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The prepared NVOY electrode achieves high stability and excellent cycle performance for AZIBs by embedding polypyrrole in ammonium vanadate layers to remove excess ammonium ions, expand the interlayer spacing, and enhance electronic conductivity. [Display omitted] Ammonium vanadate with stable bi-layered structure and superior mass-specific capacity have emerged as competitive cathode materials for aqueous rechargeable zinc-ion batteries (AZIBs). Nevertheless, fragile N H...O bonds and too strong electrostatic interaction by virtue of excessive NH 4 + will lead to sluggish Zn2+ ion mobility, further largely affects the electro-chemical performance of ammonium vanadate in AZIBs. The present work incorporates polypyrrole (PPy) to partially replace NH 4 + in NH 4 V 4 O 10 (NVO), resulting in the significantly enlarged interlayers (from 10.1 to 11.9 Å), remarkable electronic conductivity, increased oxygen vacancies and reinforced layered structure. The partial removal of NH 4 + will alleviate the irreversible deammoniation to protect the laminate structures from collapse during ion insertion/extraction. The expanded interlayer spacing and the increased oxygen vacancies by the virtue of the introduction of polypyrrole improve the ionic diffusion, enabling exceptional rate performance of NH 4 V 4 O 10. As expected, the resulting polypyrrole intercalated ammonium vanadate (NVOY) presents a superior discharge capacity of 431.9 mAh g−1 at 0.5 A g−1 and remarkable cycling stability of 219.1 mAh g−1 at 20 A g−1 with 78 % capacity retention after 1500 cycles. The in-situ electrochemical impedance spectroscopy (EIS), in-situ X-ray diffraction (XRD), ex-situ X-ray photoelectron spectroscopy (XPS) and ex-situ high resolution transmission electron microscopy (HR-TEM) analysis investigate a highly reversible intercalation Zn-storage mechanism, and the enhanced the redox kinetics are related to the combined effect of interlayer regulation, high electronic conductivity and oxygen defect engineering by partial substitution NH 4 + of PPy incorporation. [ABSTRACT FROM AUTHOR]

Building up and an investigating the efficiency of the cost-effective modified graphite for hybrid supercapacitor application is fascinating due to an extraordinary performance of graphite in battery application in day-to-day life about past decades. The metal oxides (Fe, Co, Ni) embedded in graphite was synthesized through the facile ultrasonication-assisted technique. Fe–Co–Ni deposited on graphite (Fe–Co–Ni-G) was studied structurally and morphologically by fourier transform infrared spectroscopy, X-ray diffraction analysis, field emission scanning electron microscopy, and high resolution transmission electron microscopy analyses. The electrochemical studies such as cyclic voltammetry, Galvanostatic charge–discharge analysis, and electrochemical impedance spectroscopy (EIS) analysis were revealed the supercapacitor performance of Fe–Co–Ni-G composite. The superior calculated areal capacitance of Fe–Co–Ni-G was 1355 mF cm−2 at 2 mA cm−2 which was higher than single metal deposited graphite (Fe-G 490 mF cm−2 at 2 mA cm−2) composite. EIS study supported the higher diffusion process of Fe–Co–Ni-G directed to higher supercapacitor performance that is possible for day-to-day life applications. [ABSTRACT FROM AUTHOR]

Currently, surface reflection of incident sunrays over solar cells results in degradation of output performance of the solar cells. This can be sorted out using an antireflection coating. In this investigation, ARC materials such as Titanium dioxide (TiO 2), Aluminium oxide (Al 2 O 3) and blended TiO 2 – Al 2 O 3 were utilized over the mono-crystalline Si (m-Si) solar cells. The ARCs for m-Si solar cell was coated using RF sputtering method. The optical, structural, electrical, I–V characteristics and temperature behavior of solar cell samples with coating and bare cells were studied. The elemental analysis was carried out using X-ray diffraction (XRD) method. The morphological study was conducted using High Resolution Transmission Electron Microscopy (HR-TEM) and Atomic Force Microscope (AFM). The electrical resistivity was measured in dark at room temperature using four-point probe technique. Optical characteristics was determined using UV–visible spectroscopy. It was discovered that the TiO 2 – Al 2 O 3 blend coated cell (I3) shows great performance than the other coatings. I3 solar cell demonstrated high power conversion efficiency (PCE) of 19.42 % and 20.16 %, when exposed to direct sunlight and neodymium radiation in both open and controlled environments. The findings indicate that TiO 2 – Al 2 O 3 blends are a suitable material for ARC applications, since they effectively reduce the incident photons scattering. [ABSTRACT FROM AUTHOR]

NiMoS/TiMg and NiWS/TiMg nanocatalysts were synthesized, characterized by various techniques and tested in the hydrodesulphurization (HDS) of dibenzothiophene (DBT). TiMg mixed oxides containing 5, 10 or 15 wt% of MgO were prepared by sol–gel and then used as catalyst supports. A constant atomic ratio of Ni/(Ni + M) = 0.5 was kept for all the catalysts (M = Mo or W). The catalysts were first prepared by sequential-wet impregnation. Then, after an ex-situ sulfidation process, they were characterized by high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), and physisorption of N2 following the BET method. The presence of MgO in the NiMoS/TiMg and NiWS/TiMg catalysts resulted in an enhancement in the HDS activity of DBT. In addition, their HDS activities were higher than those observed in the NiMoS/Ti and NiWS/Ti catalysts. Furthermore, higher HDS activity was found for the NiMoS/TiMg compared with their NiWS/TiMg catalysts counterpart. [ABSTRACT FROM AUTHOR]

In this study, mixed phase (tetragonal and monoclinic) Zirconia nanoparticles (ZrO2 NPs) namely, ZS3, ZS7 and ZS10 were synthesized via hydrothermal method at different pH values of (3, 7, 10) respectively. A combination of Powder X-ray diffraction (PXRD), High Resolution Transmission Electron Microscopy (HRTEM), and Selected Area Electron Diffraction (SAED) characterization techniques confirmed the formation of mixed phase ZrO2 nanoparticles. The photocatalytic behavior of synthesized ZrO2 NPs was examined for the degradation of anionic Congo Red (CR) Dye under visible light irradiation. A systematic study of the efficiency of the prepared ZS3, ZS7 and ZS10 nanoparticles was compared and it was found that ZS7 outperformed the ZS3 and ZS10 materials, having removal efficiency of up to 98.9% with 0.1 g of the prepared ZS7 nanoparticles for 75 ppm of Congo Red (CR) dye. Furthermore, the surface area analysis revealed that among the prepared materials, ZS7 exhibited the highest surface area, thereby corroborating the finding of its superior catalytic efficiency. Under the optimized experimental conditions, the degradation of dye followed first-order kinetics. ZS7 showed the highest removal efficiency in just 60 min of contact time for all the CR dye concentrations ranging from 50 to 100 ppm, making it a superior catalyst for the efficient removal of the targeted Congo Red dye. [ABSTRACT FROM AUTHOR]

Rare earth complexes have gained attention in recent years for their remarkable luminescence properties, especially their long lifetimes, clear emission bands, and significant luminous quantum efficiency. In the ultraviolet area, the lanthanide ions exhibit relatively tiny absorption. The current investigation systematically portrays the tailoring of the micro-structural, opto-electonic and defect related features of the sol-gel derived pristine and rare earth element-samarium (Sm3+) substituted tin oxide (SnO 2) i.e., Sn 1- x Sm x O 2 (x = 0.0, 0.1, 0.2 & 0.3) nanoparticles (NPs). The structural, optical, electronic, morphological, photo-induced luminescence and defects related characteristics of the NPs were explored as a function of samarium (Sm3+) substitution level. In-depth analysis of the structure-property correlation of the Sn 1- x Sm x O 2 NPs is the goal of this study, focusing especially on the properties related to vacancy evolution and luminescence. The elemental mapping results revealed through energy dispersive X-ray spectroscopic (EDS) technique confirmed that the Sm-substitution is distributed uniformly throughout the NPs. The X-ray powder diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM) studies corroborate that the Sm3+ substitution in the SnO 2 matrix causes the decrease in crystallite size of the NPs and increase in the dislocation density. A monotonic increase in lattice strain has been observed using the Williamson – Hall (W – H) approach, which is in line with the NPs' increased dislocation density and decreased crystallite size with the Sm3+ substitution level. The presence of vacancy-type defects inside the NPs was demonstrated by positron annihilation lifetime (PAL) spectroscopic measurements, and a decrease in defects was noticed as the level of Sm3+ substitution increased. To explore the optical characteristics and the evolution of the energy band gap with Sm3+ substitution level, the optical absorption (OA) spectroscopic measurement was carried out. As the Sm-substitution level rises, the optical energy band gap of the substituted SnO 2 NPs widens relative to that of pure SnO 2 NPs. The existence of various absorbance bands corresponding to the atomic vibrations within the NPs were investigated by the Fourier-transform infrared (FT-IR) spectroscopic technique. The photo-induced fluorescence (FL) emission spectroscopic analysis evidenced that the defect density decreased as the Sm-substitution level increased, which is in accordance with the PAL spectroscopic studies. The FL spectra showed the two typical near band edge (NBE) and deep level emission (DLE) peaks of the NPs. The proportion of different defects and vacancies associated with the FL emission transitions are portrayed as Pie-chart diagrams. The tailored NPs can establish to be effective candidates for possible spintronic and optoelectronic applications including magneto-optical devices. [ABSTRACT FROM AUTHOR]

The controlled synthesis of two‐dimensional nanocrystals of graphene particles instead of amorphous carbon quantum dots is highly challenging and requires tremendous efforts to optimize the reaction conditions. It has been observed that as a significant bio‐compatible zero‐dimensional material, graphene quantum dots are considered as a novel material for opto‐electronics, energy, biological and environmental applications. However, very few are known about their utilization in photocatalytic degradation of pesticides, especially organochlorine pesticides which are resistant to removal by conventional wastewater treatment methods. In this work, graphene quantum dots were produced from rice husk at relatively low temperatures, resulting in an average particle size of 3.3 nm. The high resolution transmission electron microscopy clearly showed the formation of spherical quantum dots having lattice fringes and the selected area electron diffraction pattern showed the crystallinity of the graphene quantum dots. A study of photodegradation of three highly toxic organochlorine pesticides namely, dichlorodiphenyl trichloro ethane, cypermethrin and fenvalerate were carried out using as‐synthesized graphene quantum dots from rice husk. Interestingly, all these pesticides were found to be degraded around 60 % to 70 % under visible light conditions. It confirmed that synthesized graphene quantum dots from rice husk can act as prominent photocatalyst for the degradation of pesticides and other pollutants. [ABSTRACT FROM AUTHOR]

Exploring magnetic order in nonferromagnetic substances, such as CuO:ZnO, becomes especially attractive when introducing defect states through nonmagnetic ion doping. In this study, we delved into the impact of Yb doping on the structural, morphological, optical, and magnetic properties of CuO:ZnO. The Yb doped CuO:ZnO was prepared with different Yb concentrations (x = 0.00–20 %) via the temperature-assisted co-precipitation method. X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), UV–Vis spectroscopy, and vibrating sample magnetometer (VSM) were used to investigate the structural, morphological, optical, and magnetic properties of Yb doped CuO:ZnO nanocomposites. The incorporation of Yb in CuO:ZnO nanocomposites leads to a notable shift of the characteristic XRD peaks of CuO and ZnO to lower angles, accompanied by an increase in the lattice parameters. UV–visible absorption spectroscopy shows an overall decrease in the optical band gap energy of ZnO as the Yb defect level increases. FE-SEM studies revealed the transformation of spherical structures into agglomerated non-spherical structures upon the introduction of Yb ions into CuO:ZnO nanocomposites. According to XPS data, the predominant valences of Yb-doped CuO:ZnO nanocomposites are Zn2+, Cu2+, and Yb3+. One noteworthy observation from the XPS results is that, in comparison to the intensity of O L or O ad peaks, the intensity of O V (Oxygen vacancy) defect peak increases when the Yb impurity concentration increases. Magnetic measurements demonstrated a diamagnetic order in pure ZnO, which converts to a ferromagnetic order with the incorporation of Yb defect states. The ferromagnetic properties of the Yb-doped CuO:ZnO nanocomposite can be ascribed to the exchange interaction of Yb3+ ions with defect states (Oxygen Vacancy) in ZnO and CuO. [ABSTRACT FROM AUTHOR]

High entropy thermoelectric oxides offer a route towards highly efficient thermoelectric energy conversion as the materials frustrate parasitic phonon transport. Here, entropy-stabilised perovskite oxide thermoelectrics (Ca 0.33 Sr 0.33 Ba 0.33)(Ti 0.5−x Zr 0.5−x Nb x)O 3 (x = 0, 0.1, 0.2, 0.33) were prepared via solid-state reaction with sintering at 1673 K under a reducing atmosphere. The products contained two high entropy perovskite phases with homogeneous elemental distributions at the nanoscale. Through optimising the Nb content, the Seebeck coefficient was increased, yielding an enhanced power factor of 39.5 μW m−1 K−2 at 873 K. High resolution transmission electron microscopy revealed the presence of a large number of defects of different dimensionality, which enhanced phonon scattering. A glass-like, ultra-low thermal conductivity of 1.6 – 1.9 W m−1 K−1 was achieved from room temperature to 873 K, amongst the lowest reported values for perovskite oxides. This work highlights the design of high entropy oxide perovskites based on non-toxic components having both high Seebeck coefficients and ultra-low thermal conductivity. [ABSTRACT FROM AUTHOR]

Superconducting qubits have arisen as a leading technology platform for quantum computing, which is on the verge of revolutionizing the world's calculation capacities. Nonetheless, the fabrication of computationally reliable qubit circuits requires increasing the quantum coherence lifetimes, which are predominantly limited by the dissipations of two-level system defects present in the thin superconducting film and the adjacent dielectric regions. In this paper, we demonstrate the reduction of two-level system losses in three-dimensional superconducting radio frequency niobium resonators by atomic layer deposition of a 10 nm aluminum oxide Al2O3 thin films, followed by a high vacuum heat treatment at 650 °C for few hours. By probing the effect of several heat treatments on Al2O3-coated niobium samples by x-ray photoelectron spectroscopy plus scanning and conventional high resolution transmission electron microscopy coupled with electron energy loss spectroscopy and energy dispersive spectroscopy, we witness a dissolution of niobium native oxides and the modification of the Al2O3-Nb interface, which correlates with the enhancement of the quality factor at low fields of two 1.3 GHz niobium cavities coated with 10 nm of Al2O3. [ABSTRACT FROM AUTHOR]

The synthesis of undoped and copper doped ZnS nanoparticles (NPs) by a facile starch mediated microwave assisted hydrothermal route is reported in this work. Polycrystalline, cubic ZnS nanostructure of the samples were revealed by X-ray diffraction studies. High resolution transmission electron microscopy (HRTEM) analysis revealed the crystalline nature of NPs with size distribution in 2–7 nm range. Analysis of X-ray emission induced by particles of samples indicated presence of copper content in the sample. Cu doping showed a strong influence on the green emission properties of the ZnS NPs under UV light illumination. The band gap values determined from UV–Vis absorption studies were higher than that for bulk ZnS (3.68 eV), confirming quantum confinement effect. Further, starch capping and Cu doping confirmed by Fourier transform infra-red (FTIR) spectra. A strong PL emission around 507 nm observed due to carrier transition from conduction band of ZnS to Cu2+ t 2 level. The intensity of this peak reduced at high dopant concentration due to quenching. [ABSTRACT FROM AUTHOR]

This paper reports synthesis by wet chemical route for neodymium doped lanthanum arsenates nanoparticles with chemical formula NdxLa1−xAsO4 (x = 0.0, 0.05, 0.10 and 0.15) and its characterization. Powder X-ray diffraction (PXRD) confirms monoclinic structure of the prepared nanomaterials. Crystallite size decreases with increasing concentration of Nd3+ ions. PXRD results are further validated by Rietveld refinement with low values of goodness factor (χ2). Morphology has been investigated by high resolution transmission electron microscopy (HRTEM) equipped with selected area electron diffraction (SAED) which shows the crystalline nature of nanomaterials. Various functional groups present have been studied by FTIR spectroscopy. The optical band gap calculated using UV–Vis diffuse reflectance spectroscopy is found to decrease with increasing dopant concentration. The emission spectrum studied by applying photoluminescence (PL) spectroscopy. At 315 nm excitation, the NdxLa1−xAsO4 exhibits a bright red emission with emission peaks in the range of 610–630 nm. Chromaticity plot shows that chromaticity coordinates are located in the red region. The dielectric analysis carried out to study variation of dielectric constant with frequency over range of 1–25 kHz and temperature range of 20–200 °C. The conductivity measurements are carried out and activation energy has been calculated. The variation of electrical modulus with frequency has also been observed. [ABSTRACT FROM AUTHOR]

Biodiesel has recently emerged as a renewable and environmentally benign fuel substitute for fossil‐derived energy sources. The use of heterogeneous solid catalysts for the generation of biodiesel from biomass‐derived fats and oils is sustainable. Among various reported catalyst supports, metal–organic frameworks (MOFs) have been popular choices for enhancing catalytic activity for biodiesel synthesis because of several outstanding features including porosity, high surface area, adjustable structures, and uniform pore sizes. In this research, the authors synthesized a novel nanocomposite of MOF‐supported hydroxyapatite (UiO‐66@HAp) using a facile impregnation technique and the characterization of the as‐synthesized catalyst was performed by different spectroscopic methods including powder X‐ray diffraction (PXRD), Fourier transform infrared (FTIR), X‐ray photoelectron spectroscopy (XPS), field emission gun‐scanning electron microscope (FEG‐SEM), energy dispersive X‐ray spectroscopy (EDS), high resolution transmission electron microscopy (HR‐TEM), thermogravimetric analysis (TGA), and N2 adsorption–desorption techniques. After successful synthesis, the catalytic property of the prepared material was evaluated in the palm oil transesterification into biodiesel. Product formation was confirmed by the 1H nuclear magnetic resonance (NMR) spectroscopy, 13C NMR, FTIR, and gas chromatography–mass spectrometry (GC–MS) of the biodiesel. The influence of different reaction variables such as catalyst dosage, methanol/oil molar ratio, temperature of the reaction, and reaction time was also studied. The outcomes revealed that the maximum biodiesel yield (∼97%) was obtained when 6 wt% catalyst was used with a 6:1 ratio of methanol/oil at 70 °C for 1 h. It was also observed that, even after 5 cycles of reuse, the catalyst was capable of producing significant amounts of biodiesel (over 90%). The results suggest that the synthesized novel catalyst holds a promising future in the sustainable production of biodiesel. [ABSTRACT FROM AUTHOR]

Nano size Z n 2 − x C u x V 2 O 7 (x = 0 ∼ 2) ceramics, prepared through a single step modified combustion method has been sintered at a relatively lower temperature for the first time. The thermodynamics of phase transition of the as prepared samples with respect to temperature was studied using Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). The powder X-ray diffraction (XRD) analysis of the samples along with Rietveld refinement of the data confirmed that the compositions crystalized in monoclinic structure despite increasing x from 0 to 2. Raman spectroscopic analysis carried out in the powders also corroborated the XRD analysis. The High Resolution Transmission Electron Microscopy (HRTEM), shows that the annealed powders have a particle size of around 43 nm. A systematic study on the densification behaviour of the cylindrical pellets was conducted in the range 680 0 C - 780 0 C to obtain optimal density. The microstructural study of the pellets sintered to the optimum density was conducted using Scanning Electron Microscopy (SEM). The electrical properties of the polished samples were measured using an Impedance Analyzer in the range 100 Hz – 1 MHz at different temperatures from 50 °C to 500 °C. On varying x from 0 to 2, the dielectric constant of Zn 2 V 2 O 7 ceramic showed a gradual increase from 7.9 to 15.9 at 10 kHz at room temperature. The Zn 2 V 2 O 7 ceramics showed a conductivity range from 4.10 × 10 − 9 S cm − 1 to 4.56 × 10 − 7 S cm − 1 between 300 °C and 450 °C.The present study confirmed the suitability of the ceramics as potential substrate material for LTCC applications. [ABSTRACT FROM AUTHOR]

Hydrogen energy possesses immense potential in developing a green renewable energy system. However, a significant problem still exists in improving the photocatalytic H 2 production activity of metal-free graphitic carbon nitride (g-C 3 N 4) based photocatalysts. Here is a novel Cu 3 P/CdS/g-C 3 N 4 ternary nanocomposite for increasing photocatalytic H 2 evolution activity. In this study, systematic characterizations have been carried out using techniques like X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM), Raman spectra, UV–Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), surface area analysis (BET), electrochemical impedance (EIS), and transient photocurrent response measurements. Surprisingly, the improved 3CP/Cd-6.25CN photocatalyst displays a high H 2 evolution rate of 125721 μmol h−1 g−1. The value obtained exceeds pristine g-C 3 N 4 and Cu 3 P/CdS by 339.8 and 7.6 times, respectively. This could be the maximum rate of hydrogen generation for a g–C 3 N 4 –based ternary nanocomposite ever seen when exposed to whole solar spectrum and visible light (λ > 420 nm). This research provides fresh perspectives on the rational manufacture of metal-free g-C 3 N 4 based photocatalysts that will increase the conversion of solar energy. By reusing the used 3CP/Cd/g-C 3 N 4 photocatalyst in five consecutive runs, the stability of the catalyst was investigated, and their individual activity in the H 2 production activity was assessed. To comprehend the reaction mechanisms and emphasise the value of synergy between the three components, several comparison systems are built. Sphere-like Cu 3 P/CdS/g-C 3 N 4 photocatalyst was developed using hydrothermal route followed by ball milling and wet impregnation assisted method. A highest hydrogen production of 125721 μmol h−1g−1 was obtained for the above nanocomposite containing 6.25 wt% of g-C 3 N 4. [Display omitted] • Sphere-like Cu 3 P/CdS/g-C 3 N 4 composites was developed for visible light activity. • Metal free composites for H 2 evolution under visible light illumination was achieved. • The improved charge separation, transfer and transport results highest H 2 production. • Best activity results are observed for 3CP/Cd-6.25CN catalysts supported on g-C 3 N 4. • First time we report highest H 2 production activity for Cu 3 P/CdS/g-C 3 N 4 composites. [ABSTRACT FROM AUTHOR]

The present study aimed at developing an exopolysaccharide based nanoemulsion with increased kinetic stability, solubility, and availability. The nanoformulation was fabricated employing ultrasonication, a high energy fabrication method and constituted of flaxseed oil, tween 80, ethanol, and exopolysaccharide (extracted from Ganoderma gibbosum). The resultant formulation was found to have an average droplet size of 101.5 nm, with a PDI of 0.189, and a zeta potential of -8.2 mV. The particle size was further confirmed via the high resolution transmission electron microscopy which reported the nanoemulsion droplets to be round, uniform in size, with particle size ranging between 10 to 115 nm. In terms of the thermodynamic and storage stability the formulation was found to be highly stable and resistant to creaming, phase separation, and changes in pH. Further, the results in-vivo antioxidant assay revealed an increase in the activity of serum superoxide dismutase and catalase and a decrease in the serum level of thiobarbituric acid reactive substances suggesting that the formulation is capable of ameliorating the effect of reactive oxygen species in biological system. [ABSTRACT FROM AUTHOR]

As traditional non-renewable energy sources become scarcer, researchers are exploring effective strategies for producing sustainable and renewable energy. Oxygen evolution reaction through electrocatalytic water splitting (EC-OER) on the surface of a semiconductor has drawn much more attention in the worldwide as it has the principal role towards the several kind of energy applications viz. fuel cell, metal-ion rechargeable batteries and water oxidation. It is extremely difficult to develop eco-friendly, plentiful, and cost-effective nanomaterials as catalysts in order to achieve high efficiency of hydrogen production through water splitting. Furthermore, hierarchical nanostructures will become more valuable in future energy conversion applications due to their excellent physicochemical properties. Herein, we have synthesized total six different kinds of multi-metal-doped porous silica nanomaterials by utilizing the combination of nickel, iridium, and ruthenium metal slats in order to explore them as potential catalysts for electrochemical water oxidation process. We present a simple strategy to synthesize multi-metal-doped silica materials with spherical morphology, deploying a cation surfactant template (CTAB) as a structure directing agent in water-ethanol solvent mixtures. These materials are thoroughly characterized with the help of powder X-ray diffraction (PXRD), UV–Vis, FT-IR, X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscopy (FE-SEM), nitrogen-sorption isotherm, thermogravimetric (TGA) analysis. The particles are 550–600 nm in size with a fine-looking spherical morphology and surface area in the range of 111–419 m2/g. Among all of these metal-silica, Ni–Ir–Ru-doped mesoporous silica particles (NIRS) exhibit excellent electrocatalytic activity towards oxygen evolution reaction (100 mA/cm2 current density@0.5V) with long-term durability up to 10 h, and the Tafel slope is also very low (∼68 mV/dec) in 1 M KOH medium. The excellent electrical conductivity of Ni–Ir–Ru-doped silica makes it a superior electrocatalyst due to its spherical morphology, synergistic effects of the multi metallic components, and its hierarchical nanoporous structure. [Display omitted] • A facile method for multi-metal-doped mesoporous silica was developed. • The particle sizes were 550–600 nm and surface area were up to 419 m2/g. • Multi-metal-doped mesoporous silica particles were spherical particles. • NIRS generated 100 mA/cm2 and current density@0.5V during OER in pH=14. • NIRS exhibited high durability up to 10 h with Tafel slope of 68 mV/dec in pH=14. [ABSTRACT FROM AUTHOR]

Li–CdS/TiO 2 nanocomposite with different composition 10Li–CdS/TiO 2 , 20Li–CdS/TiO 2 , 30Li–CdS/TiO 2 , 40Li–CdS/TiO 2 , 50Li–CdS/TiO 2 were coated on FTO surface by using doctor blade followed by successive ionic layer adsorption and reaction (SILAR) method. As synthesized Li–CdS/TiO 2 photoanode is characterized with field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), high resolution transmission electron microscopy (HR-TEM), diffuse reflectance spectroscopy (UV-DRS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL). FE-SEM analysis suggests that, Li–CdS/TiO 2 film is 10.2 μm thick, porous, spongy and uniformly covered on FTO surface. The HR-TEM images reveal that the CdS nanoparticles are in intimate contact with the TiO 2 nanocrystal shells with the CdS/TiO 2 interfaces and the particle size of CdS and Li 2 S lies in the range of 20 nm–50 nm. UV-DRS analysis shows that, as the loading of Li in CdS/TiO 2 films increases, there is decrease in band gap energy. The XPS analysis supports the presence of Li+ in Li–CdS/TiO 2 nanocomposite. The PL spectra suggest that, with the increase in extend of Li+ ions into Li–CdS/TiO 2 , intensity of green emission band increases and it is shifted to higher wavelength. This reflects the low recombination rate of photo generated charge carrier in Li–CdS/TiO 2 which is responsible for higher photocatalytic H 2 production. The visible light photoanodic performance of Li–CdS/TiO 2 was investigated for H 2 evolution using aqueous Na 2 SO 3 and Na 2 S solution under natural sunlight. Among the all-synthesized nanocomposite material, the highest amount of hydrogen produced over 20Li–CdS/TiO 2 was found to be 38.61 ml/g/h in natural sunlight. Photoelectrochemical (PEC) performance of Li–CdS/TiO 2 was examined. A possible mechanism for photocatalytic hydrogen generation is also discussed. • Li–CdS/TiO 2 function as photocatalyst cum photoanode during solar water splitting. • Li–CdS/TiO 2 photoanode was synthesized by doctor blade followed by SILAR method. • Li–CdS/TiO 2 photoanode produces excellent H 2 as compare to TiO 2 and CdS/TiO 2. • In natural sunlight, 38.69 ml/g/h H 2 were evolved over 20Li–CdS/TiO 2. • 20Li–CdS/TiO 2 shows excellent transfer kinetics in PEC water splitting process. [ABSTRACT FROM AUTHOR]

In the present work, bio-based conductive polymer composites were developed to utilize as supporting material for anode catalysts for oxidation of fuels to generate electrical energy. An in-situ method was adopted to synthesize the conducting polymer carbon composites through combined condensation process by reacting terephthalaldehyde and benzidine, and reinforced with almond shell carbon (BT-ASC). Using formaldehyde reduction method platinum-tin nanoparticles were deposited on BT-ASC composites and were characterized using modern analytical instruments., viz., X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDAX) and Fourier transform infrared spectroscopy (FT-IR). Thermal stability of the conducting polymer composites was analyzed by thermogravimetric analysis (TGA). The electrochemical properties of the prepared catalysts were studied by cyclic voltammetry and chronoamperometric analyses. Data obtained from different studies inferred that the Pt–Sn/BT-ASC catalyst possesses the maximum current density (88.6 mA/mg) with minimum oxidation potential than those of Pt–Sn/ASC, Pt/BT-ASC and Pt/ASC catalysts. The present work ascertains the importance of conducting polymer composites developed using reinforced with bio-carbon towards electro-oxidation of methanol and these supporting materials possess an enhanced catalytic activity than that of reported catalysts. • A bio-based conductive polymer composites as supporting material for anode catalysts. • Pt and Pt–Sn nanoparticles were developed by simple chemical reduction method. • Deducing jf/jb ratio, surface area and catalytic activity relationship of catalysts. • PtSn/BT-ASC, higher surface area and excellent catalytic activity. • PtSn/BT-ASC catalyst material for methanol fuel oxidation in acidic medium. [ABSTRACT FROM AUTHOR]

Noble metal single-atom catalysts (SACs) have been extensively investigated due to their unique electronic structure and high-efficiency catalytic performance. However, there are relatively few studies on the preparation of non-noble metal single atoms and their application in oxygen evolution reaction (OER). In this paper, nickel single-atom catalyst was prepared using a facile one pot method. Ni-SAC-2.5% showed uniform SACs distribution and anti-ferromagnetic property as evidenced by the aberration-corrected high resolution electron microscopy and the first-principle calculations, achieving the lowest overpotential of 220 mV (10 mA/cm2) and stable performance in 1 M KOH solution. Meanwhile, it exhibited the largest specific capacitance value of 1.77 mF/cm2 and the lowest charge transfer resistance value of 40.75 Ω due to the accelerated kinetic process. First-principle calculations further confirmed the lowest computed overpotential of 0.54 eV for Ni-SAC-2.5%. However, Ni small clusters and nanoclusters with superparamagnetic performance were observed when the Ni content was further increased to 3.5% and 4.5%, resulting in higher overpotentials of 0.85 eV and 2.01 eV for OER process as indicated by the theoretical simulation. This paper provides a facile method to prepare non-noble metal SACs and useful guidance for designing high performance OER catalysts. • Nickel single-atom catalyst was prepared using a facile one pot method. • Ni-SAC-2.5% showed uniform SACs distribution and anti-ferromagnetic property. • Ni-SAC-2.5% exhibited the lowest overpotential of 220 mV (10 mA/cm2) for OER process. • Ni-SAC-2.5% exhibited the largest specific capacitance value of 1.77 mF/cm2. • First-principle calculations confirmed the lowest overpotential of 0.54 eV for Ni-SAC-2.5%. [ABSTRACT FROM AUTHOR]

In this study, a novel cobalt-doped cerium oxide (CeO2)on reduced graphene oxide (rGO) substrate was successfully prepared through a hydrothermal method. The comprehensive characterization of the synthesized nanocomposite involved X-ray diffraction studies (XRD), Raman spectrum analysis, High Resolution Transmission Electron microscopy (HRTEM), and Field Emission Electron Microscopy (FE-SEM). The effective surface area of CeO2/rGO and Co-CeO2/rGO was determined using the Randles-Sevecik equation, revealing values of 4.02X10-5 cm2 and 6.35X10-5 cm 2, respectively. Cyclic Voltammetry (CV) was employed to investigate the electrochemical reversibility behavior, demonstrating promising results for Co-CeO2/rGO nanocomposite. Electrochemical impedance spectroscopy(EIS) further highlighted low charge transfer resistance (Rct) and enhanced double-layer capacitance (Cdl). Notably, the synthesized nanocomposite exhibited excellent electrocatalytic activity for methanol and formic acid oxidation in an acidic medium. Overall, this work provides valuable insights into the synthesis characterization, and electrochemical performance of Co-CeO2/rGO nanocomposite, showcasing their potential applications in energy-related processes. [ABSTRACT FROM AUTHOR]

The high explosive PBX 9502 undergoes irreversible expansion during thermal cycling ("ratchet growth"). Recent innovations in thermomechanical modeling via homogenization strategies are beginning to incorporate mesoscale information such as grain size, total porosity, and spatial distribution of voids and cracks. To generate a complete experimental data set to challenge and inform these models, PBX 9502 pellets were thermally cycled, cross-sectioned using ion polishing, and imaged in high resolution with scanning electron microscopy. Ratchet growth was found to drive expansion through microcracking. Microcracks were affected by agglomeration of crystals within the PBX. Virgin material showed greater ratchet growth than recycled material. [ABSTRACT FROM AUTHOR]

The microstructure of nanostructured bainite formed by austempering in high-carbon silicon steel is characterized by high resolution electron microscopy. The results show that the bainitic sheaves consist of nanoscale subunits. The found kinds of crystal lattice distortions of each subunit in one bainite lath show clear difference. The latest generated subunit has most distortions. As the subunit grows up, the lattice distortion gradually gets relaxed. This indicates that the subunits form with high phase transformation strain energy, which causes severe lattice distortion. The results provide new experimental evidence on subjects relevant to the understanding of the mechanism of formation of bainitic ferrite. [ABSTRACT FROM AUTHOR]

Herein we demonstrated the preparation of sulphur-doped graphene (SG) prepared via hydrothermal route. The resulted material is used for making highly sensitive and selective electrochemical sensor platform for accurate quantification of Hydrogen Peroxide (H2O2). Structural features and surface morphology of synthesised materials are fully examined using High resolution Transmission electron microscopy (HRTEM), Scanning electron microscopy (SEM), FT-IR and Raman spectroscopy techniques. In addition to that, electrochemical techniques like cyclic voltammetry (CV) and chronoamperometry (CA) are used to quantify the electron transfer kinetics and electro catalytic activity, these results inveterate it is due to strong electron donating ability of doped sulphur (S) atom and edge plane sites in SG that promotes the electron transfer process at electrode-electrolyte interface. The SG modified glassy carbon electrode (SG/GCE) exhibited finite selectivity; sensitivity stability with a regression coefficient (R2) value is 0.99 towards H2O2 estimation. The above observation conclude that these results are finest report to scrutinise the electrochemical properties of Graphene network by doping with Sulphur atom and it served as an important benchmark for the development of inexpensive SG based sensor platforms for electrochemical biosensor applications. [ABSTRACT FROM AUTHOR]

The heating characteristics of citrate-coated magnetite nanoclusters in a magnetic inductive system were analyzed with several methods, such as the numerical initial slope method, a fourth-degree polynomial, a single Box-Lucas equation, a sum of two and three Box-Lucas equations, the corrected slope method and its extension. The Box-Lucas equation was modified by considering a half-rate heating constant (λ1/2) rather than the traditional heating-rate constant (λ), which is usually presented in the literature. The nanoclusters, produced by the precipitation method were characterized with high resolution transmission electron microscopy, X-ray diffraction, Mössbauer spectroscopy, thermogravimetric analysis and Fourier transform infrared spectrometry. High resolution transmission electron microscopy showed the nanoclusters of the synthesized magnetic particles. According to the X-ray diffraction data, these nanoclusters had average particle sizes ranging from 20 to 31 nm and comprised magnetite. Mössbauer spectroscopy showed the characteristic double magnetic pattern associated with the iron ions located at the A and B sites of the inverse spinel crystal structure for magnetite. Infrared peaks such as those at 1629 cm−1 and 564 cm−1 for the citrate-coated magnetite nanoclusters, suggested that citrate ions were indeed attached to the particle surfaces. Additionally, a thermogravimetric analysis showed that from 4.6 to 10.9 wt% citrate ions were attached to the particle surfaces. Both the modified Box-Lucas equation and the extension of the corrected slope method provided consistent results and greatly simplified estimation of the specific absorption rate of the magnetite nanoclusters used in the magnetic fluid hyperthermia studies. [ABSTRACT FROM AUTHOR]

Cu–Ni/SiO2 catalysts were prepared by coprecipitation method and used in the dehydrogenation reaction of secondary butyl alcohol to methyl ethyl ketone (MEK). The crystal structure, reduction characteristics, element valence state and dispersibility of the catalysts were investigated using X-ray diffraction (XRD), hydrogen temperature-programmed reduction (H2-TPR), inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectroscopy (XPS), X-ray Auger electron spectroscopy (XAES) and high resolution transmission electron microscopy (HRTEM). The role of Ni component in the dehydrogenation reaction of secondary butyl alcohol was analyzed. The results showed that the conversion of secondary butyl alcohol increased to over 99% when using the Cu–Ni/SiO2 catalyst. The addition of nickel component to Cu/SiO2 inhibited the agglomeration of copper nanoparticles. The interaction between copper and nickel was strengthened due to the formation of the Cu–Ni compound. This resulted in change to the valence state and improved the dispersion of copper species on the catalyst surface. The Cu+/(Cu+ + Cu0) ratio increased with the addition of nickel component to Cu/SiO2, which may be responsible for the enhancement of the secondary butyl alcohol conversion. However, the addition of the nickel component increased the reduction temperature of the catalysts and deteriorated their reduction characteristics, which leads to insufficient reduction, resulting in a high content of Cu+ species remaining in the catalyst. Therefore, side reactions can occur, which are detrimental to the selectivity and yield of MEK. The selectivity to MEK can reach 98% with the Cu/SiO2 catalyst, whereas that for the Cu–Ni/SiO2 catalyst was 97%. [ABSTRACT FROM AUTHOR]

Sn3O4 are promising semiconductor materials due to their visible light absorption ability. In this work, a series of materials, such as SnO2, Sn3O4 and Sn3O4/SnO2 heterostructures, with different phase ratios were prepared using hydrothermal synthesis. The materials were characterized using X-ray diffraction (XRD), Raman and diffuse reflectance spectroscopy (DRS), high resolution transmission electron microscopy (HRTEM), nitrogen adsorption (BET). Flat-band potentials (EFB) of the samples were determined using the photocurrent onset potential (POP) method. It was shown that the potentials obtained with open circuit potential measurements versus illumination intensity (OCP) likely corresponded to the EFB of SnO2 nanoparticles in heterostructures due to interfacial electron transfer from the conducting band of Sn3O4 to that of SnO2. The photo-electrooxidation processes of a series of organic substrates were studied in the potential range of 0.6–1.4 V vs. RHE under irradiation with ultraviolet (λ = 370 nm) and visible (λ = 450 nm) light. The Sn3O4 sample showed high activity in the photo-electrooxidation of acetone and formic acid in visible light. The Sn3O4/SnO2 samples exhibited noticeable activity only in the oxidation of formic acid. The presence of the SnO2 phase in the Sn3O4/SnO2 samples increased the photocurrent values under ultraviolet illumination, but significantly reduced the oxidation efficiency in visible light. [ABSTRACT FROM AUTHOR]

We have prepared CoNPs@CN that cobalt nanoparticles(CoNPs) dispersed uniformly in the carbon matrix Composite (CN) via a facile and controllable method. Samples were characterized by X-ray diffraction (XRD), UV–V spectroscopy, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). CoNPs@CN exhibited favorable photocatalytic activity under visible light irradiation. The results of quenching and photoluminescence experiments reveal the generation of main active species (•OH and •O 2 − radicals). The producing mechanism of active species can be attributed to that CoNPs@CN absorb photons and generate photogenerated electrons through localized surface plasmon resonance (LSPR) effect, then H2O and O2 in the solution react with the photogenerated hole and electrons to produce •OH and •O 2 − radicals. In the current study, CoNPs@CN are prepared that the cobalt (Co) nanoparticles dispersed uniformly in the carbon matrix via a facile and controllable method. Co@CN exhibited favorable photocatalytic activity under visible light irradiation. Co@CN can absorb photons under illumination through LSPR effect, thus the photogenerated electrons and holes were generated. H2O and O2 in the solution reacted with the photogenerated electrons to produce •OH and •O2– radicals. These two main radicals are used to decompose MO effectively. [ABSTRACT FROM AUTHOR]

Nano-glasses are next-generation scintillators combining favorably the merits of both scintillator crystals and glasses. Here, a new nano-glass scintillator is prepared embedding CsGd 2 F 7 :Ce3+ nanocrystals (NCs). The microscopic morphology, particle size, and distribution of the NCs are studied by high resolution transmission electron microscopy. Significantly enhanced radioluminescence efficiency is obtained in the nano-glasses. The largest integrable intensity of X-ray excited luminescence is 316% of the standard Bi 4 Ge 3 O 12 (BGO) crystal. A well-resolved full-energy peak with an energy resolution of 17.4% is registered for the 662 keV gamma rays, and the light yield is determined to be 827 ± 8 ph/MeV. The nano-glass scintillators exhibit good radiation hardness and thermal stability. As a proof of concept, an X-ray imaging system of a good resolution is built on the nano-glass scintillators. [ABSTRACT FROM AUTHOR]

Microstructural defects play a critical role in flourishing various properties of materials. Here in this article, the effect of Ag substitution on the various properties of CdS quantum dots (QDs) is studied. Ag doped CdS QDs are synthesized using chemical co-precipitation, a simple, cost-effective method suitable for mass-production. High resolution transmission electron microscopy (HRTEM) images show dopant induced change in density and types of microstructural defects. The development of multiple nanotwinning at the cost of stacking faults as well as single twin boundary via the substitution of Ag in CdS lattice is noticed. In present study, a strong quantum confinement is observed and confirmed by the crystallite sizes estimated via X-ray diffraction (XRD) and TEM studies. A systematic enhancement in the bandgap and reduction in crystallite size are observed with increasing concentration of dopant. The atomic concentration of element and chemical bonding in CdS QDs are studied using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) respectively. Unlike other elemental dopants, QDs when doped with Ag with the varying concentration exhibit a non-systematic emission behaviour with increasing concentration which is correlated to the microstructural defects and confinement strength. [ABSTRACT FROM AUTHOR]

In this report, we synthesized the neodymium-doped yttrium hydroxide nanobelts (Nd:Y(OH)3) using a facile route. The characterization methods, such as UV-Visible and photoluminescence spectroscopy, Raman, X-ray photoemission, Fourier transform infrared (FTIR) spectroscopy, and high resolution transmission electron microscopy (HRTEM), were applied to clarify the properties of the prepared colloidal sample. The structural characteristics of the prepared sample were analyzed via X-ray diffraction (XRD) and HRTEM. The average size of the hexagonal crystal is about 25 nm, which shows the compatibility of XRD and HRTEM spectroscopy results. Absorbance and emission spectra of the synthesized sample have demonstrated that the intensity of light emission by the colloidal sample is affected by the concentration of Nd3+ ions. In this research, it has been shown that the excitation of the samples with the wavelengths of 355 and 360 nm almost does not change the blue emission spectra because the wavelengths are related to the nature of the Nd+ 3, but with the excitation of 300 nm, the intensity of the emission spectra increases with the increase in the concentration up to 0.05 g (sample 2). [ABSTRACT FROM AUTHOR]

Metal hydroxides are extensively studied by researchers on account of the potential of these materials to be used in electrodes of energy storage devices. Remarkable electrochemical properties of nanostructured binary/ternary/quaternary metal hydroxides and their nanocomposites with carbonaceous materials prompted the investigation of these material groups for supercapacitor electrode applications. Zinc–aluminium binary hydroxide (ZAH) nanosheets and their nanocomposite with activated carbon (ZAH-AC) were synthesized by means of a hydrothermal method. X-Ray diffraction, selected area electron diffraction, Fourier transform infrared spectroscopy, and high resolution transmission electron microscopy were employed to study the basic characteristics of the synthesized samples. The electrochemical properties were studied using cyclic voltammetry, chronopotentiometry, and electrochemical impedance spectroscopy using a three-electrode system. At 1 A g−1 current density, ZAH and ZAH-AC nanosheets achieved specific capacitances of ∼159 F g−1 and ∼573 F g−1, respectively. A two-electrode system was utilized to confirm the workability of ZAH-AC as an electrode material. This system exhibited a high capacitance retention of 152% after 2000 charge–discharge cycles. The addition of AC to ZAH led to the enhancement of the specific capacitance without any crystal structural alterations in ZAH. The synergistic effect of the charge storage mechanisms of AC and ZAH resulted in a highly stable electrode material with pseudocapacitive behaviour. [ABSTRACT FROM AUTHOR]

A series of La3+ ion doped magnesium nickel ferrites, Mg 0.5 Ni 0.5 Fe 2-x La x O 4 (0 ≤ x ≤ 0.1) having a cubic spinel structure were prepared by the co-precipitation method. Various characterization techniques, including X-ray diffractometer (XRD), high resolution transmission electron microscopy (HR-TEM), electron spin resonance (ESR) and vibrating sample magnetometer (VSM) were used to investigate structural and magnetic properties. The average crystallite size decreases and lattice parameter increases with La3+ ion doping and lie in the range of 12–7 nm and 8.347–8.361 Å respectively. Analysis of ESR spectra reveals that, g-value with La3+ ion addition decreases from 2.57 to 2.12. The saturation magnetization and the coercivity decrease with increasing rare-earth content. Magnetic-hysteresis (M − H) loop shifts from a ferromagnetic to a superparamagnetic nature with La3+ ion addition. The dielectric study was carried out in the frequency range of 1 KHz to 4000 KHz and temperature ranging 30 °C–350 °C using the impedance analyzer. The dielectric constant decreases with increasing frequency and the La3+ ion concentration. The dielectric loss of the sample increases with increasing temperature. The magnetic properties of the synthesized nanoparticles make them a potential material for stable ferrofluid application and the low tangent loss value makes these material a potential candidate for frequency-based applications. [ABSTRACT FROM AUTHOR]

In this study, Boron Nitride Quantum Dots (BNQDs) are successfully synthesized via the hydrothermal method. Additionally, the hydrothermal method is employed to synthesize BNQDs decorated TiO2 nanograss (BNQDs/TiO2 NG) from BNQDs decorated TiO2 (BNQDs/TiO2). To validate the synthesis of different BNQDs samples, fluorescence spectroscopy (FL) is performed, revealing a strong quantum confinement effect resulting from variations in the precursor ratio. The bandgap energies of TiO2, BNQDs/TiO2, and BNQDs/TiO2 NG are determined using UV–Vis diffuse reflectance spectroscopy (UV-DRS), demonstrating a reduction in the band gap. A smaller band gap corresponds to a higher thermal conductivity, as there is a negative correlation between thermal conductivity and band gap energy. The study suggests that BNQDs/TiO2 NG exhibit higher thermal conductivity compared to TiO2 and BNQDs/TiO2. X-ray photoelectron spectroscopy (XPS) reveals the elemental composition of both BNQDs and TiO2, including Ti–O, B–N and B–O bonds. High Resolution Transmission Electron Microscopy (HR-TEM) is utilized to examine the morphological attributes of BNQDs/TiO2 NG. The crystalline structure of the synthesized composites is ascertained using X-ray diffraction (XRD). The photocatalytic degradation of methylene blue (MB) by TiO2, BNQDs/TiO2, and BNQDs/TiO2 NG under visible light is also compared. Based on the results, BNQDs/TiO2 NG is determined to be an effective material for treating wastewater containing organic dyes. [ABSTRACT FROM AUTHOR]

In place of the commercial Pt electrode used in quantum sensitized solar cells, the low-cost CuS cathode is created using electrophoresis. High resolution scanning electron microscopy and X-ray diffraction were used to analyze the structure and morphology of structural cubic samples with diameters ranging from 40 nm to 200 nm. The conversion efficiency of solar cells is significantly impacted by the calcination temperatures of cathodes at 100 °C, 120 °C, 150 °C, and 180 °C under vacuum. The fluorine doped tin oxide (FTO)/CuS cathode electrode reached a maximum efficiency of 3.89% when it was calcined at 120 °C. Compared to other temperature combinations, CuS nanoparticles crystallize at 120 °C, which lowers resistance while increasing electron lifetime. [ABSTRACT FROM AUTHOR]

We report different growth modes and corresponding magnetic properties of thin EuSe films grown by molecular beam epitaxy on BaF2, Pb1−xEuxSe, GaAs, and Bi2Se3 substrates. We show that EuSe grows predominantly in the (001) orientation on GaAs(111) and Bi2Se3, but along the (111) crystallographic direction on BaF2 (111) and Pb1−xEuxSe (111). High resolution transmission electron microscopy measurements reveal a sharp and highly crystalline interface for both (001) and (111) EuSe films. In agreement with previous studies, ordered magnetic phases include antiferromagnetic, ferrimagnetic, and ferromagnetic phases. In contrast to previous studies, we found a strong hysteresis of the antiferromagnetic–ferrimagnetic transition. The ability to grow epitaxial films of EuSe on Bi2Se3 and of Bi2Se3 on EuSe enables further investigation of interfacial exchange interactions between various phases of an insulating metamagnetic material and a topological insulator. [ABSTRACT FROM AUTHOR]

Protonic Ceramic fuel cells (PCFCs) hold great promise for many applications; however, their high operating temperature hinders their commercial use in practice. The crucial issue that limits the electrochemical performance of PCFCs (including oxygen and proton-ion-conducting) is the sluggish oxygen redox reaction (ORR) at the cathode surface at low operating temperatures. Herein, we have developed a C aFe 2 O 4 -WO 3 heterostructure composite by interface-vacancy engineered for an efficient ORR electrocatalyst for LT-PCFCs. The C aFe 2 O 4 -WO 3 heterostructure composite exhibits very low cathodic area-specific resistance (ASR) and high oxygen reduction reaction (ORR) activity response at low operating temperatures of 400–550 °C using a BaCe 0.7 Zr 0.2 Y 0.1 O 3-δ (proton-conducting) electrolyte. We have demonstrated high-power density of 585 ± 2% mW-cm−2 with a current density of 1660 mA-cm−2 at 550 °C with H 2 fuel and atmospheric air as oxidant and even with possible operation at 400 °C. Moreover, the CaFe 2 O 4 -WO 3 heterostructure composite shows a very low proton migration energy and activation energy compared to individual CaFe 2 O 4 and WO 3 , helping to promote ORR activity. Various spectroscopic measurements, such as X-ray diffraction, high resolution transmission electron microscopy (HR-TEM), U-visible spectroscopy (UV–visible), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations are employed to understand the interfacial properties for the improved ORR electrocatalytic activity of the CaFe 2 O 4 -WO 3 heterostructure composite cathode. Our obtained experimental and theoretical results can further help to develop functional cobalt-free electrocatalysts for LT-PCFCs. [Display omitted] [ABSTRACT FROM AUTHOR]

Syngas produced by catalytic partial oxidation (CPOX) of propane contains hydrogen (21.68%) and carbon monoxide (18.27%). Microtubular solid fuel cells (μT-SOFCs) were fabricated and tested with syngas and pure hydrogen respectively. The open-circuit voltage (OCV) is 1.02 V, and the maximum power (MP) of microtubular solid fuel cell is 7.07 W at 700 °C with syngas/air. After operating in syngas/air for 100 h, the voltage declined 4.5%. A few sites of anode separate from electrolyte, particularly, some few nanometers nickel (Ni) particles have precipitated at the interface of electrolyte/anode. Comparing to Ni grain with 200 nm-1 μm diameter in rest sites of anode, it is easy to explain the loss of Ni and the separation of anode with electrolyte. Meantime obvious carbon deposition is found at the pores after 100 h working in syngas/air. There are other impurity phases discovered by high resolution transmission electron microscopy (HRTEM) at a triple phase boundary (TPB) of electrolyte and anode. • Nano-domains of nickel are expelled as clusters from anode into amorphous oxidized phase. • The loss of nickel causes to the difference of nickel grain size. • The structure of anode is destroyed by the growth of carbon at 700 °C. • The triple phase boundary degenerates towards the double phase boundary for long-term working. [ABSTRACT FROM AUTHOR]

The discovery of nanoparticles with varied size, shape and composition has stretched the limits of nanotechnology in almost any field. One of the important areas of interest is the use of nanoparticles in heterogeneous catalysis, whereby it offers an advantage by providing large surface area. Our present work focussed on the development of a graphene-based nanocatalyst (Pd@NGO) as an efficient tool to study various organic transformations. The prepared mesoporous catalyst was characterised by X-ray diffraction (PXRD), thermogravimetric analysis (TGA), field emission-scanning electron microscopy (FE-SEM), Brunauer–Emmett–Teller (BET), high resolution transmission electron microscopy (HR-TEM) and Fourier transformer infrared spectroscopy (FT-IR), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and X-ray photoelectron spectroscopy (XPS). TEM images showed the light grey sheets of N-GO on which Pd(0) nanoparticles were immobilised. BET analysis confirmed the mesoporous texture of the designed nanocatalyst by giving the surface area of 12.933 m2 g−1 with a pore volume and average pore diameter of 0.020685 cm3 g−1 and 6.39 nm, respectively. Also, FTIR data affirmed the presence of a characteristic C–N peak near 1271 cm−1 showing successful doping of nitrogen over graphene oxide. The XPS data revealed the presence of various elements like carbon (C 1s), nitrogen (N 1s), oxygen (O 1s) and Pd 3d. The prepared nanocatalyst was explored in Suzuki coupling reaction under green conditions, reduction of nitro compounds and the photodegradation of methyl orange with a degradation efficiency of 98.77%. The photodegradation of dyes is viewed as a potential method for the treatment of industrial wastewater due to its low cost, ecologically acceptable procedure, and lack of secondary contamination. Through direct photodegradation or a degradation process involving sensitization, this approach exhibits the light-enhanced creation of charge carriers and reactive radicals that non-selectively break down a variety of organic dyes into water, CO2, and other organic molecules. Moreover, Pd@NGO shows excellent stability and can be used multiple times, and hence possesses efficient reusability. [ABSTRACT FROM AUTHOR]

A key challenge encountered by printed electronics is that the conductivity of sintered metal nanoparticle (NP) traces is always several times smaller than the bulk metal conductivity. Identifying the relative roles of the voids and the residual polymers on NP surfaces in sintered NP traces, in determining such reduced conductivity, is essential. In this paper, we employ a combination of electron microscopy imaging and detailed simulations to quantify the relative roles of such voids and residual polymers in the conductivity of sintered traces of a commercial (Novacentrix) silver nanoparticle-based ink. High resolution transmission electron microscopy imaging revealed details of the morphology of the inks before and after being sintered at 150 °C. Prior to sintering, NPs were randomly close packed into aggregates with nanometer thick polymer layers in the interstices. The 2D porosity in the aggregates prior to sintering was near 20%. After heating at 150 °C, NPs sintered together into dense aggregates (nanoaggregates or NAgs) with sizes ranging from 100 to 500 nm and the 2D porosity decreased to near 10%. Within the NAgs, the NPs were mostly connected via sintered metal bridges, while the outer surfaces of the NAgs were coated with a nanometer thick layer of polymer. Motivated by these experimental results, we developed a computational model for calculating the effective conductivity of the ink deposit represented by a prototypical NAg consisting of NPs connected by metallic bonds and having a polymer layer on its outer surface placed in a surrounding medium. The calculations reveal that a NAg that is 35%–40% covered by a nanometer thick polymeric layer has a similar conductivity compared to prior experimental measurements. The findings also demonstrate that the conductivity is less influenced by the polymer layer thickness or the absolute value of the NAg dimensions. Most importantly, we are able to infer that the reduced value of the conductivity of the sintered traces is less dependent on the void fraction and is primarily attributed to the incomplete removal of the polymeric material even after sintering. [ABSTRACT FROM AUTHOR]

For a long time, it was unclear how the myriads of microtubules are generated in a spindle to orchestrate cell division. In recent years, many microtubule nucleation pathways that generate spindle microtubules have been identified and shed light on this question. Moreover, the γ-tubulin ring complex (γ-TuRC), once thought to be the cell's sole nucleator, is now known to work synergistically with the protein XMAP215/ch-TOG. Recent high resolution cryogenic electron microscopy structures and in vitro single molecule studies of γ-TuRC provided clues towards its mode of action. It is an emerging concept that biomolecular condensation plays a role in microtubule nucleation in the spindle. The next challenge will be to determine how γ-TuRC is targeted to the right location in the spindle at the right time and subsequently turned on to generate the spindle framework. The cell orchestrates the dance of chromosome segregation with remarkable speed and fidelity. The mitotic spindle is built from scratch after interphase through microtubule (MT) nucleation, which is dependent on the γ-tubulin ring complex (γ-TuRC), the universal MT template. Although several MT nucleation pathways build the spindle framework, the question of when and how γ-TuRC is targeted to these nucleation sites in the spindle and subsequently activated remains an active area of investigation. Recent advances facilitated the discovery of new MT nucleation effectors and their mechanisms of action. In this review, we illuminate each spindle assembly pathway and subsequently consider how the pathways are merged to build a spindle. [ABSTRACT FROM AUTHOR]

Geogenic arsenic has become a globally-distributed groundwater contaminant, liberated from the weathering of arsenic-bearing sulfide minerals and often transported to aquifer sediments adsorbed to iron oxides. Among the iron oxides, goethite (α-FeOOH) is uniquely important for the fate of arsenic because of its widespread abundance, stability, and high affinity for binding arsenic. Goethite is ubiquitous in soils and sediments and often contains substituted elements, including manganese. Structural manganese may affect the surface reactivity and redox capacity of goethite and alter the mechanisms of recrystallization catalyzed by dissolved Fe(II), potentially affecting arsenic adsorption. This study examined the fate of As(V) during the interactions between dissolved Fe(II) and Mn-substituted goethites at pH 4 and 7 as well as associated changes in arsenic speciation. At pH 7, the addition of dissolved Fe(II) initially increases the adsorption of As(V) onto Mn-bearing and Mn-free goethites. For the Mn-substituted goethites, the adsorbed As(V) slowly releases to solution at longer aging times. Fe(II) addition at pH 4 slightly increases As(V) uptake by Mn-substituted goethites, with differences in total sorption correlating with the Mn content in goethite. The addition of Fe(II) releases substantial dissolved manganese but the amount solubilized is higher at pH 4 compared to 7, suggesting that the presence of adsorbed As(V) may substantially promote the Mn release at pH 4. X-ray absorption fine structure spectroscopy shows that arsenic is stabilized as As(V) in all the samples and adsorbed on goethite via a bidentate binuclear mechanism. Fitting results show that the binding distance and coordination numbers are stable in Mn-free goethite and Mn-substituted goethite samples; the effect of substituted Mn on the surface complex structure is minor. High resolution transmission electron microscopy and X-ray diffraction confirm that no secondary ferrous arsenate minerals precipitate under both pH conditions. This study improves our understanding of the Fe(II)-As(V) interactions on iron oxides, and demonstrates that the substituted cations such as manganese may quantitatively alter the geochemical fate of arsenic during the reaction of dissolved Fe(II) with Fe(III) oxides. [ABSTRACT FROM AUTHOR]

Many researchers have shifted their interest towards eco‐friendly, cost effective, and environmental‐based metal oxide nanoparticles. Herein, Cu2O nanoparticles are synthesized via green method for water splitting application. The prepared materials are characterized structurally and morphologically by field emission‐scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X‐ray photoelectron spectroscopy (XPS) Raman, and UV–visible spectroscopy. It is found that size and morphology depend strongly on OLE concentration and reaction time. The temperature increase leads to the formation of copper oxide (CuO) nanoparticles, which exhibit quantum confinement behavior and have an optical band gap that increases with decreasing size. Photoelectrochemical (PEC) tests of the coated graphite with Cu2O nanoparticles show a severe instability of Cu2O under irradiation due to the oxidation state that can easily change. For that, a protective overlayer of cuprous sulfide Cu2S is successfully grown on the top of Cu2O nanostructures to stabilize the photocathode. After Cu2S deposition, the measured photocurrent is significantly improved. Thus, this material is very promising for hydrogen generation by water splitting. [ABSTRACT FROM AUTHOR]

Transition metal borides have great potential to be low-cost, high-performance catalysts for novel energies despite the synthesis is rather difficult. In this paper, the reduced graphene oxide (rGO) supported iron boride (Fe 2 B/rGO) based catalysts are synthesized by a facile reduction method. The successful synthesis of Fe 2 B is confirmed by X-ray diffraction, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray photo-electron spectroscopy (XPS) and other tests. HRTEM tests showed that the constructed Fe 2 B was embedded in the rGO, where B played the role of coordination atoms which could regulate the electronic structure of the catalysts and improve the catalytic performance towards oxygen reduction reaction (ORR). The electrochemistry tests showed that the peak current intensity of the Fe 2 B/rGO catalyzed ORR could be reached up to 7.6 mA/cm2, which surpassed that of the Pt/C (20 wt%) catalyst. The current intensity can be kept at 82.47% after continuous running 20,000 s, which is higher than the Pt/C catalyst (79.4%). The onset potential reaches up to 0.95 V, which is only 0.06 V lower than that of Pt/C (20 wt%) catalyst. Both RDE and RRDE tests confirmed that the Fe 2 B/rGO catalyzed ORR major happed through 4-electron pathway. The redistributed electron between iron and boron atoms promoted the happening of ORR on Fe 2 B/rGO catalysts. The results of this work provide a novel way to develop high performance transition metal boride based catalysts for ORR. [Display omitted] • Fe 2 B based catalysts for ORR with the onset potential of 0.06 V was synthesized. • Peak current intensity of Fe 2 B/rGO catalyzed ORR was above that of Pt/C catalyst. • The reaction mechanism of iron-boride catalyzed ORR was illustrated. • Metal-boride materials have great potential to be high performance ORR catalysts. [ABSTRACT FROM AUTHOR]

This work studies the influence of the 2-hydroxyethylammonium acetate (2-HEAA) ionic liquid (IL) as an electrolyte in the electrochemical anodization of titanium for the synthesis of nanostructures for photoelectrochemical water splitting. Different 2-HEAA IL concentrations were used ranging from 0 to 4% v/v (IL-0 to IL-4) in electrolytes containing NH 4 F, water and ethylene glycol. Morphological, structural and electrochemical characterization of the nanostructures was carried out by means of field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), and Mott-Schottky (MS) analysis. Additionally, photoelectrochemical tests were carried out in order to evaluate the efficiency of these materials as catalysts for water splitting applications. According to the obtained results, the electrolyte used for electrochemical anodization should contain little amount of NH 4 F (0.05 M) in order to obtain efficient nanostructures for photoelectrochemical purposes. However, small concentrations of IL (IL-0.25) resulted in nanostructures with higher photocurrents than doubling the NH 4 F concentration to 0.1 M. Therefore, the IL addition contributes to a more sustainable electrolyte formulation. The best photoelectrochemical response for water splitting processes was obtained for the nanostructures anodized with 1% v/v of 2-HEAA IL (IL-1) due to their high surface/area (higher pore diameters, smaller nanotubes wall thickness and higher nanotubes lengths), better crystallinity and electrochemical response, showing photocurrents more than 100% higher than the ones obtained for the nanotubes anodized without IL. [ABSTRACT FROM AUTHOR]

Metal halide-perovskite-quantum dots (MH-PQDs) have gained wide attention due to their tunable optoelectronic properties and better stability against the ambient environment compared to organometal halide-based PQDs. The stability of the perovskite QDs is of utmost importance, considering their application in light emitting diodes and photodetectors. Herein, we have systematically analyzed the stability of perovskite QDs and have fabricated a photodetector device by using the most stable Mn2+:CsPb(Br1−xClx)3 QDs. The manuscript discusses the synthesis of CsPbBr3 QDs and manganese (Mn) doped Mn2+:CsPb(Br1−xClx)3 QDs using the ligand-assisted re-precipitation (LARP) technique and have studied the correlation between various dopant concentrations and stability. Different concentrations of Mn2+ doping (0.7, 1, 1.5, and 3 mmol of MnCl2·4H2O) in CsPb(Br1−xClx)3 QDs were investigated to study the stability by aging and the optimum concentration of Mn2+ that could be doped into CsPb(Br1−xClx)3 QDs which offered better stability concerning its photoluminescence was found. The optical properties of the synthesized QDs were characterized using UV-Vis absorbance, photoluminescence (PL), and time resolved photoluminescence spectroscopy (TRPL) techniques. The formation of CsPbBr3 QDs with a size of 25.80 ± 3.69 nm and Mn2+:CsPb(Br1−xClx)3 QDs with a size of 22.65 ± 3.28 nm was confirmed by using the high resolution transmission electron microscopy (HR-TEM) technique. TRPL analysis revealed the d–d emission of the Mn2+:CsPb(Br1−xClx)3 QDs at 600 nm due to Mn2+ doping. Furthermore, the self-powered photodetector device was fabricated by using stable 0.7 mmol Mn2+-doped CsPb(Br1−xClx)3 QDs and achieved a quick response, such as a rise time (ton) of 438 ± 8 ms and fall time (toff) of 592 ± 11 ms under one sun illumination. This work could be useful in the field of optoelectronics, especially in the study of doped semiconductor QDs. [ABSTRACT FROM AUTHOR]

The present study was focused on green synthesis of Silver nanoparticles (AgNPs) using Trigonella foenum‐graceum L. seed extract belonging to specific variety HM (Hisar Mukta) 425, optimizing the different experimental conditions required for the formation and stability of AgNPs. UV‐Vis spectroscopy, Particle Size Analyzer (PSA), Field Emission Scanning Electron Microscopy (FESEM), High Resolution Transmission Electron Microscopy (HRTEM), X‐ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) were used to characterise the synthesised AgNPs. The average size of AgNPs was found to be 22 nm and were spherical in shape. Additionally, the United States Environmental Protection Agency (USEPA) has listed nitrophenols as a priority pollutant, and biosynthesized AgNPs can catalytically convert them into less harmful aminophenols. One example of a reaction where AgNPs are used as a catalyst is the conversion of p‐nitrophenol to p‐aminophenol, which acts as a bridge for many analgesics and antipyretic medications. Hence, the study is anticipated to have a significant impact on the pharmaceutical, cosmetic, and food industries. [ABSTRACT FROM AUTHOR]

We have determined the proton, electrolyte (NaNO 3) and arsenate affinity constants on the corresponding surface sites of goethite. An empirical optimization approach was applied using the Charge Distribution Multisite Complexation (CD-MUSIC) model, initially, by simulating an extensive proton adsorption data set obtained from four goethites of specific surface areas (SSAs) spanning from 43 to 89 m2/g. Each goethite showed different crystal face compositions, which were measured previously from independent high resolution electron microscopy observations. Only the capacitance value was left as an additional optimizing parameter. For arsenate adsorption, with the above optimized values fixed, the contributing surface arsenate complexes and their respective affinity constants and charge distributions (CD) were also optimized. A unified set of affinity and CD parameters was obtained, where the only resulting variables among goethites were the capacitance 1, the specific surface area and the crystal face contributions (and thus their reactive surface site densities). It was found that the site density parameter is decisive when data show adsorption maxima, such as in the arsenate adsorption isotherms. The self-consistent modeling approach yielded pKa values of singly-coordinated sites of 8.82, and of triply-coordinated sites of 9.65. Three surface arsenate complexes bound only to singly-coordinated sites were found to describe all experimental data, although only two of them were predominant across the pH and As(V) concentration ranges investigated: a bidentate non protonated (BD) complex, and a protonated monodentate (HMD) one. Charge distribution of surface arsenate complexes was found to significantly influence the optimizations, but increased values of optimized capacitance 1 were found to compensate for previously underestimated surface site density values, to yield almost identical surface affinity and CD parameters. Finally, correlations found between surface site density and capacitance-1 parameters with SSA expanded the applicability of the modeling approach presented, to other goethites with different SSAs than the ones investigated here. [ABSTRACT FROM AUTHOR]

Liquid cell electron microscopy (LCEM) has long suffered from irreproducibility and its inability to confer high-quality images over a wide field of view. LCEM demands the encapsulation of the in-liquid sample between two ultrathin membranes (windows). In the vacuum environment of the electron microscope, the windows bulge, drastically reducing the achievable resolution and the usable viewing region. Herein, we introduce a shape-engineered nanofluidic cell architecture and an air-free drop-casting sample loading technique, which combined, provide robust bulgeless imaging conditions. We demonstrate the capabilities of our stationary approach through the study of in-liquid model samples and quantitative measurements of the liquid layer thickness. The presented LCEM method confers high throughput, lattice resolution across the complete viewing window, and sufficient contrast for the observation of unstained liposomes, paving the way to high-resolution movies of biospecimens in their near native environment. [ABSTRACT FROM AUTHOR]