Anil V. Ghule

Low cost flexible 3-D aligned and cross-linked efficient ZnFe2O4 nano-flakes electrode on stainless steel mesh for asymmetric supercapacitors

A simple and economic approach for growth of 3-D aligned and cross-linked ZnFe2O4 nano-flakes on a flexible stainless steel mesh (FSSM) substrate (300 mesh) using a rotational chemical bath deposition technique for fabricating efficient asymmetric supercapacitors is reported. The prepared ZnFe2O4 nano-flake thin film (ZnFe2O4/FSSM-300) as an anode in combination with Ni(OH)2/FSSM-300 as a cathode was used as an asymmetric supercapacitor. Furthermore, ZnFe2O4 nano-flakes were also grown on FSSM with a different mesh and designated as ZnFe2O4/FSSM-200, ZnFe2O4/FSSM-250 and ZnFe2O4/FSSM-300 for investigating the effect of mesh size on the morphology formation and their electrochemical performance. Amongst the samples, ZnFe2O4/FSSM-300 exhibited excellent supercapacitive properties, such as a higher specific capacitance (1625 F g−1 at 1 mA cm−2) and excellent cycle stability (8000 cycles, 97% retention), which was marginally higher than ZnFe2O4/FSSM-250 (545 F g−1 at 1 mA cm−2, 70% retention), ZnFe2O4/FSSM-200 (241 F g−1 at 1 mA cm−2, 56% retention) and other earlier reported ferrites. In addition, the fabricated asymmetric pseudocapacitor device delivered better performance with high specific capacitance (118 F g−1 at 5 mA cm−2), excellent cycle stability (8000 cycles, 83% capacitance retention) and high energy density (42 W h kg−1) even at higher power density (5 kW kg−1).

Mechanochemical growth of a porous ZnFe2O4 nano-flake thin film as an electrode for supercapacitor application

Herein, we are reporting a simple, economic, easy to handle, scalable and reproducible mechanochemical i.e. rotational chemical bath deposition (R-CBD) approach for the synthesis of well adhered nano-flake ZnFe2O4 thin films (NFs-ZnFe2O4) with uniform morphology on a stainless steel (SS) substrate, in comparison with nano-grain ZnFe2O4 thin films (NGs-ZnFe2O4) prepared using a conventional CBD approach. The influence of rotation on the evolution of the nano-flake morphology in NFs-ZnFe2O4 is also investigated. The porous NFs-ZnFe2O4 thin films demonstrated excellent pseudocapacitor properties with higher specific capacitance of 768 F g−1 at high current density of 5 mA cm−2, stability upto 5000 cycles (88% retention), higher energy density (106 W h kg−1) and power density (18 kW kg−1) compared to NGs-ZnFe2O4. The results were also found to be higher than those reported earlier for MFe2O4 based systems.

Rapid fabrication of carbon quantum dots as multifunctional nanovehicles for dual-modal targeted imaging and chemotherapy

Herein, we synthesized an S, N, and Gd tri-element doped magnetofluorescent carbon quantum dots (GdNS@CQDs) within 10min by using a one-pot microwave method. Our results showed that these magnetofluorescent GdNS@CQDs have excellent fluorescent and magnetic properties. Moreover, GdNS@CQDs exhibited high stability at physiological conditions and ionic strength. These magnetofluorescent GdNS@CQDs were conjugated with a folic acid, denoted as FA-GdNS@CQDs, for targeting dual modal fluorescence/magnetic resonance (MR) imaging. The in vitro and in vivo studies confirmed the high biocompatibility and low toxicity of FA-GdNS@CQDs. FA-GdNS@CQDs enhanced the MR response as compared to that for commercial Gd-DTPA. The targeting capabilities of FA-GdNS@CQDs were confirmed in HeLa and HepG2 cells using in vitro fluorescence and MR dual modality imaging. Additionally, an anticancer drug, doxorubicin, was incorporated into the FA-GdNS@CQDs forming FA-GdNS@CQDs-DOX, which enables targeted drug delivery. Importantly, the prepared FA-GdNS@CQDs-DOX showed a high quantity of doxorubicin loading capacity (about 80%) and pH-sensitive drug release. The uptake into cancer cells and the intracellular location of the FA-GdNS@CQDs were observed by confocal laser scanning microscopy. We also successfully demonstrated in vivo fluorescence bio imaging of the FA-GdNS@CQDs, using zebrafish as an animal model. STATEMENT OF SIGNIFICANCE In this manuscript, we reported a facial, rapid, and environmental friendly method to fabricate hetero atoms including gadolinium, nitrogen, and sulfur doped multi-functional magnetofluorescent carbon quantum dots (GdNS@CQDs) nanocomposite. These multifunctional GdNS@CQDs were conjugated with a folic acid for targeting dual modal fluorescence/magnetic resonance imaging. Additionally, an anticancer drug, doxorubicin, was incorporated into the nanocomposite forming FA-GdNS@CQDs-DOX, which enables targeted drug delivery. We have developed GdNS@CQDs with integrated functions for simultaneous in vitro cell imaging, targeting, and pH-sensitive controlled drug release in HeLa cells. Furthermore, we successfully demonstrated the use of this material for in vivo fluorescence imaging, using zebrafish as an animal model.

Facile synthesis of gold/gadolinium-doped carbon quantum dot nanocomposites for magnetic resonance imaging and photothermal ablation therapy

Composites of gold nanomaterials and imaging agents show promise in cancer therapy. Here we have demonstrated a rapid, facile, environmentally friendly, and organic solvent-free method for the synthesis of a gold/gadolinium-doped carbon quantum dot (Au/GdC) nanocomposite for magnetic resonance imaging (MRI) and photothermal ablation (PTA) therapy. The gadolinium-doped carbon quantum dots (Gd@CQDs) were synthesized using a one-pot, microwave-assisted method, and used as reducing and stabilizing agents to both form the Au/GdC nanocomposite and prevent its agglomeration. Formation of the Au/GdC nanocomposite is achieved by simple mixing of Gd@CQDs and a gold precursor, without the addition of any other reducing agents, surface passivating agents, surfactants, or organic solvents. The Au/GdC nanocomposite shows paramagnetism, surface plasma resonance in the near infrared region (NIR), and excellent photostability. Furthermore, it provides high longitudinal relaxivity (r1 = 13.95 mM-1 s-1), indicating its potential for use as a T1 contrast agent in MRI. Furthermore, in vitro and in vivo studies using HeLa cells and zebrafish embryos as cancer and animal cell models, respectively, confirmed the low toxicity and excellent biocompatibility of the Au/GdC nanocomposite. Notably, our results demonstrate the ability of the Au/GdC nanocomposite to efficiently destroy cancer cells using PTA. Therefore, this work reveals a simple and powerful strategy to fabricate an Au/GdC nanocomposite for MRI and photothermal ablation of cancer cells.

A sensing behavior synergistic liquid–liquid extraction and spectrophotometric determination of nickel(II) by using 1-(2ˊ,4ˊ-dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydropyrimidine-2-thiol: Analysis of foundry and electroless nickel plating waste water

ABSTRACT We report the sensing behavior of liquid–liquid extraction of nickel(II), which has been selectively determined from contaminated water samples by a simple UV-visible spectrophotometer. The method is based on synergistic extraction of nickel(II) by 1-(2ˊ,4ˊ-dinitro aminophenyl)-4,4,6-trimethyl-1,4-dihydropyrimidine-2-thiol [2ˊ,4ˊ-dinitro APTPT] with pyridine. Nickel(II) reacts with 2ˊ,4ˊ-dinitro APTPT and forms a green-colored complex at pH 9.2. In addition, the Ni(II) ions were detected with the naked eye with the ligand. The absorbance of the coloured complex was measured at 660 nm and the colored complex is stable for more than 48 h even in the presence of other competing ions. The system obeyed Beer’s law in the concentration range of 5–50 μg mL−1 of nickel(II) and the optimum range evaluated by Ringbom’s plot method is 10–40 μg mL−1 with an excellent linearity and a correlation coefficient of 0.999. The molar absorptivity and Sandell’s sensitivity of the extractive species were found to be 1.64 × 103 dm3 mol−1 cm−1 and 0.0585 μg cm−2 in the presence of pyridine, and 7.4 × 102 dm3 mol−1 cm−1 and 0.78 μg cm−2 in the absence of pyridine, respectively. The composition of nickel(II)-2ˊ,4ˊ-dinitro APTPT-pyridine was established by the slope ratio method, the mole ratio method and Job’s method of continuous variation. It was found that the metal:ligand:synergent (M:L:Sy) ratio is 1:2:2. To assess the precision and accuracy of the developed method, determinations were carried out at n = 5. The relative standard deviation of all measurements does not exceed 0.16%. Excellent selectivity was found towards the Ni(II) ion due to a specific complex formation between the Ni(II) ion and the organic ligand. In the extraction of Ni(II), several affecting factors, including the solution pH, ligand concentration, equilibrium time, initial Ni(II) ion concentration and foreign ions, were investigated and the applicability of the method was checked by the analysis of synthetic mixtures and alloys. The developed method was successfully used for the determination of nickel(II) from waste water effluents from the foundry region and the nickel plating industry (Kolhapur city). The results obtained by the developed method were also confirmed by AAS. We claimed from this study that Ni(II) could be successfully determined by the spectrophotometric method developed in the current work. The present work is obviously much simpler than the conventional method comprising multistep processes.

Biodegradable Nanocomposites for Energy Harvesting, Self-healing, and Shape Memory

This review aims to survey the rapidly expanding field of energy harvesting, self-healing, and shape-memory biodegradable composites by reviewing the major successful autonomic designs developed over the last decade. We have discussed the characterization of the composite and dispersion of the filler by different methods such as grafting, chemical modifications. Also, we have highlighted the recent work on polymers and blends, hydrogels of biocomposites and their controllable approach for adjusting desired properties. In addition to above, the design considerations critical to the successful integration of these components in the commercial applications have been discussed. These materials have huge demand in the development of robust modeling and design tools based on a fundamental understanding of the complex and time-variant properties of the material and mechanization structure in diverse environments. The potential directions for future advancement in this field are also discussed.

Enhanced electrocatalytic hydrogen generation from water via cobalt-doped Cu2ZnSnS4 nanoparticles

Herein, we adopted a novel noble metal-free Co-doped CZTS-based electrocatalyst for the hydrogen evolution reaction (HER), which was fabricated using a facile, effective, and scalable strategy by employing a sonochemical method. The optimized Co-doped CZTS electrocatalyst shows a superior HER performance with a small overpotential of 200 and 298 mV at 2 and 10 mA−1, respectively, and Tafel slope of 73 mV dec−1, and also exhibits excellent stability up to 700 cycles with negligible loss of the cathodic current. The ease of synthesis and high activity of the Co-doped CZTS-based cost-effective catalytic system appear to be promising for HER catalysis.

Biomass-Mediated Synthesis of Cu-Doped TiO2 Nanoparticles for Improved-Performance Lithium-Ion Batteries

Pure TiO2 and Cu-doped TiO2 nanoparticles are synthesized by the biomediated green approach using the Bengal gram bean extract. The extract containing biomolecules acts as capping agent, which helps to control the size of nanoparticles and inhibit the agglomeration of particles. Copper is doped in TiO2 to enhance the electronic conductivity of TiO2 and its electrochemical performance. The Cu-doped TiO2 nanoparticle-based anode shows high specific capacitance, good cycling stability, and rate capability performance for its envisaged application in lithium-ion battery. Among pure TiO2, 3% Cu-doped TiO2, and 7% Cu-doped TiO2 anode, the latter shows the highest capacity of 250 mAh g–1 (97.6% capacity retention) after 100 cycles and more than 99% of coulombic efficiency at 0.5 A g–1 current density. The improved electrochemical performance in the 7% Cu-doped TiO2 is attributed to the synergetic effect between copper and titania. The results reveal that Cu-doped TiO2 nanoparticles might be contributing to the enhanced electronic conductivity, providing an efficient pathway for fast electron transfer.