Gajanan Ghodake

Hierarchical 3D-flower-like CuO nanostructure on copper foil for supercapacitors

We report a trouble-free chemical synthesis of copper oxide (CuO) nanoflowers on flexible copper foil (Cu) and their use as electrodes for supercapacitors. Various characterization techniques, such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), and Brunauer–Emmett–Teller (BET) analysis, have been used to characterize CuO nanostructure. Supercapacitive properties show that CuO electrodes exhibit a high specific capacitance of about 498 F g−1 at 5 mV s−1, with a high energy density of 26 W h kg−1 in KOH electrolyte. Moreover, impedance analysis showed lower ESR value, high power performance, and an excellent rate as well as frequency response for the CuO electrodes. The excellent electrochemical properties of the CuO electrodes indicate that they have many potential applications in high-performance supercapacitors.

Influence of Mn incorporation on the supercapacitive properties of hybrid CuO/Cu(OH)2 electrodes

Here, we are presenting the effect of Mn doping on the supercapacitive properties of CuO/Cu(OH)2 hybrid electrodes. Briefly, Mn doped CuO/Cu(OH)2 (Mn:CuO/Cu(OH)2) thin films have been synthesized by a successive ionic layer adsorption and reaction (SILAR) method which are further characterized by different physiochemical techniques. Our results revealed the formation of hybrid CuO/Cu(OH)2 thin films with significant morphological deviation through Mn doping. Moreover, considerable positive effect of Mn doping on the electrochemical properties of hybrid CuO/Cu(OH)2 electrodes have been witnessed. Later, the results suggest that at 3% Mn doping in CuO/Cu(OH)2 electrodes with nanoflower-like nanostructures exhibits the highest specific capacitance. The maximum specific capacitance achieved for a 3% Mn:CuO/Cu(OH)2 hybrid electrode is 600 F g−1 at 5 mV s−1 in 1 M Na2SO4 electrolyte. Additionally, a Ragone plot confirms the potential of the Mn:CuO/Cu(OH)2 hybrid electrode for electrical energy storage applications.

Cytotoxicity and antibacterial assessment of gallic acid capped gold nanoparticles.

Cytotoxicity of nanoparticles needs to be examined for their biocompatibility and suitability in biomedical applications. Gallic acid method was used for the high concentration synthesis (1mM) of gold nanoparticles (AuNPs) having narrow size-distribution at ambient temperature (25°C). Gallic acid capped AuNPs were characterized by different techniques such as, UV-vis spectroscopy, TEM, EDAX, SAED, and XPS. In-vitro stability of AuNPs with biomolecules, such as glucose and bovine serum albumin (BSA) was explored at different concertation ranges. The result reveals that AuNPs are biocompatible with normal cell line mouse embryonic fibroblast (MEF) cells up to 100ppm and cell viability can be retained more than 50% even after increasing the dose from 200 to 400ppm. Antibacterial application of AuNPs revealed that both particles and surface chemistry seems to be safer for both gram positive and gram negative bacterial cultures.

Electronic impurities (Fe, Mn) doping in CdSe nanostructures for improvements in photoelectrochemical applications

CdSe nanostructures (NSs) were tuned using different dopants (Fe:CdSe and Mn:CdSe) on electro-synthesized photoelectrochemical cells with fluorine-doped tin oxide (FTO) coated glass and stainless steel substrates. Thin films were characterized for their structural, morphological, and photoelectrochemical characteristics. Their optical and semiconducting parameters were also analyzed to determine the suitability of these films for photoelectrochemical (PEC)/solar cell applications. X-ray diffraction (XRD) analysis revealed that the films are polycrystalline in nature and suitable for improved solar cell applications. Scanning electron microscopy (SEM) studies illustrated that the thin films were adhered to the substrate uniformly and dopants were involved in the formation of novel nanostructured composition. Optical studies showed that the films are of direct band gap. For all the films, the semiconductor parameter values were in the better range of other transition metal chalcogenides, confirming that undoped CdSe and Fe:CdSe, Mn:CdSe thin films are capable as solar/PEC cell materials.

Chemical synthesis of hierarchical NiCo 2 S 4 nanosheets like nanostructure on flexible foil for a high performance supercapacitor

In this study, hierarchical interconnected nickel cobalt sulfide (NiCo2S4) nanosheets were effectively deposited on a flexible stainless steel foil by the chemical bath deposition method (CBD) for high-performance supercapacitor applications. The resulting NiCo2S4 sample was characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and electrochemical measurements. XRD and X-ray photoelectron spectroscopy (XPS) results confirmed the formation of the ternary NiCo2S4 sample with a pure cubic phase. FE-SEM and HR-TEM revealed that the entire foil surface was fully covered with the interconnected nanosheets like surface morphology. The NiCo2S4 nanosheets demonstrated impressive electrochemical characteristics with a specific capacitance of 1155 F g−1 at 10 mV s−1 and superior cycling stability (95% capacity after 2000 cycles). These electrochemical characteristics could be attributed to the higher active area and higher conductivity of the sample. The results demonstrated that the interconnected NiCo2S4 nanosheets are promising as electrodes for supercapacitor and energy storage applications.

Recent developments in nanotechnology transforming the agricultural sector: a transition replete with opportunities

The applications and benefits of nanotechnology in the agricultural sector have attracted considerable attention, particularly in the invention of unique nanopesticides and nanofertilisers. The contemporary developments in nanotechnology are acknowledged and the most significant opportunities awaiting the agriculture sector from the recent scientific and technical literature are addressed. This review discusses the significance of recent trends in nanomaterial-based sensors available for the sustainable management of agricultural soil, as well as the role of nanotechnology in detection and protection against plant pathogens, and for food quality and safety. Novel nanosensors have been reported for primary applications in improving crop practices, food quality, and packaging methods, thus will change the agricultural sector for potentially better and healthier food products. Nanotechnology is well-known to play a significant role in the effective management of phytopathogens, nutrient utilisation, controlled release of pesticides, and fertilisers. Research and scientific gaps to be overcome and fundamental questions have been addressed to fuel active development and application of nanotechnology. Together, nanoscience, nanoengineering, and nanotechnology offer a plethora of opportunities, proving a viable alternative in the agriculture and food processing sector, by providing a novel and advanced solutions.

Tuning stable and unstable aggregates of gallic acid capped gold nanoparticles using Mg2+ as coordinating agent

High reducibility of gallic acid allows synthesis of small sized monodisperse gold nanoparticles (GNPs) at ambient temperature (25°C). Mg2+ rapidly interacts with the gallic acid ligands and suppresses the dispersion of GNPs therefore, causing a decrease in UV-vis absorbance intensity, and color change from red to blue. Thus, the colorimetric response of GNPs with Mg2+ was investigated by observing temporal quenching of UV-vis absorbance and precise tuning of fractal growth of GNP aggregates. Moreover, Mg2+ at concentrations as low as 200ppb can be detected using gallic acid ligand-mediated coordination chemistry which results quenching in UV-vis absorbance proportional to the exposure time. This gallic acid-based colorimetric sensor shown a great potential for the selective detection of pathologically important electrolyte Mg2+ without any interference from other cations Ca2+ and K+.

Chemical synthesis of flower-like hybrid Cu(OH)2/CuO electrode: Application of polyvinyl alcohol and triton X-100 to enhance supercapacitor performance

In this research article, we report hybrid nanomaterials of copper hydroxide/copper oxide (Cu(OH)2/CuO). A thin films were prepared by using a facile and cost-effective successive ionic layer adsorption and reaction (SILAR) method. As-synthesized and hybrid Cu(OH)2/CuO with two different surfactants polyvinyl alcohol (PVA) and triton-X 100 (TRX-100) was prepared having distinct morphological, structural, and supercapacitor properties. The surface of the thin film samples were examined by scanning electron microscopy (SEM). A nanoflower-like morphology of the Cu(OH)2/CuO nanostructures arranged vertically was evidenced on the stainless steel substrate. The surface was well covered by nanoflake-like morphology and formed a uniform Cu(OH)2/CuO nanostructures after treating with surfactants. X-ray diffraction patterns were used to confirm the hybrid phase of Cu(OH)2/CuO materials. The electrochemical properties of the pristine Cu(OH)2/CuO, PVA:Cu(OH)2/CuO, TRX-100:Cu(OH)2/CuO films were observed by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy technique. The electrochemical examination reveals that the Cu(OH)2/CuO electrode has excellent specific capacitance, 292, 533, and 443Fg-1 with pristine, PVA, and TRX-100, respectively in 1M Na2SO4 electrolyte solution. The cyclic voltammograms (CV) of Cu(OH)2/CuO electrode shows positive role of the PVA and TRX-100 to enhance supercapacitor performance.

A comprehensive review on green nanomaterials using biological systems: Recent perception and their future applications

Over the last few years, nanotechnology is increasingly developing in scientific sector, which has attracted a great deal of interest because of its abundant applications in almost all the areas. In recent times, green nanotechnology is a relative and multidisciplinary field that has emerged as a rapidly developing research area. This is serving as an important technique that spotlight on making the procedure which is clean, safe and in particular environtmentally friendly, in a gap with the currently employed methods such as chemical and physical methods for nanosynthesis. The present review recaps the existing knowledge on various biogenic synthesis methods relying on bacteria, fungi, yeast, algae, viruses and on using biomolecules. The green nanosynthesis refers to the employment of reducing and stabilizing agents from plants and other natural resources, to fabricate nanomaterials. The green synthesis method does not engage the use of exceedingly venomous chemicals or elevated energy inputs during the synthesis. Nanoparticles (NPs) with distinct shapes, sizes and bioactivity can be produced from the variations in the bio-reducing agents employed for nanosynthesis. Hence, this review article summarizes the present information regarding the biological methods which are employed to fabricate greener, safer, and environmentally sustainable nanosynthesis routes. This review mainly highlights the wide-scale fabrication of NPs via green synthesis for biomedical and agricultural applications.

Combined effect of inorganic salts with calcium peroxide pretreatment for kenaf core biomass and their utilization for 2,3-butanediol production

This study focuses on development of calcium peroxide (CaO2) pretreatment that removes major part of lignin but retaining most of sugar components of kenaf core powder (KCP) biomass. In chemical pretreatment, usually higher loss of biomass occurs which was less during this pretreatment strategy. Supplementation of inorganic salts; manganese sulfate (MnSO4) and cobalt chloride (COCl2) in CaO2 pretreatment resulted in maximum delignification of KCP relative to individual CaO2 pretreatment. Maximum glucose yield (98%) and hydrolysis yield (80.5%) was achieved after enzymatic hydrolysis (30 FPU/g of KCP) under optimized conditions. Analytical results proved effective lignin removal and significant destruction of KCP with this pretreatment strategy. Finally, utilization of KCP enzymatic hydrolysates by developed strain Klebsiella pneumoniae KMK05 resulted in maximum 2,3-butanediol (BDO) production (10.42 g/L) and BDO titer (0.385 g/g of sugar). BDO titer achieved with KCP derived sugars were found comparable with the mixture of standard sugars which is notable.