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Biosynthesis of nanoparticles employing plant extracts has become incredibly popular as a simple and environmentally benign alternative to chemical and physical methods for synthesizing nanoparticles. The present work reports a low-cost green synthesis of gold nanoparticles (GNP) using green tea leaf extract as a reducing and stabilizing agent. Synthesized nanoparticles were characterized by UV–Visible absorption spectroscopy and Energy-dispersive X-ray spectroscopy (EDX) to confirm the presence of GNP in the solution. Dynamic Light Scattering (DLS) analysis confirmed the particle size in the range of 43 nm. These biosynthesized GNP were studied to understand their catalytic role in photocatalytic degradation of methylene blue (MB) under daylight conditions.

Phase change materials (PCM) are commonly utilized materials in latent heat energy storage (LHES) systems. In the present study, Fe2O3 was incorporated into myristic acid. The composites were prepared by melting and mixing method. The acids dispersed with Fe2O3 were prepared to enhance the thermal properties of the PCM mixtures and heat transfer at various nanoparticle loadings of 1 wt%, 2 wt%, 3 wt%, and 4 wt% were investigated. It was observed from the experimental results that the duration of melting and cooling rates for PCM composites increased in all nano compositions with respect to the pure myristic acid. Fourier transform infrared spectrum confirmed higher chemical stability of the nanoenhanced phase change material.

Phase change materials (PCM) are commonly utilized materials in latent heat energy storage systems. In the present study, Fe2O3 was incorporated into the eutectic mixture of myristic acid and lauric acid. The composites were prepared by a melting and mixing method. Fourier transform infrared spectroscopy and dynamic light scattering results revealed the physicochemical properties of the eutectic mixture. Thermal analysis was performed on the optimized PCM mixtures with various Fe2O3 loadings of 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, and 5 wt.%. It is observed from the experimental results that the duration of melting and cooling rates for PCM composite with 4 wt.% Fe2O3 loadings was significantly improved, i.e., 85.72% and 78.31%, respectively, when compared to its pristine counterparts. These enhanced heating/cooling rates and thermal conductivity are attributed to the optimized impregnation of 4 wt.% Fe2O3 nanostructures into the eutectic mixture.

Phase change materials (PCM) are commonly utilized materials in the latent heat energy storage systems. However, they have the limitation of low thermal conductivities which leads to poor charging and discharging rates. Lauric acid dispersed with the iron oxide nanoparticle was tested for its thermal performance to characterize its phase change properties. Different compositions of lauric acid were formulated with varying concentrations of iron oxide ranging from 1 wt. % to 4 wt. % were investigated. From the thermal charging and discharging studies, it was observed that lauric acid with 4% had shown the maximum heat transfer rate. Also, the FTIR spectrum confirmed the chemical stability and uniform dispersion of nanoparticle in lauric acid even after several thermal cycles. Such, lauric acid nanocomposites embedded with the iron oxide could be potential candidates in PCM applications.

The thermal energy storage (TES) in phase change materials (PCMs) plays an important role in energy management systems. Paraffin has found wide range of applications as a PCM due to its unique thermal and physical properties. The present study reports about the synthesis of MoO3 nanomaterials using chemical method. MoO3 nanomaterial was diffused into paraffin wax in 0.5, 1, 1.5, and 2 weight percentages and thermal analysis was conducted. It was observed that 1.5 wt % doped PCM showed best enhancement in thermal performance with 20.28% and 35.71% improvement in heating and cooling cycles. The photocatalytic activity of synthesized nanocomposite was also evaluated by degradation of methylene dye under visible light irradiation. The photocatalytic degradation effectiveness of as synthesized nanocomposites has showed high photodegradation efficiency (93.83 %) of methylene blue under visible light radiation.

In this study, flower-like MoS2 nanospheres were synthesized via a facile hydrothermal route. The morphological and phase analysis confirmed the formation of polycrystalline MoS2 nanoflowers assembled by lamellar nanosheets. A novel shape-stabilized phase change material was fabricated by imprisoning different concentrations of MoS2 into myristic acid. It was observed from the experimental results that the duration of melting and cooling rates for PCM of 0.25 wt%, 0.5 wt%, 0.75 wt%, 1 wt%, 1.25 wt% increased as compared to pristine counterparts. 1 wt% had the highest heat transfer rate, with a value of 9.4% and 52.81% for melting and cooling, respectively. The result from analytical technique showed there was no chemical reaction between MoS2 and myristic acid even after multiple cycles. Since this unique MoS2 based composite has indicated good thermal reliability for latent-heat storage, and release, this composite can be considered as an appropriate PCM for thermal energy storage applications.

Nanoparticles-based sensors have many benefits in sensitivity and specificity over traditional sensors. Nanoparticles-based sensors have more specificity due to operation at a small scale and hence the new properties on that basis. A novel, simple and highly sensitive method for the identification of the spoiled milk was developed based on measuring the percentage of lactic acid in spoiled milk by a functionalized nanoparticles sensor. In the present study silver nanoparticles were synthesized by chemical method and functionalized with cysteine and histidine. The nanoparticles were characterized by Dynamic light scattering (DLS) and UV-Visible spectroscopy (UV-Vis). A distinct color change was observed by the addition of functionalized nanoparticle to spoiled milk. Amino acids are helping in binding of nanoparticles and lactic acid resulting in the aggregation of nanoparticle. With the increase in the lactic acid concentration, thereby depicting the color change.

2D Molybdenum disulfide (MoS 2 ) is one among the most significant transition metal dichalcogenides which is attracting a wide range of research interests due to its potential applications in a broad spectrum. Monolayer of MoS 2 shows a direct band gap in the range of 1.8 eV and its layer dependence related to the band structure addresses the perennial problems related to graphene. Its applicability in such a versatile spectrum makes it an interesting candidate of study and this review attempts to explain the structure, properties and different characterization methods of 2D MoS 2 .

Green-synthesized mesoporous-structures have widespread attention due to its environmentally-benign nature and numerous applications. Herein, we report the green synthesis of mesoporous iron oxide network using green tea extract. The morphological and phase analyses were evaluated and elucidated the formation of mesoporous-structure showing predominantly hematite-phase. Catalytic role of α-Fe2O3 was investigated in Fenton reaction for the removal of methylene blue dye to understand its significance in wastewater treatment. Keywords: Green-synthesis, Mesoporous, α-Fe2O3, Photocatalysis

The present study reports the electrospinning of commercially available polyaniline-carbon black composite to develop conductive nanofibrous mats using polyvinyl alcohol as a binder solution. This binder solution was sublimated at 230 � C to attain a complete conducting nanofiber network. The binder sublimation was confirmed using thermo gravimetric analysis (TGA). Ultra-violet visible spectroscopy was used to determine the refractive index values for porosity measurements. It was observed that the heat treatment reduced the fiber diameter from ∼ 250 nm to ∼ 160 nm and increased the porosity from 41 ± 1.2% to 70 ± 2%. The spatial specific conductance mapping using Scanning Electro-Chemical Microscopy showed that the presence of polyvinyl alcohol binder in polyaniline-carbon black composite could introduce percolation threshold. The heat-treated fibers showed four times increase in specific conductance values on removal of binder phase from the fiber structure. The role of nanoscaled Schottky barriers in determining conductive pathways through polymer by hopping mechanism and also along carbon black particles are also been proposed in this study.

A rice-shaped TiO2-ZnO composite was prepared by electrospinning a mixture comprising the precursors of TiO2 and ZnO in polyvinyl acetate polymer dissolved in N,N-dimethyl acetamide. The electrospun nanofibers upon heat treatment in air resulted in collapse of the continuous fiber morphology and the formation of the rice-shaped TiO2-ZnO composite. The TiO2-ZnO composite was then treated with dilute acetic acid under hydrothermal conditions to etch ZnO from the TiO2-ZnO composite to get coral-shaped anisotropic TiO2. The structural anisotropy of TiO2 produced by the selective etching of ZnO resulted in a high surface area of 148 m(2) g(-1) for the TiO2. The initial and final materials were characterized by scanning electron microscopy, transmission electron microscopy, Raman and XPS spectroscopies, powder X-ray diffraction and BET surface area measurements. The utility of the anisotropic TiO2 in photovoltaics and photocatalysis was explored. Dye-sensitized solar cells fabricated using the TiO2 showed a conversion efficiency of 6.54% as against 4.8% for a control experiment with the rice-shaped TiO2. The anisotropic TiO2 also showed good photocatalysis in the degradation of methyl orange dye and phenol.

Herein, we report the facile synthesis of two α-Fe2O3 nanostructures with different morphologies via an electrospinning technique using ferric acetyl acetonate as a precursor and polyvinyl acetate and polyvinyl pyrrolidone as the respective polymers. The as-electrospun metal oxide–polymer composite fibers were sintered at 500 °C to obtain two distinct nanostructures, denoted as nanograins and porous fibers throughout this manuscript. These crystalline nanostructures were characterized using powder X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX) and transmission electron microscopy (TEM). The characterization results elucidated the predominance of hematite (α-Fe2O3) with particle sizes of 21 and 53 nm, for the respective nanostructures. Electrophoretic deposition was carried out in order to fabricate thin film electrodes, which were then subjected to electrochemical analysis. Electrochemical characterization revealed that both of the fabricated electrodes exhibited excellent performance in 1 M LiOH electrolyte with specific capacitance values of 256 and 102 F g−1 for the porous fiber and nanograin structures, respectively, at a scan rate of 1 mV s−1 and excellent capacitance retention, even after 3000 cycles, thus making them promising electrode materials for energy storage devices.