg:ZnAl₂O₄ NPs appropriate for various optical, catalytic, energy and data storage applications.

Carborane are widely applied in boron neutron capture therapy (BNCT) field, but it is difficult to perform biocompatibility with cells due to its own water solubility differences, so how to solve the water solubility problem has always been the focus of research. A simple, inexpensive and effective method was used to study the synthesis of nido-carborane azaspirodecanium poly(carboxybetaine methacrylate) by one-pot cyclization of nido-carborane azaspirodecanium under the synergistic effect of inorganic bases and conventional organic solvents. Its characterization is mainly to use 1H-NMR nuclear magnetic resonance spectrum and infrared spectroscopy to determine the characteristic peak and range of borane. Through transmission electron microscope (TEM), it can be observed that the white nanoparticles, namely carborane, are completely contained by polymer ions, which not only increases the surface area but also the concentration of boron uptake in the cell is 100 times that of borono-phenylalanine (BPA). Based on the successful synthesis of N-CB5-4 and N-CB6-5 without harsh conditions, a feasibility point of view was put forward, namely, super water-soluble carborane polymer.

As a fullerene derivative, IC₇₀BA is widely used in the ternary organic solar cells (TOSCs) to increase the open circuit voltage (V_oc) of the devices. Unfortunately, most of the literature shows that IC₇₀BA will lead to a reduction in the short-circuit current density (J_sc) and fill factor (FF). In this work, IC₇₀BA is added to the PTB7:PC₇₀BM binary system to form the ternary system, which is composed of one donor and two fullerene acceptors. Surprisingly, the addition of IC₇₀BA does not immediately lead to a decrease in J_sc and FF. In fact, the appropriate weight ratio of IC₇₀BA in fullerenes can simultaneously increase the V_oc, J_sc, and FF of the TOSCs. The synergistic optimization of the surface and bulk morphology of the ternary active layer suppresses the attenuation of J_sc and FF. The smooth surface and suitable phase separation size effectively guarantee the separation, transport and extraction of the charge. Moreover, the addition of IC₇₀BA can significantly improve the hole transport capacity of the active layer, and the optimal hole mobility is 5.13 - 10"4 cm²V^-1S^-1. Finally, the TOSCs with 10% weight ratio of IC₇₀BA gives the optimal PCE of 9.24% and ideality factor of 2.3.

In the present study, we aimed to investigate the catalytic role of the newly reported MCM-41 -based nanocomposite in which the low acidity of this mesoporous moiety was favourably improved via the stabilization of zirconium nanoparticles and was magnetized to make a facile work-up procedure as an applicable and efficient method. The prepared Fe₃O₄@MCM-41 @ZrCI₂ nanocomposite was successfully characterized using different analyses and then it was favourably exploited for the synthesis of spirooxindoles as the most prominent spiro compounds. As predicted, Fe₃O₄@MCM- 41 @ZrCI₂ showed considerable efficiency in the promotion of the studied reaction.

Substantial attempts have been undertaken for the improvement of the air quality over decades; and Volatile Organic Compounds (VOCs) from the chemical and textile industries are truly listed as severe issue to be controlled. To come up with modus operandi for this issue, a novel composite of metal organic frameworks (MOFs) MIL-100(Fe) with salient tuned features of natrite was designed by a green and facile method. Mineralized composite MOFs exhibited enhanced crystallinity than pure MIL-100(Fe) as well showcased a higher surface area of 1300 m² g^-1. Through dynamic acetone pressure swing adsorption setup, MIL-0.05Na (MIL-100(Fe) synthesized with 0.05 mM Na₂CO₃ solution) revealed an enhanced acetone adsorption of 210 mg g ¹ at room temperature. Gas phase adsorption isotherms confirmed the mono layer adsorption behavior. The kinetics models evaluated that the external mass transfer was the rate limiting step for surface adsorption. The thermodynamic study manifested that the adsorption reaction was spontaneous and exothermic. The proposed mechanism of adsorption was the act of physisorption which enriched the adsorbents reusability. This research work provides a futuristic vista to design mineralized Fe-MOFs composites for an energy saving adsorbents for VOCs removal.

In this study, guesthost inclusion complexes of silver abietate with β-cyclodextrin were prepared by kneading and physical mixing techniques, and analyzed via fourier transformed infrared spectroscopy (FTIR) and thermogravimetric analyser (TGA). The 1:1 and 1:2 stoichiometry of the guesthost were prepared. Obtained FTIR and TGA results showed that formation of silver abietate:β-cyclodextrin (Ag-A:β-CD) inclusion complexes occurred at a mass ratio of both 1:1 and 1:2. Furthermore, prepared Ag-A:β-CD (1:2) inclusion complex was doped in Poly(vinyl alcohol) nanofibers during electrospinning process for obtaining nanowebs. The formation of nanowebs were investigated under scanning electron microscope (SEM), X-Ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR) and thermogravimetric analyser (TGA). The results confirmed Ag-A:β-CD inclusion complex containing Poly(vinyl alcohol) (PVA) nanoweb production.

In the present work, degradation of methylene blue (MB) dye in aqueous solution through H₂O ₂and iron doped g-C₃N₄ (Fe-g-C₃N₄) was studied. The hybrid was fabricated by thermal polymerization with iron (III) nitrate nonahydrate and melamine, and it was characterized by X-ray diffraction, Fourier transform infrared, UV-Vis diffuse reflectance spectrum, X-ray photoelectron spectroscopy, transmission electron microscope and Brunner-Emmet-Teller. The various experimental conditions such as doping amount, a dose of the sample, solution pH, the addition of H₂O₂, and concentration of MB on the degradation of MB dye were optimized. The maximum extent of degradation of methylene blue was obtained at pH 5, doping amount of 2.7 wt% and dose of 0.07 g. The molar ratio of Fe:H₂O₂ is 1:1000 showed 99% of MB (30 mg/L) decolorization over 60 min. The hybrid showed good stability and recyclability after three cycles of use. Photo-Fenton reaction exhibited a higher synergetic effect than the combination of Fenton and photocatalytic process.

In the present work, pure nanocrystalline monoclinic Zirconia (ZrO₂) has been successfully synthesized and optimized by the modified co-precipitation method. The concentration of raw material has been optimized with the fixed amount of precipitation agent (Potassium hydroxide KOH). The thermal history of the precursor has been examined through TG/DTA analysis. All the samples are subjected to study the structure, fingerprints of the molecular vibrations, and morphology analyses. The representative sample has been analyzed through Transmission Electron Microscope (TEM) and X-ray Photo Electron Spectroscopy (XPS) analyses. The as-prepared sample exhibits the better crystallinity and surface morphology with lesser particle size (190 nm) when the raw material concentration is 0.2 M. The as-prepared ZrO₂ filler (0, 3, 6, 9, and 12 wt.%) is spread through the enhanced polymer electrolyte P(S-MMA) (27 Wt.%)-LiClO₄ (8 wt.%)-EC + PC (1;1 of 65 wt.%) complex system via solution casting method. The as-synthesized electrolyte films are examined via complex impedance analysis. P(S-MMA) (27 wt.%)-LiCIO₄ (8 wt.%)-EC + PC (1 ;1 of 65 wt.%)-6 wt.% of ZrO₂ shows the high ionic conductivity 2.35 × 10^-3 Scm^-1. Temperature-dependent ionic conductivity studies obey the non-linear behavior. The enhanced ZrO₂ has been expected to enhance the other electrochemical properties of the lithium secondary battery.