EDX Elemental Analysis Research Articles

A potential trackable bone filler: Preparation and characterization

AbstractThis study reported the synthesis of fluorescent hydroxyapatite/alginate/carbon quantum dots (HA/Alg/CQDs) nanocomposites via the co‐precipitation technique. The N‐doped CQDs as a new class of fluorescent materials were prepared by the citric acid pyrolysis method, with an average size around 4 nm. Physical, chemical, and optical properties of the synthesized nanocomposites were investigated by X‐ray diffraction (XRD), Fourier‐transformed infrared spectroscopy (FTIR), atomic force microscopy (AFM), field‐emission scanning electron microscopy (FESEM), UV–visible spectroscopy, and photoluminescence (PL) spectroscopy, respectively. The PL spectroscopy data verified the favorable in vitro luminescent emission of the HA/Alg/CQDs nanocomposites in comparison with HA/Alg and HA samples. The XRD patterns of the prepared samples confirmed the formation of crystalline HA in all composites, possessing a Ca/P ratio around 1.5 as obtained by EDX elemental analysis. The FESEM analysis exhibited HA nanoplates that homogeneously distributed throughout the alginate matrix. Therefore, the synthesized nanocomposites could be regarded as potential trackable drug carriers for hard tissue engineering applications.

High temperature solid particle erosion comparison of atmospheric plasma sprayed MCrAlY coatings

Two different protective MCrAlY (NiCrAlY and NiCoCrAlY) coatings were obtained using the Atmospheric Plasma Spray (APS) method on the Inconel 718 substrate. It is aimed to inspect the rate of erosion and increase working life in last stage components of gas turbines, turbine blades and vanes. Because of the nature of exhaust, they are exposed the high temperature solid particle erosion. The High Temperature Solid Particle Erosion (HTSPE) test rig, which was specially designed and manufactured in accordance with the internationally accepted standard of ASTM G211–14, was used in the experiments. The experiments were conducted with three different air temperatures (room temperature, 300 °C and 600 °C), three different erosive particle impact angles (30°, 60° and 90°), constant particle impact velocity (∼97 m s−1) and particle size (400 μm Al2O3). SEM images, XRD analysis, EDX mapping and EDX element analysis were used to characterize the coatings. The erosion resistance results were interpreted with respect to the porosity values, hardness and surface roughness measurements of the coatings in details. As a result of the experiments, MCrAlY coatings showed ductile material behaviour compatible with erosion wear, and the cobalt element added to the coating structure contributed positively to increasing erosion resistance.

Benchmarking of oxygen evolution catalysts on porous nickel supports

Summary Active and inexpensive oxygen evolution reaction (OER) electrocatalysts are needed for energy-efficient electrolysis applications. Objective comparison between OER catalysts has been blurred by the use of different supports and methods to evaluate performance. Here, we selected nine highly active transition-metal-based catalysts and described their synthesis, using a porous nickel foam and a new Ni-based dendritic material as the supports. We designed a standardized protocol to characterize and compare the catalysts in terms of structure, activity, density of active sites, and stability. NiFeSe- and CoFeSe-derived oxides showed the highest activities on our dendritic support, with low overpotentials of η100 ≈ 247 mV at 100 mA cm–2 in 1 M KOH. Stability evaluation showed no surface leaching for 8 h of electrolysis. This work highlights the most active anode materials and provides an easy way to increase the geometric current density of a catalyst by tuning the porosity of its support.

Protective Role of Copper Oxide-Streptomycin Nano-drug Against Potato Brown Rot Disease Caused by Ralstonia solanacearum

Potato plants can be infected by different bacterial diseases, among them, the potato brown rot disease, caused by Ralstonia solanacearum. The novelty of the present research is to assess the potential impact of the synthesized copper oxide NPs (CuO NPs)-streptomycin nano-drug synthesized by gamma irradiation for inducing the systemic resistance against potato brown rot disease. CuO NPs-streptomycin was completely-characterized by UV–Vis., XRD, FTIR, HRTEM, SEM, and EDX elemental analysis. In the greenhouse experiment, the efficiency of CuO NPs was tested after three times of application. Disease index percent, phytochemicals, and metabolic indicators of resistance (as a response to induction of systemic resistance) were investigated. Our results indicated that treatment with CuO NPs during planting was more effective for increasing the protection percent by 55.8% and reducing the disease severity by 37.5% in the infected potato plants. CuO NPs-streptomycin increased not only the photosynthetic pigments but also the osmolytes contents. The highest reduction in malondialdehyde (44.89%) and hydrogen peroxide (32.9%) contents was achieved in the case of potato plants treated one week after planting. Therefore, it suggested applying CuO NPs-streptomycin in controlling plant disease since they are cost-effective and eco-friendly.

Microfibers nanocomposite based on polyacrylonitrile fibers/bismuth oxide nanoparticles as X‐ray shielding material

AbstractThe main focus of the current study was to fabricate fibrous nanocomposite based on polyacrylonitrile (PAN) fibers containing Bi2O3 NPs as the X‐ray shielding material. Bi2O3 NPs were synthesized based on the solid dispersion evaporation method and dispersed into PAN polymer solution with different weight concentrations. The electrospinning technique was used to fabricate nanocomposite. The morphology, surface functional group, wettability, elemental analysis, and X‐ray shielding efficacy of the fabricated nanocomposite were thoroughly evaluated. The dimeter of the fibrous nanocomposites containing 10, 20, and 30 wt% Bi2O3 NPs were 1.33 ± 0.08, 1.01 ± 0.11, and 1.69 ± 0.32 μm, respectively. EDX elemental analysis showed that NPs were uniformly distributed into/onto the fibers. The X‐ray shielding studies showed that the prepared nanocomposites effectively attenuate the intensity of the X‐ray. The entrance surface dose for the negative control was 24.10 ± 1.71 mSv and the application of the nanocomposites significantly reduced the entrance surface dose. The results showed NPs concentration‐dependent CT number shift as the indication of X‐ray protection and the highest value was obtained by 30 wt% NPs. The obtained results implied that the fabricated nanocomposites effectively attenuate the radiation and they could be applied as the X‐ray shielding materials.

Каталитические свойства продуктов гидролиза бромида иттрия

The effect of hydrolysis time, final pH of synthesis, and hydrothermal treatment on the for-mation of yttrium oxyhydroxides obtained by alkaline hydrolysis of yttrium bromide was studied. Hydrolysis was carried out at different duration of the hydrolytic agent addition: 5 minutes, 1 hours and 24 hours, as well as at different final pH values were checked: 8, 9 and 10. Methods for characterization of resulting materials were: thermogravimetry combined with differential scanning calorimetry and mass spectrometry of gaseous products of thermolysis, X-ray diffraction, high-resolution scanning electron microscopy with EDX elemental analysis. In addition, a photocatalytic activity of the obtained samples was evaluated in the decomposition reaction of methylene blue under the UV radiation. It is established that the hydrolysis of yttrium bromide involves the capture of a significant amount of impurities of bromide and carbonate ions, which are present in the structure of the samples. The physical and chemical characteristics of yttrium bromide hydrolysis products depend on both the pH value and hydrolysis duration, as well as on hydrothermal treatment. The latter significantly increases the crystallinity of the samples and their photocatalytic performance in destruction reaction of methylene blue.

Investigation on the site preferences & magnetic properties of Co-doped SrAl4Fe8O19 hexaferrite

The present work describes the structural and magnetic properties of partially Co substituted SrAl4CoxFe8-xO19 (0.0≤ x ≤ 0.6) ferrites. Single-phase strontium hexaferrite (p63/mmc) was synthesized by the sol-gel auto combustion method. The structural studies were carried out by the Rietveld analysis to get the information about the substituted sites of transition metal ions, bond length, and bond angle. Types of the bond were also explored through FTIR. EDX elemental analysis and mapping had also verified the presence of single-phase strontium hexaferrite. The effect of Co ion substitution on the magnetic properties was investigated with the help of a magnetic property measurement system (MPMS). The relationship between the occupancy of transition metal ions over the five sub-lattice sites was analyzed. The magneto-crystalline anisotropy was analyzed from the “Law of Approach to Saturation magnetization (Ms)” method. The oxidation state of the Co ion was also examined by the XAS spectra. The substitution of Co+3 enhanced the magnetization and permeability of the ferrites. Results indicated the significant dependency of Co+3 ion on the magnetic properties of strontium hexaferrite.

Fabrication of Alumina-Doped Optical Fiber Preforms by an MCVD-Metal Chelate Doping Method

This paper reports on the fabrication of alumina-doped preforms using a modified chemical vapor deposition (MCVD)-vapor phase chelate delivery system with Al(acac)3 as the precursor. The objectives of this work are to study the deposition process, the efficiency of the fabrication process, and the quality of the fabricated fiber preforms. Two parameters are studied, the Al(acac)3 sublimator temperature (TAl °C) and the deposition direction (i.e., downstream and upstream). Other parameters such as the oxygen flow and deposition temperature are fixed. The results show that high uniformity of the refractive index difference (%RSD < 2%) and core size (%RSD < 2.4%) was obtained along the preform length using downstream deposition, while for the combined upstream and downstream deposition, the uniformity deteriorated. The process efficiency was found to be about 21% for TAl °C of 185 °C and downstream deposition. From the EDX elemental analysis, the refractive index was found to increase by 0.0025 per mole percent of alumina.

Application of ascorbic acid in the synthesis of rGO/micro-octahedral Cu2O nanocomposites and its effect on the wide linear response range of glucose detection

In this study, a simple and scalable method with the application of Ascorbic acid has been reported for the fabrication of decorated reduced graphene oxide by Cu2O micro-octahedrons (rGO/ micro-octahedral Cu2O nanocomposites) for non-enzymatic glucose sensor using differential pulse voltammetry (DPV) techniques. The structural study of rGO/ micro-octahedral Cu2O using detailed XRD analyses, Raman spectroscopy, FESEM imaging, EDX elemental mapping and BET-BJH analyses revealed that the application of ascorbic acid in the synthesis process enhances the morphology, surface area, charge transfer and electrocatalyst properties of the nanocomposite. XPS analysis revealed the significant reduction of GO with the distinct peak of C–C in the C 1 s orbital scan. Quenching of satellite peaks (Cu2+) in Cu 2p orbital scan accompanied by the appearance of Cu-C new bond were indications of CuO phase elimination and hybridization of rGO/Cu2O structure. The modified electrodes with Nafion showed a wide linear span of 1 µM- 9 mM for glucose detection, high sensitivity of 415 µA mM−1 cm−2 with low detection limit of 0.96 µM and significantly being selective among different species. The sensitivity measurement without Nafion as a Nafion-free modified electrode was still high as 24.8 µA mM−1 cm−2 with the same wide linearity range and low detection limit of 0.53 µM. The stability of 97.95% in signal change after 56 days and repeatability of the modified electrode with relative standard deviation of 4.06% were also obtained. The modified GC/rGO/micro-octahedral Cu2O electrode revealed its electrocatalytic activity toward glucose oxidation that was excellently competitive with HPLC measurement of glucose in human serum.

Hydrothermal Synthesis of Polyoxometalate Containing Cobalt Ion, and Its Polyurethane Composites for Dielectric Material Applications

ABSTRACT Polyurethane (PU) composites were prepared with different diisocyanate and diol compounds by adding cobalt ion-based polyoxometalate (Co-POM) as reinforcement. For the determination of using potential in microelectronic applications, the dielectric behavior and dielectric constant of these PU composites were investigated and compared to pure polyurethane structures. For this aim, firstly, Co-POM with Keggin structure was obtained from ammonium heptamolybdate, 1,10-phenanthroline ligand and a cobalt (II) salt by hydrothermal synthesis technique. Then, polyurethane/Co-POM composites (PU/Co-POM) were prepared with ethylene glycol, nonaromatic diisocyanate and different amounts of Co-POM reinforcement (1%, 3%, 5% and 10%, w/w) by in situ polymerization and mix-blend technique. Obtained PU/Co-POM composites were characterized in detail by infrared spectroscopy, Elemental Mapping, Energy-dispersive X-ray spectroscopy (EDX) and X-ray powder diffraction (XRD) spectroscopy. The surface structure, morphology and roughness of PU/Co-POM composites were investigated by SEM and AFM analysis. The elemental maps of the PU/Co-POM surface were examined by EDX elemental mapping analysis methods. Thermal stability, Tg values and thermal decomposition temperatures of PU/Co-POM structures were determined by different thermal analysis techniques. Thermal analysis results showed that the PU/Co-POM composites are thermally stable up to approximately 200°C and Tg values of synthesized PU composites are seen between 54.72°C and 75.15°C. The dielectric properties and dielectric constants of the PU/Co-POM composites were determined in the frequency range 1 Hz to 1000 kHz at room temperature using impedance analyzer. Dielectric constants of these composites were ranged from 5.50 to 9.26 according to their polarizability and H-bonding ability of PU matrix structure. According to the dielectric measurements, the dielectric constants of the PU/Co-POM structures were significantly decreased compared to the pure PU structures.

Pd@Al-containing mesoporous silica Yolk–Shell-structured nanospheres as high performance nanoreactors for the selective hydrogenolysis of glucose to 1,2-propylene glycol

In this work, a series of Pd@Al-MSiO2 yolk–shell-structured nanospheres (YSNSs) with different Al contents were synthesized by a facile one-pot method. The EDX elemental analysis and high-magnification TEM image of Pd@Al-MSiO2 YSNSs confirmed that its well-defined yolk-shell structure with a moving Pd core and mesoporous silica shell rich in Al species. Furthermore, Solid state NMR and Py-FTIR results confirmed that Al species grafting mainly formed 4-coordinated Al (AlO4) in the mesoporous silica framework which led to generating abundant Lewis acid sites. The influence of Al species on the physicochemical properties of Pd@Al-MSiO2 YSNSs, as well as their catalytic performance for the hydrogenolysis of glucose to 1,2-propylene glycol (1,2-PG), was investigated. The mesoporous silica shell with abundant Lewis acid sites is a significant contributor to the isomerization of glucose into fructose, while the Pd core plays a role in promoting the hydrogenation of intermediates. The unique hollow space inside the Pd@Al-MSiO2 YSNSs provides a location for the retro-aldol condensation of fructose and consequently avoids direct hydrogenation of fructose. The as-synthesized Pd@Al3-MSiO2 YSNSs shows superior catalytic activity (1,2-PG selectivity of 47.4%, glucose conversion of 95.4%) in the hydrogenolysis of glucose, and far outperforms the Pd/Al3-MSiO2 catalysts. In addition, owing to the influence of the 4-coordinated Al species on the geometry and chemical properties of the mesoporous silica shell, the nanospheres show good stability and reusability over multiple catalytic cycles without significant loss of activity.

Nanowire crystals of tantalum nitride grown in ammonium halide fluxes at high pressures

Nanowire crystals of a tantalum nitride phase have been grown from epsilon-tantalum nitride and ammonium halide precursors at high pressures exceeding several gigapascals. Synchrotron x-ray diffraction and Transmission Electron Microscopy (TEM) observations revealed that they had crystallized in an unreported hexagonal structure with lattice parameters of a = 3.050(1) Å and c = 2.909(2) Å. The one-dimensional growth orientation was along the crystallographic [001] direction. Scanning TEM–EDX elemental analyses showed that the nanowire crystals were composed of tantalum and nitrogen with small amounts of oxygen. The presence of the melted ammonium halides combined with supercritical ammonia acting as a reactive flux at high pressure and temperature played a significant role in the nanowire crystal growth. Raman spectroscopy performed on several single crystal nanowires pointed toward metallic properties, and the temperature dependence of the magnetization measured by Superconducting Quantum Interference Device magnetometry suggested a superconducting transition about 6.2 K. The analysis of the compression behavior revealed an incompressible nature, and the bulk modulus was determined to be 363(6) GPa.

3:27 PM Abstract No. 25 Iodinated coating of decayed Y-90 microspheres to improve radiopacity with cone-beam computed tomography

To envelope SIR-Spheres (SS) with a chitosan/iodine shell in order to display greater contrast enhancement compared to non-coated control SS with cone-beam CT. Centrifuge 1000μL of radioactively inactive SS at 10,000 RPM for 10 minutes and remove excess water. Combine 7mL of Omnipaque (Op) solution (2% acetic acid, 3 mg/mL chitosan) with the pelleted SS and place on a shaker plate for 30 minutes. While shaking, add 7mL of 10 mg/mL TPP (in 100% Op) dropwise over 1 minute, and continue to shake for 30 minutes. Wash the sample by centrifuging at 14,000 RPM for 10 min then resuspending in diH2O. Continue these spin/wash cycles for a total of 3 washes. Remove 25μL of sample and place on a scanning electron microscope (SEM) stub for SEM and Elemental Dispersive X-Ray Spectroscopy (EDX) analysis. Transfer the remaining washed sample to a 1.5mL centrifuge tube for cone-beam CT assessment. In order to add additional coatings, the above steps were repeated. Cone beam CT imaging showed an increase in contrast resolution of double and triple coated SS when compared to control SS. Better contrast resolution was seen with triple coated SS when compared to double coated SS. SEM images of control SS, singe coated SS, double coated SS, and triple coated SS showed progressive layering of chitosan/Op coatings with each additional coating attempt. EDX elemental analysis results show a stepwise increase in iodine content when looking at control SS, single coated SS, double coated SS, and triple coated SS, with average iodine contents of 0%, 33.4%, 42.8%, and 63.0% respectively. The ability to intraoperatively assess SIRT dosage delivery would allow localization of treated and untreated regions. With this knowledge, other interventions can be applied to ensure a more efficacious treatment plan. In this study we were able to apply significant amounts of radiopaque iodine to the surface of SS. With the utilization of SEM, EDX, and cone-beam CT, we confirmed that we (1) successfully enveloped SS in crosslinked chitosan, (2) successfully entrapped iodinated molecules within this chitosan shell, and (3) successfully demonstrated visibility with cone-beam CT of SS with the iodinated shell.

Iron and silicon oxide doped/PAN-based carbon nanofibers as free-standing anode material for Li-ion batteries

The advanced rechargeable batteries have been upgraded by the production of free-standing electrodes through electrospinning technology. This study aimed to introduce a novel hybrid composition to design a free-standing carbon nanofiber (CNF) based anode by the addition of iron acetylacetonate Fe(AcAc)3 as active material and TEOS(tetraethoxysilane)/APTES(aminopropyl triethoxysilane) as an additive for Li-ion batteries. Polyacrylonitrile(PAN) was used as the polymer matrix in the spin dope, and the inclusion of Fe(AcAc)3 and TEOS/APTES resulted in compositional change, producing iron oxide and silica nanoparticles throughout the matrix. Different oxidation states and the presence of embedded iron oxide nanoparticles in CNF were identified by XPS and EDX elemental mapping analysis. PAN-TEOS-APTES-Fe(AcAc)3 based anode material was capable of enhancing the reversible specific capacity as much as 732 mAhg−1 at 500 mAg−1 lasting for 300 cycles, along with the rate capability as high as 815 mAhg−1 at 200 mAg−1. Furthermore, EIS analysis and EX-situ FESEM showed decreased impedance after cycling with the stable morphology of PAN-TEOS-APTES-Fe(AcAc)3 CNF-film. Conclusively, non-woven, binder-free, current collector free, free-standing CNF anode film doped with iron-oxide and silica nanoparticles was indeed a novel approach for Li-ion batteries and can be considered for other batteries particularly for Li-S batteries.

Antibacterial and Antibiofilm Potential of Mono-dispersed Stable Copper Oxide Nanoparticles-Streptomycin Nano-drug: Implications for Some Potato Plant Bacterial Pathogen Treatment

The novelty of this work is to estimate the antibacterial and antibiofilm capabilities of the mono-dispersed copper oxide nanoparticles (CuO NPs)-streptomycin nano-drug which synthesized by a cost-effective and eco-friendly gamma irradiation method. The incorporated CuO NPs-streptomycin was fully defined by UV–Vis., XRD, FTIR, HRTEM, DLS, HRSEM and EDX elemental analysis. In vitro antibacterial and antibiofilm activities of CuO NPs-streptomycin were examined towards pathogenic bacteria-causing brown, ring, soft rot and black leg diseases in potato plant. The proposed reaction mechanism regarding the synergistic potential between CuO NPs and streptomycin was estimated. The incorporated CuO NPs-streptomycin displayed an absorption peak at 585.0 nm specific for the Surface Plasmon Resonance. Results achieved from HRTEM, HRSEM and XRD verified the mono-dispersed crystalline character of the fabricated CuO NPs-streptomycin with a common particle size of 20.20 nm. CuO NPs-streptomycin exhibited an encouraging antibacterial activity against Clavibacter michiganensis subsp. sepedonicus (35.50 mm ZOI). Additionally, CuO NPs-streptomycin displayed enhanced biofilm inhibition percentage of about 90.99%, 84.23%, and 83.42% toward C. michiganensis subsp. sepedonicus, Ralstonia solanacearum, and Dickeya solani, respectively. Consequently, according to the prominent characteristics, this research could provide insights for determining dangerous agricultural challenges, potato packaging and processing and new nano-drug formula for invading potato pathogenic bacteria through the cultivation.

Reparative Dentin Formation Using Stem Cell Therapy versus Calcium Hydroxide in Direct Pulp Capping: An Animal Study.

Direct pulp capping process is a therapeutic method aimed at maintenance of pulp vitality and health by using a biocompatible material placed directly over the exposed pulp. The aim of this study was to evaluate and compare the effect of direct pulp capping procedures by dental pulp stem cells (DPSCs) or calcium hydroxide on dentin tissue formation. Three mongrel dogs were used as experimental model. Two access cavities were prepared in the right and left mandibular fourth premolars in all dogs to expose and extirpate the pulp tissues which were processed in the lab to obtain a single-cell suspensions. The isolated cells were cultures in odontogenic medium for subsequent differentiation. The maxillary teeth (3 incisors and one canine) of the corresponding dog number were subjected to class V cavities to expose their pulps which were assigned into 2 groups of 12 teeth each ( group I - pulp capping with calcium hydroxide) and (group II - pulp capping with dental stem cells DPSCs). The operated teeth were collected after 3 months and processed for histological and electron microscopic examinations. Specimens were subjected to elemental analysis of calcium and phosphorus. EDX elemental analysis revealed significant differences in the calcium and phosphorous wt, % in the reparative dentin of calcium hydroxide treated group which confirmed histologically. Direct pulp capping by DPSCs has shown promising generative potential for regaining normal dentin.

Fabrication of Ultra-Pure Anisotropic Zinc Oxide Nanoparticles via Simple and Cost-Effective Route: Implications for UTI and EAC Medications.

The purposes of this work are to evaluate the antimicrobial, antibiofilm, anticancer, and antioxidant abilities of anisotropic zinc oxide nanoparticles (ZnO NPs) synthesized by a cost-effective and eco-friendly sol-gel method. The synthesized ZnO NPs were entirely characterized by UV-Vis, XRD, FTIR, HRTEM, zeta potential, SEM mapping, BET surface analyzer, and EDX elemental analysis. Antimicrobial and antibiofilm activities of ZnO NPs were investigated against multidrug-resistant (MDR) bacteria and yeast causing serious diseases like urinary tract infection (UTI). The anticancer activity was performed against Ehrlich ascites carcinoma (EAC). Additionally, antioxidant scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) was observed. The synthesized ZnO NPs exhibited an absorption peak at 385.0nm characteristic to the surface plasmon resonance (SPR). Data obtained from HRTEM, SEM, and XRD confirmed the anisotropic crystalline nature of the prepared ZnO NPs with an average particle size of 68.2nm. The calculated surface area of the prepared ZnO NPs was 10.62m2/g and the porosity was 13.16%, while pore volume was calculated to be 0.013cm3/g and the average pore size was about 3.10nm. The prepared ZnO NPs showed promising antimicrobial activity against all tested UTI-causing pathogens. It showed a prominent antimicrobial capability against Candida tropicalis with a zone of inhibition (ZOI) reaching 22.4mm, 13mm ZOI for Bacillus subtilis, and 12.5mm ZOI for Pseudomonas aeruginosa. Additionally, the prepared ZnO NPs showed enhanced biofilm repression of about 79.33%, 72.94%, and 33.68% against B. subtilis, C. tropicalis, and P. aeruginosa, respectively. Moreover, the prepared ZnO NPs had a powerful antioxidant property with 33.0% scavenging ability after applied DPPH assay. Surprisingly, upon ZnO NPs treatment, cancer cell viability reduced from 100 to 58.5% after only 24h due to their unique antitumor activity. Therefore, according to these outstanding properties, this study could give insights for solving serious industrial, pharmaceutical, and medical challenges, particularly in the EAC and UTI medications.

Growth dynamics of CBD-assisted CuS nanostructured thin-film: optical, dielectric and novel switchable device applications

The microcrystal structure of copper sulfide (CuS) nano-structured ultra-thin film was prepared on glass substrate from aqueous ammonia solution and sodium hydroxide at 60 °C using a simple and cost-effective chemical bath deposition (CBD). The powder X-ray diffraction method was used to characterize the hexagonal structure of the prepared CuS thin-film. While, surface morphology and surface topology were investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The optical properties were investigated by using UV–visible absorption spectrum. The electronic properties including average energy gap (Penn gap), Fermi energy, electronic polarizability and valence electron plasma energy of CuS thin films were determined. Semiconductor characterization of CuS film was confirmed using temperature dependent conductivity analysis. To prove the positive photoconductivity of nano-structured CuS nano-structured thin film, photoconductivity measurements were performed. I–V characteristics result, and Hall Effect measurements were also evaluated. Our results showed that the prepared CuS nano-structured thin films have higher crystallinity, purity and higher content of copper (Cu: 89.6%) as confirmed by XRD and EDX elemental analysis, respectively. While, their optical band gap energy is about 2.2 eV. Polarization-dependent Raman investigations allowed sample identification by dominant peaks at 265 cm−1 and 474 cm−1, proving the formation of CuS. Moreover, stimulating energy was found to be 0.028 eV by employing DC conductivity measurements. The estimated surface roughness was about (115 nm) with an average thickness of about (16.3 nm) as obtained from AFM analysis. Finally, remarkable smooth multi-colored marble like textural patterns have been recorded confirming the novel switching as recorded by the polarizing optical microscopy.

Metal Ion Sensing and Electrochemical Behavior of MOF Derived ZnCo2O4

A metal‐organic framework (MOF) with the formula {(H2pip)[Zn1/3Co2/3(pydc‐2,5)2(H2O)]·2H2O}{where H2pip = piperazinediium, pydc‐2,5 = pyridine‐2,5‐dicarboxylate}, 1, has been synthesized. To confirm the structure and phase purity of 1, the PXRD pattern of the synthesized compound has been compared with the simulated PXRD pattern generated from the single‐crystal X‐ray data of isomorphous pure Co compound synthesized by Niu and Co‐workers. Upon solid state annealing of the mixed‐metal precursor (MOF) at 400 °C for one hour, pure ZnCo2O4 was obtained. The phase purity of ZnCo2O4 was confirmed by powder X‐ray diffraction. The as obtained ZnCo2O4 was fully characterized using PXRD, SEM, TEM, and EDX elemental mapping analysis. The particle size is in the range of 22 nm‐40 nm with a dominant size of 30 nm. The emissive properties of nano‐sized ZnCo2O4 at 391 nm upon excitation at 310 nm have been probed for the luminescence‐based sensing of metal cations in aqueous medium. The metal ion sensing is based on the differential change in intensity, which in turn reflects the strength of the interaction between ZnCo2O4 and the metal ion. Such interactions can be rationalized within the framework of the ligand exchange rate as well as ionic radii of the aquated metal ions. Accordingly, Cu2+ and Hg2+ with highest ligand exchange rate exhibit maximum luminescence quenching, 71.7 % and 51 %, respectively. On the other hand, the nanostructured ZnCo2O4 also shows super capacitance behavior with a maximum energy density of 2.39 Wh kg–1 at a power density of 36.66 W kg–1.

Interfacial Design of Metallic 1T-MoS2/Carbon Nanotubes for High-Electrocatalytic Hydrogen Evolution Performance

The development of effective non-noble metal based electrocatalysts for the electrocatalytic hydrogen evolution reaction (HER) at lower overpotentials has attracted tremendous attention due to its important role for various electrochemical energy storage devices.1,2 In this study, a simple hydrothermal approach is implied for the preparation of metallic 1T-MoS2/carbon nanotubes (1T-MoS2/CNTs), which acts as an efficient electrocatalyst for HER.3 Fig. 1a, b, and c show the TEM images of 1T-MoS2/CNT composite, in that the 1T-MoS2 consists of a few-layered nanometers in structure and the CNT are well distributed homogenously in the 1T-MoS2 nanosheets, which can reduce aggregation and restacking of the 1T-MoS2 nanosheets. In addition, it can be seen from the fig. 4d that the presence of more intrinsic defects in the 1T-MoS2 nanosheets (marked as circles) was observed, which might result in an expansion of the interlayer spacing. Moreover, the HRTEM image (Fig. 1d) confirmed the presence of the octahedral 1T phase (marked as square) in 1T-MoS2/CNT composite. Besides, 1T-MoS2/CNT composite has been characterized by EDX elemental mapping analysis (Fig. 1f), which shows the existence and homogeneous distribution of Mo, S, and C elements.The tuning of catalytically more active sites and enhancement in the electron transport property can be achieved by designing of the defect-rich 1T-MoS2/CNTs composite material. The unique interfacial composition of the defect-rich 1T-MoS2/CNTs enables enhanced electrocatalytic HER performance with a low onset potential of 96 mV, a small Tafel slope of 54 mV dec-1 and low overpotential of 172 mV at a current density of 10 mA cm−2 (Fig. 1g). In addition, the 1T-MoS2/CNTs demonstrate superior long-term stability in acid conditions and the developed approach is easily applied to the large-scale production of efficient electrocatalysts. The electrocatalytic performance of 1T-MoS2/CNTs composite is also compared with the 1T-MoS2, CNTs, 2H-MoS2 modified electrodes and the commercial Pt/C catalyst. This high-electrocatalytic HER performance is likely attributed to the synergistic effects between the MoS2 nanosheets and CNTS, and rich defects.4 Moreover, DFT calculations also have proved that 1T-MoS2/CNTs show higher free energy change for hydrogen adsorption (ΔGH) than the 1T-MoS2 and CNTs. This work provides a novel and simple strategy to design 1T-MoS2/CNTs for high-performance applications in energy storage fields.