Energy Dispersive Analysis By X-rays Research Articles

Ferric oxide/ammonium nitrate nanocomposite: novel catalyzed eco-friendly oxidizer with advanced decomposition kinetics

ABSTRACT Ammonium nitrate (AN) could serve as a green substitute for ammonium perchlorate (AP) in halogen-free oxidizers. However, AN faces issues with endothermic phase transitions, melting, and sublimation. Ferric oxide, a common catalyst for solid propellants, was used to catalyze AN. This study reports the synthesis of 5 nm colloidal ferric oxide particles, integrated into the AN matrix through co-precipitation. Energy dispersive analysis by X-rays (EDAX) confirmed the proper dispersion of the ferric oxide catalyst. The impact of ferric oxide on AN decomposition enthalpy was assessed using differential scanning calorimetry DSC. Virgin AN showed an endothermic decomposition enthalpy of +1708 J/g, while catalyzed AN showed exothermic decomposition of −732 J/g. Ferric oxide nanocatalyst offered a decrease in AN main decomposition temperature by 83°C using thermogravimetric analysis (TGA). Activation energy dropped significantly, from 87.3 to 16.8 KJ/mol (Kissinger model), due to ferric oxide’s catalytic effect involving ferric and ferrous ion reactions.

Influence of Nd3+ on structural, electrical and magnetic properties of Ni-Cd nanoferrites

Here in we report the nanocrystalline Ni1-xCdxNdyFe2-yO4 (0 ≤ x ≤ 1.0 in steps of 0.2: y = 0.0; 0.1) ferrites were synthesized by novel solution combustion technique. The sintered powders have been characterized by X-ray diffraction (XRD), Fourier transmission infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Energy dispersive analysis by x-rays (EDAX) methods. DC electrical conductivity carried out by two probe method. Magnetic parameters were measured using vibrating sample magnetometer with an applied magnetic field up to 15 kOe at 300K. The XRD results confirmed the formation of single phase cubic spinel structure formation. It was found that the lattice parameter increased with increase in Cd2+ ion. The crystallite sizes have been found in the range of 44.24 nm–15.467 nm. Moreover, the formation of two prominent absorption bands confirmed the spinel structure. The SEM micrographs evidenced almost spherical shaped, agglomerated and grainy structure of nanoferrites. Moreover, the Curie temperature (TC) was decreased with increasing temperature and exhibit the semiconducting behaviour. Further, saturation magnetization (MS), remanence magnetization (Mr); coercivity (HC) were decrease with increase in the magnetic field. The magnetic parameters; MS, Mr, nB increases attain maximum thereafter decreases with increase in Cd2+ ion and Nd3+ ion content.

ZnO doped C: Facile synthesis, characterization and photocatalytic degradation of dyes

Carbon doped ZnO nanoparticles have been synthesized from the thermal decomposition of Zinc citrate precursor. The precursor was synthesized from semi-solid paste and then subjected to calcination at 700 °C to produce ZnO nanoparticles. The precursor and ZnO were characterized by Fourier Transform Infrared Spectroscopy, UV–visible (UV–Vis) spectra, Transmission Electron Microscope, Field Emission Scanning Electron Microscope, Energy Dispersive Analysis by X-ray (EDAX), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results ensured the formation of hexagonal 2D-ZnO nanoparticles with a layer thickness of 25 nm. The optical band gap of ZnO was determined and found to be 2.9 eV, which is lower than the bulk. Photocatalytic degradation of Fluorescein dye as an anionic dye and Rhodamine B as a cationic dye was evaluated via C-ZnO NPs under UV irradiation. ZnO displayed 99% degradation of Fluorescein dye after 240 min and a complete photocatalytic degradation of Rhodamine B dye after 120 min under UV irradiation.

Characterization of Solid-Solution and Aging Process in Mg-5 wt.%Sn Alloy

Firstly, the properties and the microstructure evolution of the solid-solution process of Mg-5 wt.%Sn were studied. From the motion analysis of resistivity and microhardness during solution treatment, the reasonable solution technology of Mg-5 wt.%Sn should be 12–16 h at 480 °C. After solution treatment at 480 °C for 16 h, the precipitating behavior in supersaturated solid solution. Mg-5 wt.%Sn alloy was investigated. In the aging process, it was observed that there were precipitated phases in the both grain and grain boundaries, and continuous inhomogeneous precipitation occurred along the grain boundaries, and continuous homogeneous precipitation happened in the grain. Transmission Electron Microscope (TEM) analysis indicated the plate- and lath-shaped precipitates within the grains and only the plate-shaped precipitates along the grain boundary. High-Resolution Electron Microscopy (HRTEM) studies have shown that metastable precipitates may occur during aging, coherently or semi-coherent with the matrix. Energy Dispersive Analysis by X-ray (EDAX) analysis showed that the Mg/Sn ratio was not actually constant, and the Sn content of the metastable phase was lower than that of the Mg2Sn equilibrium phase. X-ray diffraction (XRD) studies confirm the existence of this metastable phase, which is supposed to be GP zone and metastable Mg3Sn phase.

Effects of Heat Treatment in Air Atmosphere on Dip Coating Deposited CdS Thin Films for Photo Sensor Applications

Objective: In this report, photo sensitive materials with enhanced charge carriers have been prepared using dip coating technique. Methods: Cadmium sulphide (CdS) is N-type semiconductor compound belonging to II-VI group. CdS nanoparticles were synthesized using non-aqueous chemical method and characterized by ultraviolet-visible (UV-Vis) absorption spectroscopy, photoluminescence (PL) and transmission electron microscopy. CdS films were deposited on fluorine doped tin oxide (FTO) glass slides using dip coating method at different dip times and heat treated in air and analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive analysis by X-rays (EDAX), mapping and atomic force microscopy (AFM). Results: Quantum confinement effect was observed in UV-Vis absorption spectra of CdS nanoparticles. Quenching of luminescence intensity and blue shift at smaller wavelengths were observed in PL spectra. Presence of highly dense rectangular shaped grains in CdS films and increment in particle sizes with increase in dip time were shown by AFM images. Selected area electron diffraction images showed ring patterns indicating polycrystalline nature of CdS nanoparticles. Increase in crystallite size and decrease in crystal defects by heat treatment in air and increment in grain size with increase in dip time were shown by SEM images. XRD analysis of CdS films showed polycrystalline nature. Conclusion: In previous work, preparation of dip coating deposited CdS films on FTO glass substrates for optoelectronic device applications such as photo sensors has not been reported. In this study, I-V characteristics of heterojunctions under dark and illumination conditions were discussed. Experimental results obtained in our study and their comparison with previous reports were also discussed.

High Photosensitivity Nanocrystalline p-Cu2S/n-FTO Heterojunction Photodetectors Prepared by Dip Coating Method

Objective: The aim of present work is to fabricate nanocrystalline p-Cu2S/n-FTO heterojunction photo detectors with high photosensitivity. Methods: Copper sulphide (Cu2S) is semiconductor compound belonging to I-VI group. Cost effective chemical method was used to synthesize thioglycerol capped Cu2S nanoparticles with improved optoelectronic and physical properties. These nanoparticles were investigated by ultraviolet-visible (UV-Vis) absorption spectroscopy, photoluminescence (PL) and transmission electron microscopy (TEM). Cu2S films were deposited on fluorine doped tin oxide (FTO) glass slides using cost effective dip coating method at different dip times and heat treated in air atmosphere. Wide band gap fluorine doped tin oxide, n-type semiconductor was used as transparent window material together with narrow band gap Cu2S, p-type semiconductor used as absorber layer in case of Cu2S/FTO heterojunction photo detectors under reverse biased mode and illumination. Results: Cu2S films were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Analysis by X-rays (EDAX), Mapping and Atomic Force Microscopy (AFM). Selected Area Electron Diffraction (SAED) images showed ring patterns indicating that Cu2S nanoparticles are polycrystalline in nature and spot patterns indicating that Cu2S nanoparticles are monocrystalline in nature. Conclusion: Previously, preparation of optoelectronic devices such as photo detectors using Cu2S films has not been reported. In this study, photo detectors having enhanced photosensitivity were prepared using Cu2S films. I-V characteristics of p-Cu2S/n-FTO heterojunctions under dark and illumination conditions were examined. It was observed that film conductivity decreases under dark condition and increases under illumination condition with increase in dip time in case of Cu2S/FTO heterojunction photo detectors.

Low-cost nebulizer spray deposited conduction mechanism of thin film ZnO nanoparticles

The Zinc Oxide (ZnO) thin films have been deposited on glass substrate at different temperature from 300 to 500 o C by nebulizer spray pyrolysis technique. The prepared films were characterized by X-Ray diffraction (XRD), High resolution scanning electron microscope (HRSEM), Energy dispersive analysis by X-rays (EDAX), Photoluminescence (PL), UV-Vis-NIR spectrometer and impedance spectroscopy, respectively. The XRD confirms that the films are polycrystalline in nature with hexagonal wurtzite crystal structure with (002) plane as preferential orientation. The various parameters such as crystallite size, micro strain, and dislocation density were calculated from X-ray diffraction. HR-SEM images show smooth, tiny grains and dense morphology. The PL studies exhibits two emission peaks one at 389 nm corresponding to band gap excitonic emission and another located at 490 nm due to the presence of singly ionized oxygen vacancies. The UV-Vis-NIR spectrometer confirms the possibility of good transparent ZnO films with an average transmission of about ~85-95% in the visible region and optical band gap shifted from 3.37 eV to 3.2 eV with increase in temperature and which is supported by PL study. The semiconductor bahaviour and activation energy of these films have been confirmed by impedance spectroscopy measurements.

Synthesis and characterization of nanoparticles of semiconducting metal suplhide and their application

Cadmium Sulphide (CdS) [II-VI group n-type semiconductor] and Copper Sulphide (Cu2S) [I-VI group p-type semiconductor] have large commercial applications like solar cell, gas sensor etc. Wide band gap CdS semiconductor was used as the transparent window material together with narrow band gap Cu2S semiconductor used as the absorber layer. Thioglycerol capped CdS and Cu2S nanoparticles were synthesized by using the non-aqueous chemical method at room temperature. CdS and Cu2S films were prepared on fluorine doped tin oxide (FTO) glass substrates by using the simple dip coating method at different dip times and heat treated in air. CdS and Cu2S nanoparticles were analysed by Ultraviolet-Visible absorption spectroscopy, photoluminescence (PL) and transmission electron microscopy (TEM). CdS and Cu2S films were investigated by scanning electron microscopy (SEM), energy dispersive analysis by x-rays (EDAX), mapping and atomic force microscopy (AFM). Thicknesses of films were determined using laser profilometer. Previously, preparation of solar cells using CdS and Cu2S films deposited by dip coating method has not been reported. In this study, thin-film solar cells with p-n heterojunction having enhanced conductivity, excellent solar energy conversion efficiency, enhanced fill factor, low cost and easy fabrication were prepared to increase the quality of solar cells.

Synthesis of Nanoparticles of Aluminium–Boron complex for Radiation Sensor

Radiation sensors based on thermo luminescence from nanoparticles of aluminium-boron complex for gamma radiation have been reported. Crystal chemistry of aluminium boride is quite complicated and is derived from complex tetragonal modification of boron. The crystal structure varies with the method of preparation and energy band gap contains defect states governed by the temperature during synthesis. There are various methods of preparing nanoparticles like boll milling, sol-gel and RF-thermal plasma. In the present studies Aluminum boron complex nanoparticles were synthesized by DC- transferred arc thermal plasma method. The DC-transferred arc thermal plasma has been received great attention as a useful method to synthesize nanoparticles. Since a substance is easily evaporated in large volume of thermal plasma. A pure aluminium and boron powders were mixed together and made to evaporate from water cooled graphite after impinging thermal plasma plume. Argon with flow rate of 3L/min was used as a plasma forming gas for the evaporation of raw powder mixture in Ar ambient in the plasma reactor. The obtained nanoparticles of aluminum –boron complex were characterized using X-ray diffraction technique for structural analysis, Transmission electron microscopy (TEM) for morphological analysis and energy dispersive analysis by X-ray (EDAX) for elemental analysis. The aluminum boron complex so obtained was investigated for thermoluminscence properties.

Confined space synthesis of chromium–based metal–organic frameworks in activated carbon: Synergistic effect on the adsorption of contaminants of emerging concern from water

The steadfast presence of contaminants of emerging concern (CECs) in the environment calls for tailored remediation strategies. In this regard, Cr-based metal-organic frameworks (MOFs; MIL-100Cr and MIL-101Cr) were grown inside of activated carbon (AC) pores via confined synthesis for a superior adsorptive removal of those CECs from water. The composites CMOF-100Cr and CMOF-101Cr, as well as the apohost AC and pure MOFs, were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive analysis by X-rays (EDAX), nitrogen adsorption–desorption, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy, and zeta potential measurements. XRD, SEM/EDAX, TGA, and pore size distribution data provided direct evidence of the successfully confined space syntheses of the hierarchical composites. Occupancy of the large voids of AC by the MOF was 100% and 43% for CMOF-100Cr and CMOF-101Cr, respectively. The adsorption capacity of the materials was evaluated in both single- and multi-component fashion at neutral pH and low CEC concentrations (μg L−1). The CECs were caffeine (CFN), carbamazepine (CBZ), clofibric acid (CA), naproxen (NPX), and metabolites 10,11-epoxycarbamazepine (Ep-CBZ), o-desmethylnaproxen (o-DMN), paraxanthine (PXN), and salicylic acid (SA). In general, the observed capacities for both single and multi-component adsorption of CECs increased as follows MIL-100Cr < < MIL-101Cr < CMOF-101Cr < AC < < CMOF-100Cr. Compared to the composite containing MIL-100Fe (i.e., CMOF-100Fe) previously developed by our group, the substitution of the metal node by Cr3+ produced significant enhancements in CEC uptake capacities. The affinity of CMOF-100Cr toward CECs increases as follow: SA < CA< o-DMN < NPX < PXN < CFN < Ep-CBZ < CBZ. Environmental significanceThe persistence of contaminants of emerging concern (CECs) in water mandates the development of tailored remediation strategies. To be suitable, these must consider efficacy and avoid undesired byproducts. An attempt to individually grow two chromium-based nanoporous metal-organic frameworks, each possessing particular linkers, within the pores of an activated carbon via confined space synthesis has proven to be effective in the adsorptive removal of a set of CECs that included metabolites. Furthermore, the adsorption was conducted in both single- and multi-component fashion to gain insight into the CECs competitive nature during uptake. The hierarchical composite adsorbents exhibited superior uptake capacity because of the synergistic combination of hydrophobicity and specific interactions between the metal node and the CECs, while multiple adsorption cycles were possible via thermal regeneration.

Electronic and optical studies of NbS2 semiconductor material

Temperature dependance of energy band gap of NbS2 semiconducting material was studied. NbS2 is an important class of two-dimensional semiconducting material with properties that enable its use in diverse areas. Electronic and optical properties of NbS2 are of particular interest and importance for applications in optoelectronics as light emitters, detectors, and photovoltaic devices. Energy dispersive analysis by X-ray (EDAX) was used to verify the compositional elements of NbS2 crystals. The absorption coefficient was determined at room temperature in the wavelength range 800–2000 nm. Optical parameters of NbS2 have been estimated. The direct optical energy gap was found as 1.550 eV. The temperature dependence of energy band gap in the temperature range (303–423 K) has been reported. Results obtained are represented and discussed.

Using the ash of common water reeds as a silica source for producing high purity ZSM-5 zeolite microspheres

Abstract Utilizing of ash extracted from Iraqi common water reeds as an inexpensive effective silica source in the preparation of ZSM-5 zeolite was investigated for the first time in the present work. This study was conducted using a hydrothermal treatment at autogenous pressure. The molar content of silica (17.84–26.76), sodium oxide (1.71–2.4), water (76.92–304.6), organic template (0.55–2.73), organic solvent (23.46–140.76), and synthesis conditions (crystallization time (24–72 h) and temperature (130–180 °C)) were investigated to obtain high purity ZSM-5 zeolite microspheres. The zeolite samples were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Analysis by X-Ray (EDAX), N2 adsorption/desorption isotherms, Thermogravimetric Analyzer (TGA), and Fourier transform infrared spectroscopy (FTIR). XRD pattern of all synthesized samples was compared to XRD pattern of the commercial ZSM-5 zeolite. This work allows using locally available solid waste resulted from a dry natural plant as an inexpensive silica source without using an external source of silica. Also, this is the first report of the direct synthesis of a high purity ZSM-5 zeolite microspheres from common water reeds ash containing highly reactive silica. A gel composition of 2Na2O: 26.76SiO2: Al2O3: 2.73TPAOH: 23.46EtOH: 304.6H2O gave an outstanding final product of ZSM-5 zeolite microspheres at 180 °C and 27 h. This high crystallinity ZSM-5 zeolite porous microspheres possess Si/Al ratio of 17, a crystal size of 61.419 nm, BET surface area of 277.482 m2/g, a total pore volume of 0.1659 cm3/g, micropore volume of 0.1131 cm3/g, pore width of 5.28 nm, and hierarchical factor of 0.14.

Photocatalytic Reduction of Fluorescent Dyes in Sunlight by Newly Synthesized Spiroindenoquinoxaline Pyrrolizidines.

Spiroindenoquinoxaline pyrrolizidines (SIQPs)—7-nitro-2′-phenyl-5′,6′,7′,7a′-tetrahydrospiro[indeno[1,2-b]quinoxaline-11,3′-pyrrolizine]-1′,1′(2′H)-dicarbonitrile (SIQP I), 2′-(4-cyanophenyl)-7-nitro-5′,6′,7′,7a′-tetrahydrospiro[indeno[1,2-b]quinoxaline-11,3′-pyrrolizine]-1′,1′(2′H)-dicarbonitrile (SIQP II), and 2′-(4-methoxyphenyl)-7-nitro-5′,6′,7′,7a′-tetrahydrospiro[indeno[1,2-b]quinoxaline-11,3′-pyrrolizine]-1′,1′(2′H)-dicarbonitrile (SIQP III)—have been synthesized through a one-pot cascade Knoevenagel condensation reaction in acetonitrile (ACN) with 91, 98, and 87% yields, respectively. Structures are characterized by 1H NMR and 13C NMR spectroscopy, nuclear Overhauser enhancement spectroscopy (NOESY), Fourier transform infrared (FT-IR) and UV–vis spectroscopy, thermogravimetric analysis (TGA), high-resolution mass spectroscopy (HRTEM), fluorescence and Raman spectroscopy, and energy-dispersive analysis by X-ray (EDX) spectroscopy. SIQPs in ACN photocatalyzed methylene blue (MB) but not phenolphthalein (HIn). SIQPs distinguished the quaternary atoms and dipoles of the fluorescent dye (MB) contrary to the quinonoid HIn structure. In sunlight, SIQPs without electricity input acted as a photonic sensor to detect fluorescent dyes in waste effluents of textile, paper, dyes, and other industries. Activation energy (Ea), enthalpy (ΔH), entropy (ΔS), and Gibbs free energy (ΔG) calculated from UV–vis absorption spectra show photocatalytic reduction (PCR) activities in the order SIQP II > III > I. The N-atom of pyrrolizidine and −NO2 of nitro-indenoquinoxaline (NIQ) induced the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO) electrodynamics to enable the SIQPs to catalyze biochemical activities.

Synthesis of hierarchically porous ZSM-5 zeolite by self-assembly induced by aging in the absence of seeding-assistance

Microspherical ZSM-5 zeolite possesses a hierarchical porosity with high crystallinity and an adequate surface area was successfully synthesized using the self-assembling method induced by aging in the absence of seeding-assistance, a mesoscale template and organosilanes. The structural properties of the hierarchically porous ZSM-5 zeolite were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive analysis by X-ray (EDAX) thermogravimetric analyzer (TGA), Fourier transform infrared spectrophotometer (FTIR) and nitrogen adsorption/desorption isotherms. The results showed that the formation of microspherical clusters of polycrystalline nanosized ZSM-5 by a conventional hydrothermal treatment at 170 °C in the range of crystallization time 40–72 h from colloidal silica in the absence of seeds. Aging is thought to be the key factor influencing the generation of the hierarchically porous ZSM-5 with a Si/Al ratio of 12.5, surface area of (86.0302 ± 2.1698 m2/g) and pore volume of (0.0684 cm3/g) via the self-assembling method in the absence of seeding-assistance, a mesoscale template and organosilanes. Also, ethanol was an essential element to direct the crystallization toward a favorable product with an outstanding shape and hierarchical porosity. Investigating the order of mixing confirms the importance of adding aluminates precursor to silicates precursor to gain MFI structure.

Sodium hydroxide mediated alumina nanoparticles from waste aluminum foil sheets – Biological impact and photo-catalytic efficacy on commercial dyes

Herein, we reported a one-pot facile synthesis of alumina nanoparticles using waste aluminum foil sheet and sodium hydroxide by a simple solution method. The synthesized alumina nanoparticles were examined by UV Visible, X-Ray diffraction studies (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive Analysis by X-rays (EDAX) to determine their size, shape, chemical nature and crystal structure. The average size of the alumina nanoparticles was found to be 50–70 nm. Besides the photocatalytic activity of alumina nanoparticles on two different commercial dyes, viz., MG and MB dyes were evaluated under UV light and naturally available daylight sources. The dye degradation percentages of MG dye under daylight irradiation are ∼17.7% and ∼94.8% under UV light irradiation, ∼14.8% and 90.1% for pure dye and alumina nanoparticles respectively. The percentage of degradation of MB dye in the presence of pure dye, alumina nanoparticles under daylight irradiation, and UV light irradiation are ∼19.6%, ∼92.6%, and ∼6%, 87.2% respectively. These results strongly authenticate the enhanced Photocatalytic activity due to efficient charge separation originating in the alumina nanoparticles. The alumina NPs exhibited an effective antibacterial activity against gram-positive and gram-negative bacteria and also showed an inhibition against human MCF-7 cancer cells, indicating its efficiency in the field of biomedical research.

Synthesis, Characterization and Gas Sensing Study of SnO2 Thick Film Sensor towards H2S, NH3, LPG and CO2

Abstract SnO2 is synthesized by microwave assisted technique. Crystal structure and particle size is studied by XRD. Particle size of synthesized sample is investigated by TEM, FE-SEM and Scherrer formula. Crystalline nature is observed by SAED. FE-SEM of sample is carried out for knowing surface morphology and particle size. Energy dispersive analysis by X-ray (EDAX) is done for studying elemental composition and their mass percentage in the sample. The thick film of SnO2 is fabricated by screen printing technique for exploring V-I characteristics and conductivity. The gas sensing response of SnO2 thick film sensor towards H2S, LPG, NH3 and CO2 is studied

Electrochemical atomic layer deposition of cadmium telluride for Pt decoration: Application as novel photoelectrocatalyst for hydrogen evolution reaction

Metal-chalcogenide nanomaterials, as compared to their wide bandgap counterparts, are particularly attractive photoelectrocatalytic materials for the conversion of solar energy into chemical energy under visible-light irradiation. In this study, the thin layer of CdTe was deposited on the surface of Au/ITO electrode using electrochemical atomic layer deposition. Deposition process was performed through the alternate under potential deposition of the Te and Cd elements with a monolayer at a time, respectively. The images of scaning electron microscopy (SEM) indicated that nanoparticles of CdTe well dispersed on Au/ITO with an average particle size about 15 nm. The results of energy dispersive analysis by X-rays (EDAX) confirmed the off-stoichiometric CdTe layer, which lead to Cd-rich CdTe because of tellurium vacancies in the deposition potential. The resulting Cd-rich CdTe/Au/ITO electrode was used for preparation of Pt/CdTe/Au/ITO by redox replacement reaction between Pt2+ and Cd excess in CdTe layer to form 1.76 wt% of Pt element which uniformly distributed on the surface of CdTe/Au/ITO. Chronoamperometric tests in sodium sulfide solution exhibited that the Cd-rich CdTe layer had n-type semiconductivity whereas the Pt/CdTe layer showed p-type semiconductivity. The Pt/CdTe/Au/ITO electrode showed higher photoelectrocatalytic activity for the HER as compared to a commercial Pt/C on Au/ITO. The onset potential for HER is almost similar and the overpotential at −10 mA cm−2 is 160 mV more positive on Pt/CdTe/Au/ITO under light illumination with respect to Pt/C/Au/ITO. The long-term stability tests under illumination in acidic solution revealed that Cd-rich CdTe and Pt/CdTe layeres have extremely high stablity for HER compared to Pt/C. The higher photocatalytic activity on Pt/CdTe/Au/ITO electrode for HER is attributed predominantly to the synergistic effect of Pt, which not only serves as co-catalysts for promoting electron transfer to the electrocatalyst-electrolyte interface, but also accelerates the HER.

Study of microstructural, morphological and optical properties of sprayed vanadium doped ZnO nanoparticles

In this paper, transparent conducting thin films based on both undoped and vanadium (V) doped zinc oxide Zn1−xVx O (x = 3, 5, 7 at.%), were studied. The thin films were prepared using a simple low cost deposition technique called spray pyrolysis (SP). The layers were deposited onto preheated glass substrates at 450 °C. The effect of vanadium on the microstructural, the morphological and the optical properties of ZnO material was carried out using X-ray diffractometer (XRD), micro Raman spectroscope, scanning electron microscope (SEM), energy dispersive analysis by X-ray (EDX) and UV-Vis-NIR spectrophotometer. We have demonstrated that doping with 3 at.% of V enhances the crystallinity of the films by estimating the grain size value, the dislocation density and the residual stress. Also, the SEM images have demonstrated that the vanadium concentrations do effect in the thin films morphology, from hexagonal-shaped grains to rounded crystals for higher doping concentrations. The optical analysis revealed that doping with 3 at.% of vanadium shows a remarkable enhancement in the average transmittance in the visible range 89% and in the band gap energy (3.3 eV). Moreover, the disorder inside the samples was estimated using Urbach equation. Therefore, the microstructural, the morphological and the optical results approve that doping with 3 at.% of V in ZnO lattices gives interesting results for the optical window material for solar cells application.

Synthesis and characterisation of polyaniline and/or MoO2/graphite composites from deep eutectic solvents via chemical polymerisation

Novel polyaniline (Pani) and/or graphite (Gr)/molybdenum dioxide (MoO2) composites have been successfully synthesised via an in situ chemical polymerisation method using a Deep Eutectic Solvent (DES) as the electrolyte. The chemical structure and properties of the Pani composites were characterised using various analytical techniques such as Raman, FTIR and UV–Vis spectroscopies, Thermo-Gravimetric Analysis (TGA), X-ray diffraction (XRD) and conductivity measurements, confirming its semi-crystalline nature. The results show shifts in the Raman, XRD and FTIR spectral features associated with the Pani composites, indicating that a matrix of metal oxide and/or graphite had formed in the polymer. Higher electrical conductivity was observed for the Pani/Gr (5.58 S cm−1) and Pani/Gr/MoO2 (9.87 S cm−1) composites compared to pure Pani (1.25 S cm−1). The homogenous growth of Pani chains on the graphite and MoO2 network were clearly observed by Scanning Electron Microscopy (SEM) and Energy Dispersive Analysis by X-ray (EDAX). A larger surface area and greater porosity were achieved in the Pani/MoO2, Pani/Gr/MoO2 and Pani/Gr samples, while a more compact structure was obtained for the Pani sample. These findings support that the idea that the polymer/graphite composites would be more useful for electrochemical charge transport, supercapacitance and energy storage applications compared to those using the pure polymer alone.

Electrochemical performances of LiNi1−xMnxPO4 (x = 0.05–0.2) olivine cathode materials for high voltage rechargeable lithium ion batteries

This study demonstrated to synthesis of carbon-free lithium nickel phosphate (LiNiPO4) and its analogue of manganese doped LiNi1−xMnxPO4 (x = 0.05–0.2) cathode materials by a facile polyol method and their suitability for use in high voltage lithium ion batteries (LIBs). The physicochemical properties were analyzed using X-ray diffraction, Fourier transform infra-red, Raman, field emission scanning electron microscopy (FE-SEM), energy dispersive analysis by X-ray (EDX), and electrochemical studies. FE-SEM showed that the spherical shape particles were uniformly distributed on the surface and EDX confirmed the presence of all the elements in the LiNi1−xMnxPO4 nanostructure. Substitution of Mn dopants with LiNiPO4 significantly improved the electrical and electrochemical performances for LiNi1−xMnxPO4 (x = 0.05–0.2) cathodes. The highly conducting LiNi1−xMnxPO4 (x = 0.1) cathode exhibited initial discharge capacity of 94.2 mA h g−1 at C/4 rate, and 62% capacity retention after 100 cycles between 2.8 and 5.6 V. These features promote LiNi1−xMnxPO4 as a suitable cathode material for high voltage LIBs.