Search

Waste water remediation is the ongoing hot research topic that can reduce the water scarcity all over the world. By reducing the pollutants in the waste water drawn from industries and other sources will be more useful for domestic purposes. To reduce the rate of pollutants in water may also help in improving the aquatic environment and decreases other side effects. Efficient and cost effective catalysts were in search for both dye degradation and water remediation treatment applications. NiMoO

Electrochemical energy storage is a current research area to address energy challenges of the modern world. The Cu2FeSnS4/PVP/rGO-decorated nanocomposite using PVP as the surface ligand was explored in a simple one-step solvothermal route, for studying their electrochemical behavior by designing asymmetric hybrid supercapacitor devices. The full cell three-electrode arrangements delivered 748 C/g (62.36 mA h/g) at 5 mV/s employing CV and 328 F/g (45.55 mA h/g) at 0.5 A/g employing GCD for the Cu2FeSnS4/PVP/rGO electrode. The half-cell two-electrode device can endow with 73 W h/kg and 749 W/kg at 1 A/g energy and power density. Furthermore, two Cu2FeSnS4/PVP/rGO//AC asymmetric devices connected in series for illuminating a commercial red LED more than 1 min were explored. This work focuses the potential use of transition-metal chalcogenide composite and introduces a new material for designing high-performance supercapacitor applications.

The polyhedron-structured NiSe

Molybdenum disulphide (MoS

The photocatalytic dye degradation of pure α-Fe

The tight focusing properties of an azimuthally polarized Bessel Gaussian beam phase modulated by annular Walsh function filter is studied numerically by vector diffraction theory. It is observed that upon suitable optimization of order and annular obstruction ratio of an annular Walsh function filter, one can generate multiple sub wavelength scale optical tubes (optical holes) with super long focal depth. Such a focal system is usable for Nano-lithography, particle trapping and transportation, as well as confocal and STED microscopy, microstructure fabrication etc.

In this study, P25-titanium dioxide (TiO2) was doped with ruthenium (Ru) by systematically varying the Ru content at 0.15, 0.30, 0.45 and 0.6 mol%. The synthesized Ru-doped TiO2 nanomaterials have been characterized by X-ray diffraction (XRD), Raman spectroscopy, energy-dispersive X-ray (EDX) analysis, UV-visible (UV−Vis) spectroscopy, and electrochemical impedance (EIS) spectroscopy. The XRD patterns of undoped and Ru-doped TiO2 nanomaterials confirm the presence of mixed anatase and rutile phases of TiO2 while EDX spectrum confirms the presence of Ti, O and Ru. Further, UV-visible absorption spectra of doped TiO2 nanomaterial reveal a slight red shift on Ru-doping. The short circuit current density (JSC) of the cells fabricated using the Ru-doped TiO2 photoanode was found to be dependent on the amount of Ru present in TiO2. Optimized cells with 0.3 mol% Ru-doped TiO2 electrodes showed efficiency which is 20% more than the efficiency of the control cell (η = 5.8%) under stimulated illumination (100 mWcm−2, 1 sun) with AM 1.5 filter. The increase in JSC resulted from the reduced rate of recombination upon doping of Ru and this was confirmed by EIS analysis.

In this study, a facile synthesis of chemical and thermal activation of biomass tea-waste materials was explored. A tea-waste biosource carbon was explored by chemical vapor deposition (CVD) method at 700 °C. The KOH-treated carbon (AC-KH) and H3PO4-treated carbon (AC-HP) were systematically studied for morphological characteristics and showed good morphological structures and a few transparent focused layered nanosheets. The elemental analysis done by scanning electron microscopy with energy-dispersive X-ray spectroscopy confirmed the presence of activated carbon. Fourier transform infrared spectroscopy (FT-IR) showed carbon-containing functional groups. The electrochemical analysis showed cyclic voltammetry (CV) curves for electric double layer capacitance (EDLC) with 3 M KOH electrolyte. The Nyquist plot obtained using electrochemical impedance spectroscopy (EIS) showed charge transfer resistance value (Rct) of 6.08 Ω. The electrochemical galvanostatic charge-discharge (GCD) study was conducted to obtain the specific capacitance (Scp) values of AC-KH, which were found to be 131.95 F/g at 0.5 A/g and also AC-HP active material was observed 55.76 F/g at 1 A/g. The AC-KH showed superior electrochemical performance when compared to AC-HP material. Hence, AC-KH is a promising active material for high-energy supercapacitor applications.

A facile synthesis of pristine and g-C3N4 loaded CdWO4 (Cadmium Tungstate) were reported and analyzed the effect of pollutants removal in wastewater. The samples were characterized and the morphology of the pristine sample showed the nanostructures with high cluster of layer formed. While adding PEG (Polyethylene glycol), the surface has exhibited less agglomeration and in g-C3N4 added sample the agglomeration was intensely reduced and nanostructures have been clearly found. Photocatalytic performance on cationic dye was investigated under visible light. The efficiency calculated for g–C3N4– CdWO4 sample was 85% for MB. The C/C0 plot gives better degradation. The kinetic study revealed pseudo first order reaction. The g–C3N4–CdWO4 sample exhibited higher “k” value which proved best efficiency on removing the pollutant. g–C3N4–CdWO4 sample will make better reduction on toxic pollutants and be a good candidate in futuristic applications. By carbon based derivates inclusion with photo active materials, the morphology and surface area was greatly improved and it enhances activity of host material and it will be the promising material for industrial applications.

Pristine and polyethylene glycol assisted antimony tungstate (Sb2WO6) was developed via hydrothermal route. The pristine and surfactant assisted Sb2WO6 were further exemplified to reveal the properties of the samples. The bandgap calculated for Sb2WO6, 5 ml PEG- Sb2WO6, 10 ml PEG- Sb2WO6 was 2.78 eV, 2.66 eV and 2.21 eV. The 10 ml PEG assisted sample exhibited narrow bandgap. The Fourier transform infrared spectroscopy (FTIR) spectra of the samples showed metal vibrations and stretching of the water molecules adsorbed. The Raman spectra showed the vibrational modes present in Sb2WO6. The morphology was analyzed employing transmission electron microscope (TEM) for all samples. Pristine Sb2WO6 showed growth of nanorods with higher dimensions with high agglomeration. 5 ml PEG- Sb2WO6 showed the growth of nanorods with lesser agglomeration. 10 ml PEG assisted Sb2WO6 exhibited distinct growth of nanorods with no agglomeration on the surface. The elemental composition was examined employing X-ray Photoelectron Spectroscopy. Prepared product photocatalytic behaviour was tested employing Rhodamine B dye degrading. Different catalyst loading were investigated for degrading the toxic pollutants. 0.2 g 10 ml PEG-Sb2WO6 showed 81% efficiency on degrading the toxic pollutant from wastewater. The OH radicals are accountable for photocatalytic behaviour of prepared photocatalyst. The 10 ml PEG-Sb2WO6 has the good reusability behavior and stable properties after three cycles. The prepared 10 ml PEG- Sb2WO6 photocatalyst will be the potential candidate for the remediation of the water treatment.

Hydrogen evolution reaction (HER) is a significant half reaction in water splitting and it is spirit of energy storage and conversion applications. Recently, high durability and catalytic activity of effective electrodes are necessary to enlarge clean and sustainable energy sources. However, overcoming the overpotential and to improve HER and OER performance is still one of the complicated tasks. Hence, in this present work, gadolinium (Gd) doped cerium oxide (CeO2) was successfully synthesized through a facile co-precipitation method. High intense peak at 28.5° clearly indicated CeO2 cubic structure formation identified by using X-Ray diffraction. The optical phonon mode of F2g and oxygen vacancies mode was detected by using Raman spectra. The optical properties of CeO2 were detected with help of photoluminescence spectroscopy (PL). Fourier-transform infrared (FTIR) spectroscopy confirmed Ce-O vibration of CeO2 crystal existence. Surface morphology of CeO2 was thoroughly studied by using SEM images. HER and OER activity of pristine and Gd doped CeO2 was thoroughly investigated with the help of linear sweep voltammetry. Compared to pristine CeO2, high content of Gd doped CeO2 exhibited excellent HER and OER activity with low overpotential (99 mV for HER and 369 mV for OER) and small Tafel slope (211 mV/dec for HER and 183 mV/dec for OER). Addition of rare earth metal influenced the structural and catalytic properties of optimized metal oxide. Hence, the incorporation of Gadolinium in CeO2 plays a crucial role to enhance both HER and OER performance and it is one of the good candidates for energy conversion applications.

Treatment of wastewater for reuse is an important strategy undertaken to deal with water scarcity. In this study, pure and La-doped barium ferrites were produced using a facile hydrothermal technique. Lanthanum was doped at 1% and 2% molar ratio and the obtained product was analyzed for further confirmation of crystal structure, optical properties, vibrational properties, and morphology. X-ray powder diffraction pattern confirmed material formation. Bandgap energies were estimated from a Tauc plot. The vibrational properties of the pure and doped samples were examined by Fourier-transform infrared spectra. The pure barium ferrite sample showed a spherical agglomerated morphology. The 1% La-doped barium ferrite sample showed reduced agglomeration and the particles were attached together. The 2% La-doped barium ferrite sample showed small nanoballs with no agglomeration on the surface. The transmission electron microscopy images confirmed no agglomeration for the 2% La-BaFe2O4 sample. The M–H loop revealed the ferromagnetic behavior of the pristine and doped samples. The 2% La-BaFe2O4 sample had 24.53 m2/g surface area. The photocatalytic activity was examined employing degrading methylene blue under ultraviolet (UV) and visible light. Prepared product showed better efficiency on UV light exposure. The 2% La-doped barium ferrite sample exhibited almost 80% of efficiency under UV light and 85% efficiency under visible light toward toxic pollutants. The sample attained 0.02 min−1 rate constant value. The main advantage of ferrite samples is that the particles can be separated by magnetic methods and the water will be fit for reuse. The sample will be a promising candidate for use in the wastewater treatment.

Here, we have introduced a facile solid-state route assisted method to prepare CH3NH3PbI3 perovskite nanoparticles (PNs) and together with a facile - powder press technique, for the deposition of prepared PNs - a solution cum vacuum-free route. The perovskite layer was prepared using different lead iodide (PbI2) precursor molar concentrations (0.5, 1, 1.5, 2 mmol) and the PbI2 concentration was found to have a significant impact on the structural, optical, morphological and electrical properties. The sample prepared using molar ratio PbI2: MAI at 1:3 shows the optimal bandgap value (∼1.51 eV), broader band edge peak at 755 nm and found have good optical property for photovoltaic (PV) applications. The J–V performance of the fabricated perovskite device with FTO/c-TiO2/mp-TiO2/Perovskite/CuI/ Cr/Pt-coated FTO counter electrode has been studied. The device fabricated using the concentration at PbI2:MAI 1:3 achieved a PCE of 3.9% and resulted in better long-term stability with deterioration in η and VOC by 27.87% and 29.23% after 15 days.

We demonstrate by means of first-principle calculations that the band structure of TlBiS2 characterizes this material as a promising candidate for photovoltaic applications. Two calculation hybrid functional models are used, one including the spin-orbit coupling and one neglecting it. These calculations show that TlBiS2 has a direct band gap of 1.10 eV in the absence of spin-orbit coupling and 0.67 eV for spin-orbit coupling. The absorption peaks appear in the visible region with a consequently high absorption intensity for both without and with spin-orbit coupling. We show how computational modeling of TlBiS2 can substantially enrich the understanding of photovoltaic properties.

Mosquito-borne diseases cause several deaths every year in tropical and subtropical climate countries. Control of vectors is an alarming problem in today’s world due to the resistance matters. In this study magnesium incorporated hydroxyapatite nanoparticles have been synthesized by microwave irradiation method. Magnesium chloride hexahydrate (MgCl2·6H2O) calcium nitrate tetra hydrate (Ca (NO3)2·6H2O) and disodium hydrogen phosphate (Na2HPO4) were used as magnesium, calcium and phosphorous sources to prepare hydroxyapatite nanoparticles. The FT-IR studies show the presence of hydroxyl and phosphate functional groups. The structural properties have been studied using X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Transmission Electron Microscope (HRTEM). The energy dispersive X-ray analysis (EDAX) revealed the presence of Ca, Mg, P and O in the prepared samples. The antibacterial activity of the as-synthesized nanoparticles was evaluated against two prokaryotic strains, the gram negative bacteria Escherichia coli for three different concentrations of as-synthesized nanoparticles and they showed excellent antibacterial activity. The as-synthesized Mg-HAp nanoparticles were tested against fourth instar larvae of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus and the nanoparticles exhibited significant mortality against the selected mosquitoes. The observed results suggest that the magnesium incorporated hydroxyapatite nanoparticles have the potential to be used as an effective mosquito larvae control agent against Ae. aegypti, An. stephensi, and Cx. quinquefasciatus. From the detailed literature review it has been observed that no work has been carried out so far on the larvicidal activity using hydroxyapatite (HAp) nanoparticles and magnesium substituted hydroxyapatite (Mg-HAp) nanoparticles. Keywords: Microwave irradiation method, Hydroxyapatite, Nanoparticles, Antibacterial activity, Prokaryotic strains, Larvicidal activity

Sol gel dip coating method has been used for preparing ZnO nanorods. ZnO nanorods have been sensitized using CdSe quantum dots by simple chemical method. Uniform coverage of quantum dots on ZnO nanorods is observed. The structural, optical and morphology of the ZnO nanorods, CdSe quantum dots and CdSe quantum dot sensitized ZnO nanorods have been studied. The presence of CdSe quantum dots in ZnO nanorods based film is clearly seen in FESEM and TEM image and the elements Zn, O, Cd and Se present in the film was confirmed by EDAX analysis. FTO/CdSe quantum dot-ZnO nanorods/electrolyte/platinum structure based solar cell has been fabricated and the cell efficiency has been found to be 2.1%.

Kesterite type CZTS (Cu2ZnSnS4) thin films were deposited on Indium Tin Oxide (ITO) coated glass substrates by simple sol-gel method. X-ray diffraction (XRD) pattern showed the presence of crystalline kesterite phase, whereas the electron microscopic (FESEM) analysis established the 1D morphology of the CZTS films. Electrical studies revealed the interesting bistability phenomena of CZTS films. The current-voltage (I-V) characteristics showed two distinct paths for forward and reverse sweep directions. Conducting AFM (C-AFM) studies also supported the bistability phenomena of the CZTS films. Present study on electrical bi-stability of the CZTS thin films will help to understand the defects in the absorber materials and the photovoltaic performance of the CZTS device.

The present work reports about the low-cost inorganic nickel sulphide-carbon composite synthesized using the simple chemical method and to be used as hybrid hole extraction and as a counter electrode material for perovskite (CH3NH3PbI3)-based solar cells (PSCs). The structural analysis confirms the existence of nickel sulphide (NiS) crystalline phase composed of small-sized crystallites. The optimal bandgap values of the prepared perovskite (1.51 eV) and NiS (3.71 eV) materials found to be favorable in achieving the active absorbing and hole extraction properties in PSCs. The surface morphology of the nickel sulphide materials is found to be highly dependent on the NiS-carbon composition. The current density-voltage (J-V) results of the fabricated perovskite solar cells with nickel sulphide-carbon composite hole transporting layer (HTL) suggests that incorporation of commercial carbon paste into the nickel sulphide nanoparticles tends to promote the charge carrier transporting ability and resulted in yielding high power conversion efficiency (PCE) of 5.20%, when compared to that of the bare NiS (1.87%). The results show that this nickel sulphide-carbon composite can serve as an efficient dual role as an HTL to transport holes and as a conductive counter electrode for the planar heterojunction PSCs with the structure FTO/compact-TiO2/porous-TiO2/perovskite/NiS-carbon. So, nickel sulphide-carbon composite can be considered as an efficient replacement for the other unstable HTMs and high-cost metal counter electrodes used in PSCs.

Based on vector diffraction theory and inverse Faraday effect (IFE), the light induced magnetization distribution of a tightly focused azimuthally polarized doughnut Gaussian beam superimposed with a helical phase and modulated by an optimized multi belt complex phase filter (MBCPF) is analysed numerically. It is noted that by adjusting the radii of different rings of the complex phase filter, one can achieve many novel magnetization focal distribution such as sub wavelength scale (0.29λ) and super long (52.2λ) longitudinal magnetic probe suitable for all optical magnetic recording and the formation of multiple magnetization chain with four, six and eight sub-wavelength spherical magnetization spots suitable for multiple trapping of magnetic particles are achieved.

We present first-principle computational modelling of the perovskite CsSnxPb(1−x)I3 (x = 0, 0.5 and 1), aimed at increasing the efficiency of perovskite photovoltaics. Using density functional theory calculations with a hybrid functional, we predict that both CsPbI3 and CsSnI3 are stable structures with direct bandgaps, suitable for photovoltaic application. On the other hand, the stable structure of CsSn0.5Pb0.5I3 exhibits an indirect bandgap, which could work as a direct bandgap due to the short electron-hole distance. The results of this study demonstrates that through bandgap engineering, we can obtain larger photon absorption ranges and higher efficiencies for perovskite based photovoltaics.

The power conversion of perovskite solar cells has increased steadily and reached 22.1%, recently. This has led the researchers to study lead-free halide perovskite materials like Cs2SnI6 due to the toxic nature of lead used in the record-breaking organic-inorganic perovskite structures. Since the presence of an intermediate band in semiconductors leads to enhancement of efficiency of the solar cells, we have also investigated the electronic structure of Cs2SnI6, to find whether the intermediate band is likely to exist in the middle of the band gap. The computational results for the electronic band structure and density of states indicate that Cs2SnI6 contains an intermediate band (IB). Additional absorption peaks that appear in the optical spectra of this material presented in this paper explicitly confirm this. All these studies and the presence of an IB that we identified in Cs2SnI6 suggests that Cs2SnI6 may have high potential used as intermediate band solar cell material.

This study focuses on incorporating multi-walled carbon nanotubes (MWNT) in nanoporous titanium dioxides (TiO2) thin film for enhancing the performance of hybrid poly(3-hexylthiophene)(P3HT)/TiO2 solar cells. MWNTs were successfully incorporated in the nanoporous TiO2 electrodes either by systematically blending or dipping prior to the deposition of P3HT. Current density–voltage (J-V) characteristic of the corresponding fabricated devices showed that the short-circuit current density (JSC) and fill factor are strongly influenced by the amount of MWNT incorporated into TiO2 nanoparticles. Solar cells with optimum amount of MWNT incorporated by blending in nanoporous TiO2 layer showed a factor of two efficiency enhancement, mainly due to improvement in JSC compared to the corresponding control device. Further increment in MWNT reduces the efficiency mainly due to a sharp drop in fill factor and VOC, which can be attributed to shunting by excess amount of MWNTs. Devices with MWNT dip-coated TiO2 and polymer too showed enhanced efficiency over 2.5% under AM 1.5 illumination (100 mW cm−2), which is a factor of three higher than the corresponding control device.

Flower of Kigelia Africana constitute anthoyanin as a predominant flavonoid pigment and are responsible for absorption of light in visible region. In the present study, the extract of this flower is used as sensitizer for DSSC. Na-doped TiO 2 nanorods have been synthesized via one step hydrothermal method and used as photoanode. XRD analysis of Na-doped TiO 2 nanorod samples revealed the formation of single rutile phase structure. FESEM images revealed the formation of nanorods and overgrowth of nanoflowers on increasing the amount of the dopant. The photoelectric conversion efficiency of DSSC increased from 1.09% to 1.56% when compared to undoped TiO 2 based DSSC that exhibited an efficiency of 0.87%. A relatively high open circuit voltage was obtained because of nanorods structure and doping technique. The downward shift of flat band voltage with Na-doped TiO 2 improved the driving force for electron injection, leading to the enhanced photocurrent density.