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In the present work, the doping effect of Zn2+ ion (varying doping concentrations in the range of 0 %–30 %) on PbO nanoparticles (NPs) has been investigated proficiently. This study aims at in-depth analysis of the structure-property relationships of the sol-gel derived Zn doped PbO (Pb 1- x Zn x O) NPs, especially the vacancy evolved properties and the luminescence properties. The X-ray powder diffraction (XRD), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), field emission scanning electron microscopy (FESEM) and Fourier-transform infrared (FT-IR) spectroscopic characterization analyses justified the nanocrystallinity of the Pb 1- x Zn x O powdered NPs while the mean crystallite sizes were located in between 12 and 36 nm range. Williamson – Hall (W – H) method revealed a monotonous increase of the lattice strain which is compatible with the decrease of NPs' crystallite size by increase in the Zn2+ doping level. The replacement of Pb2+ ions with the Zn2+ ions caused the reduction of crystallite size by the higher Zn2+ doping level. Prominent peaks of Zn, Pb and O elements are noticed in energy dispersive X-ray spectroscopic (EDS) characterization. The elemental distributions of the chemicals present in the NPs were explored by the elemental mapping analysis. The optical absorption (OA) analysis indicated that the energy band gap (E g) can be estimated to be 2.21, 2.36, 2.55 and 2.70 eV for 0, 10, 20 & 30 % Zn doped PbO NPs, respectively. The positron annihilation lifetime (PAL) spectroscopic studies evidenced the presence of vacancy type defects within the NPs and an increase in defect concentrations has been observed by the increase in Zn concentrations. The photo-induced fluorescence (FL) emission spectra exhibited three luminescence peaks around the wavelengths 430 nm, 490 nm and 522 nm for all the NPs. The observations suggested the possibility of tailoring the characteristics of the synthesized NPs for practical applications in the field of optoelectronics. [ABSTRACT FROM AUTHOR]

The vast use of silver nanoparticles (AgNPs) in rapidly growing number of biomedical applications and sensing has given the importance of different synthetic methods for the preparation of AgNPs. Threre are lots of effective synthetic procedure that are lacking to synthesize nanoparticles with maintaining proper size and shape in colloidal medium. Here in this article synthesis of colloidal AgNPs and its characterization is described. The sizes of the synthesized AgNPs were of about 16±2nm. Some important modern techniques like UV-Vis spectroscopy, powdered X-ray diffraction (XRD), Scanning electron microscopy (SEM), High resolution transmission electron microscopy (HRTEM) were used for proper characterization synthesized colloidal AgNPs. Silver nitrate (AgNO3) and sodium borohydride (NaBH4) were used to synthesize colloidal AgNPs where the later one plays vital dual role by reducing AgNO3 and giving stabilization of synthesized nanoparticles. [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]

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]

Bismuth ferrite with manganese doping (BiFe0.95Mn0.05O3 or BFMO) and bismuth ferrite with cobalt and manganese doping (Bi0.95Co0.05Fe0.95Mn0.05O3 or BCoFMO) were both synthesized as nanocrystalline powders by the sol–gel autocombustion technique. X-ray diffraction examination of the powders indicates a rhombohedral distortion in the perovskite phase in both samples. The calcined powders were examined for their microstructure and elemental composition with high resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDAX), respectively. Scanning electron microscopy (SEM) was used to examine the microstructures of sintered BMFO and BCoFMO specimens at room temperature. Dielectric characteristics were studied at various frequencies and temperatures and found to follow space charge polarization. At ambient temperature, a vibrating sample magnetometer was used to analyse the materials' magnetic behaviour (M–H loops). Saturation magnetization is significantly increased with increased coercivity in the BCoFMO sample compared to the other sample. Improved structural, dielectric, and magnetic values in these doped systems, however, suggest they'd be an excellent fit for spintronic, multifunctional memories, sensors, and actuators. [ABSTRACT FROM AUTHOR]

Porous cerium oxide (ceria) nanoparticles were prepared with and without manganese (Mn) by using the flash combustion technique. Samples with different loadings (Ce/Mn ratio ranged from 100 to 10) were prepared by using a one-step process and water only as a solvent. Moreover, citric acid was utilized as a fuel in an aqueous medium, and the overall synthesis mixture was dried at 100 °C overnight and then calcinated at 550 °C for 3 h. The obtained final solid product was characterized by inductively coupled plasma (ICP), X-ray powder diffraction (XRD), diffuse reflectance ultraviolet-visible spectroscopy (DR-UV-Vis), and scanning electron microscopy (SEM), which was coupled with Energy Dispersive X-Ray Analysis (EDX), high resolution transmission electron microscopy (HR-TEM), and photoluminescence (PL) analysis. The characterization data showed that Mn ions were totally incorporated into the framework of ceria up to the applied loading. Under visible light illumination, the photocatalytic activity of the prepared samples was tested in the decolorization reaction of methyl green (MG) dye (wavelength greater than 425 nm). The results showed that increasing Mn content improved the photocatalytic activity of ceria. The sample with a Ce/Mn ratio of 10 performed 1.8 times better than bare porous ceria. Finally, the reusability of the best-performing sample was investigated in four consecutive runs without treatment, and slight deactivation was monitored after the fourth run. [ABSTRACT FROM AUTHOR]

Poly(vinyl chloride) (PVC) is one of the most used polymers, but the mechanical and esthetic properties can deteriorate for use outdoors because of ultraviolet (UV) light or heat. The addition of stabilizers is indispensable method for improving the stability of PVC. In this work, a facile synthetic method of CeO2 quantum dots (QDs) was used, for achieving the best dispersion and improvement of anti-UV properties, the surface of CeO2 QDs was modified by ethyl 3,4-dihydroxybenzoate (EDHB), which was dispersed within the PVC matrix using the casting method to investigate the anti-UV and thermal properties. X-ray powder diffraction spectra (XRD), infrared spectroscopy (FT-IR), high resolution transmission electron microscopy (HRTEM), UV spectrophotometry and thermogravimetric analysis (TGA) were applied to characterize the structures, morphologies, and properties. The results highlighted that EDHB/CeO2 can help reduce damages of PVC upon exposure to ultraviolet (UV) light and heat. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms that connect heat and electron transport with crystal structures and defect chemistry is fundamental to develop materials with thermoelectric properties. In this work, we synthesized a series of self‐doped compounds Cu2+xMn1−xGeS4 through Cu for Mn substitution. Using a combination of powder X‐ray diffraction, high resolution transmission electron microscopy and precession‐assisted electron diffraction tomography, we evidence that the materials are composed of interconnected enargite‐ and stannite‐type structures, via the formation of nanodomains with a high density of coherent interfaces. By combining experiments with ab initio electron and phonon calculations, we discuss the structure–thermoelectric properties relationships and clarify the interesting crystal chemistry in this system. We demonstrate that excess Cu+ substituted for Mn2+ dopes holes into the top of the valence band, leading to a remarkable enhancement of the power factor and figure of merit ZT. [ABSTRACT FROM AUTHOR]

Diagnosis and monitoring of glucose level in human blood has become a prime necessity to avoid health risk and to cater this, a sensor's performance with wide linearity range and high sensitivity is required. This work reports the use of ternary composite viz. MG–Cu2O (rGO supported MXene sheet with Cu2O) for non-enzymatic sensing of glucose. It has been prepared by co-precipitation method and characterized with X-ray powder diffraction, Ultraviolet–visible absorption spectroscopy (UV–Vis), Raman spectroscopy, Field emission scanning electron microscopy, High resolution transmission electron microscopy and Selected area diffraction. These analyses show a cubic structure with spherical shaped Cu2O grown on the MG sheet. Further, the electrocatalytic activity was carried out with MG–Cu2O sensing element by cyclic voltammetry and chronoamperometry technique and compared with M–Cu2O (MXene with Cu2O) composite without graphene oxide. Of these, MG–Cu2O composite was having the high defect density with lower crystalline size of Cu2O, which might enhance the conductivity thereby increasing the electrocatalytic activity towards the oxidation of glucose as compared to M–Cu2O. The prepared MG–Cu2O composite shows a sensitivity of 126.6 µAmM−1 cm−2 with a wide linear range of 0.01to 30 mM, good selectivity, good stability over 30 days and shows a low Relative Standard Deviation (RSD) of 1.7% value towards the sensing of glucose level in human serum. Thus, the aforementioned finding indicates that the prepared sensing electrode is a well suitable candidate for the sensing of glucose level for real time applications. [ABSTRACT FROM AUTHOR]

Controlling the reaction kinetics during the nucleation/growth of cupric oxide (CuO) nanostructures is very critical in order to achieve a specific and well-defined morphology. For this purpose, we have slowed down the reaction speed using a mixed solvent concept and successfully obtained a chain-like morphology of CuO nanostructures using hydrothermal method. The CuO chain-like morphology was synthesized using a 1:1 (v/v) ratio of ethylene glycol and water. The morphology and crystalline features of CuO were studied by scanning electron microscopy (SEM) and powder X-ray diffraction techniques. The high resolution transmission electron microscopy revealed 5 nm crystallite size for the CuO material prepared in the mixed solvents. The obtained results have shown that the prepared CuO chains had a monocline phase, containing only Cu and O as main elements as confirmed by energy dispersive spectroscopy. This unique morphology obtained from mixed solvent process has provided a better surface for the loading of urease enzyme, thus it enabled the development of sensitive and selective urea biosensor in phosphate buffer solution of pH 7.4. The physical adsorption method was used to immobilize urease enzyme onto the nano surface of CuO. The fabricated biosensor based on urease/CuO chains has shown a dynamic linear range from 0.0005 to15 mM with a low limit of detection 0.0001 mM. Additionally, a fast response time aroudn1s, h high selectivity, stability, repeatability, storage time, and reproducibility were observed. The effect of pH and temperature on the potentiometric signal of the developed biosensor was also examined. Importantly, the practical aspects of the fabricated urea biosensor were probed and the obtained percent recovery results revealed an outstanding performance. The strategy of using mixed solvent with equal volume ratio would be useful for the preparation of other metal oxides with improved catalytic properties for a wide range of clinical, biomedical and other related applications. [ABSTRACT FROM AUTHOR]

Low activation isotopic boron (11B) based magnesium diboride (Mg11B 2) superconductors doped with biomass-derived activated carbon were synthesized using 11B and magnesium powder via solid-state reaction. The effect of carbon doping on the lattice structure and superconducting properties of Mg11B 2 bulks were evaluated using X-ray powder diffraction, high resolution transmission electron microscopy, scanning electron microscopy and magnetization measurements. Precise refinement of structural parameters indicates successful substitution of carbon in Mg11B 2 bulks. The critical current density (J c) of carbon doped Mg11B 2 synthesized at 650 °C was enhanced more than two times compared with the pure Mg11B 2 bulk. Similar improvement was observed for the Mg11B 2 bulks heat-treated at 800 °C. This enhancement is due to successful substitution of biomass-derived carbon with high surface area into Mg11B 2 lattice. The flux pinning mechanism of pure and doped Mg11B 2 bulks were investigated using the Dew-Hughes model. This study provides information regarding enhancement of the J c of low activation Mg11B 2 superconductors suitable for next-generation fusion magnets. [ABSTRACT FROM AUTHOR]

The present report presents a green method for the rapid biogenic synthesis of nanoparticles that offers several advantages over the current chemical and physical procedures. It is easy and fast, eco-friendly, and does not involve any precious elements, hazardous chemicals, or harmful solvents. The synthesized ZnO nanoparticles were characterized using different techniques, such as UV-Visible spectroscopy. The surface plasmon resonance confirmed the formation of ZnO nanoparticles at 344 nm, using UV-Visible spectroscopy. The leaf extract acts as a source of phytochemicals and is primarily used for the reduction and then the formation of stable ZnO nanoparticles by the characteristic functional groups of the extract; the synthesized ZnO nanoparticles were identified using FTIR spectroscopy. The crystalline nature of ZnO-NPs was confirmed via powder X-ray diffraction (XRD). Size and morphology were measured via high resolution transmission electron microscopy (HR-TEM) analysis. The stability of the nanoparticles is established using dynamic light scattering (DLS) and thermogravimetric analysis (TGA). The synthesized ZnO nanoparticles have been found to be a good and efficient catalyst for the synthesis of novel 1,2-dihydro quinazoline derivatives under the green method via a one-pot reaction of 2-amino benzophenone, 1,3-diphenyl-1H-pyrazole carbaldehydes, and ammonium acetate. The synthesized compounds (4a–o) were characterized by the 1H NMR, 13C NMR, and HRMS spectra and were further validated for free-radical scavenging activity. The synthesized ZnO nanoparticles exhibited good antioxidant activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • SnS and SnS 2 are synthesized in the form of quantum dots from aqueous solutions. • Syntheses are conducted under room conditions thanks to application of ultrasound. • Influence of sonication time on QDs properties is investigated. • SnS and SnS 2 QDs were utilized as photo- and (for the first time) sonocatalysts. • The greatest color removal was observed in the case of SnS QDs sonocatalyst (85.2%) Our study reports the ultrasound-assisted synthesis of SnS and SnS 2 in the form of nanoparticles using aqueous solutions of respective tin chloride and thioacetamide varying sonication time. The presence of both compounds is confirmed by powder X-ray diffraction, energy-dispersive X-ray spectroscopy, as well as Raman and FT-IR spectroscopic techniques. The existence of nanoparticles is proven by powder X-ray diffraction investigation and by high resolution transmission electron microscopy observations. The size of nanocrystallites are in the range of 3–8 nm and 30 50 nm for SnS, and 1.5–10 nm for SnS 2. X-ray photoelectron spectroscopy measurements, used to investigate the chemical state of tin and sulphur atoms on the surface of nanoparticles, reveal that they are typically covered with tin on the same oxidation degree as respective bulk compound. Values of optical bandgaps of synthesized nanoparticles, according to the Tauc method, were 2.31, 1.47 and 1.05 eV for SnS (60, 90 and 120 min long synthesis, respectively), and 2.81, 2.78 and 2.70 eV for SnS 2 (60, 90 and 120 min long synthesis, respectively). Obtained nanoparticles were utilized as photo- and sonocatalysts in the process of degradation of model azo-dye molecules by UV-C light or ultrasound. Quantum dots of SnS 2 obtained under sonication lasting 120 min were the best photocatalyst (66.9 % color removal), while quantum dots of SnS obtained under similar sonication time were the best sonocatalyst (85.2 % color removal). [ABSTRACT FROM AUTHOR]

Herein we report a facile approach for the preparation of a magnetically separable Fe3O4@poly(m‐phenylenediamine)@Cu2O nanocatalyst and its catalytic efficiency in the synthesis of 5‐phenyl‐[1,2,3]triazolo[1,5‐c]quinazolines from (E)‐1‐bromo‐2‐(2‐nitrovinyl)benzenes, aldehydes, and sodium azide under mild reaction condition is described. The morphology, chemical composition, interior structure and magnetic properties of the Fe3O4@PmPDs@Cu2O nanocomposites were studied using powder X‐ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, energy dispersive X‐ray spectroscopy, X‐ray photoelectron microscopy, vibrating sample magnetometer and nitrogen adsorption‐desorption technique. The as‐prepared Fe3O4@PmPDs@Cu2O nanocatalyst was simply recovered using external magnet and reused up to successive six runs with no obvious loss in its catalytic efficiency and structural integrity (confirmed by powder X‐ray diffraction and transmission electron microscopy of recycled nanocatalyst) along with low leaching of copper (2.32 ppm) and iron (0.008 ppm) ions. The present protocol has a broad substrate scope with high yield in shorter reaction time and it does not require any additive or base. Overall, it has better green chemistry metrices like low E‐factor (0.93), process mass intensity (1.93), high reaction mass efficiency (51.9 %) and carbon efficiency (95 %). [ABSTRACT FROM AUTHOR]

The persistence of active pharmaceutical ingredients in water bodies has lead to detrimental impacts on public health as well as deteriorated aquatic resources at breakneck pace. To address this, highly fluorescent chitosan capped ZnS QDs (CZS QDs) were integrated with nickel ferrite nanoparticles (NF NPs) through ultrasonic assisted method to yield a series of magnetically responsive CZS-xNF nanohybrids (x = 5, 10, 15 and 20 wt% of NF). The successful fabrication of nanohybrids were affirmed through various techniques such as Fourier transform infra-red spectroscopy (FT-IR), powder X-ray diffraction (XRD), X-ray photoelectron microscopy (XPS), high resolution transmission electron microscopy (HRTEM), vibrating sample magnetometer (VSM) and diffused reflectance spectroscopy (DRS). The dual applicability of CZS-xNF nanohybrid was witnessed for the detection of pharmaceutical waste by fluorescence sensing and their concomitant annihilation via visible light driven photodegradation reactions. The developed nanohybrid showed exceptional selectivity towards tetracycline antibiotics, with ultra-low limit of detection of 0.53 μM for tetracycline (TC) and 0.30 μM for minocycline (MC), respectively. The fluorescent sensor was also analysed for trace level detection of tetracyclines in real water samples that showed satisfactory recoveries of 90–106%, depicting practical applicability of sensor. Additionally, the excellent photocatalytic features of synthesized nanohybrid prompted their use in photodegradation of TC and MC and a superior photocatalytic performance was achieved in comparison to CZS QDs. The enhanced photocatalytic performance of CZS-xNF nanohybrid can be attributed to type-I charge transfer mechanism, which resulted in efficient charge separation and reduced photo-induced recombination rate of charge carriers. The nanohybrids were recyclable up to four cycles after being utilized in sensing and photocatalysis, thus offering a promising strategy for environmental remediation through synchronized sensing and extirpation of pharmaceutical waste. The multifunctional magnetically retrievable CZS-xNF nanohybrids (x = 5, 10, 15 and 20 wt% of NF NPs) were designed by integrating highly fluorescent chitosan capped ZnS QDs (CZS QDs) and magnetic NiFe 2 O 4 nanoparticles (NF NPs) for detection and photocatalytic removal of pharmaceutical drugs, tetracycline and minocycline. [Display omitted] • Fabrication of photostable and biocompatible CZS-xNF nanohybrid using sonication method. • Uniform anchoring of CZS QDs onto the surface of NF NPs in CZS-xNF nanohybrid. • Ultralow level sensing and annihilation of pharmaceutical drugs, tetracycline and minocycline. • Sensitive and specific detection of tetracycline and minocycline in real water samples. • Excellent recyclability of CZS-10NF upto four sensing and photocatalytic cycles. [ABSTRACT FROM AUTHOR]

Titanium dioxide (TiO 2), neodymium (Nd3+) doped TiO 2 with the doping levels of 0.3% and 0.5% were synthesised by hydrothermal method and were characterized by powder X-ray diffraction (XRD), UV–vis diffused reflectance spectroscopy (DRS), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Ultraviolet X-ray photoelectron spectroscopy (UPS) and high resolution transmission electron microscopy (HRTEM). Doping of Nd3+ ions have been created new surface energy states below the conduction band of TiO 2 which mediate the photoinjected electrons through TiO 2 network to external load without any impediment. The Fermilevel (E f) of TiO 2 was shifted to downward direction upon Nd3+ ion doping confirmed from UPS analysis. An enhanced photoconversion efficiency (PCE) of 10.7% was achieved for the device fabricated using 0.3% Nd3+ ion doped TiO 2 which is higher than that of the device with undoped TiO 2 (10.1%). The noticeable increment in the PCE was due to the reduced charge recombination, longer electron lifetime and improved charge injection form LUMO of the N719 dye to the CB of TiO 2. [Display omitted] • Doping of Nd3+ in TiO 2 created new surface states that mediate the photoinjected electrons without any impediment. • The Fermilevel (E f) of TiO 2 was shifted to a downward direction upon Nd3+ ion doping confirmed from UPS analysis. • Enhanced photoconversion efficiency of 10.7% was achieved for the device fabricated using 0.3% Nd3+ ion-doped TiO 2. [ABSTRACT FROM AUTHOR]

• Hard-soft SrFe 12 O 19 /(CoEu 0.02 Fe 1.98 O 4) x nanofiber composites were prepared via electrospinning technique. • XRD, SEM and TEM analyses revealed the coexistence of hard and soft phases. • The magnitudes of optical bandgap E g are in the range of 1.56–1.77 eV. • The degree of exchange-coupling between hard and soft phases is well achieved. SrFe 12 O 19 (SFO) nanofibers (NFs), CoEu 0.02 Fe 1.98 O 4 (CEFO) NFs, and hard-soft (H/S) SrFe 12 O 19 (SFO)/(CoEu 0.02 Fe 1.98 O 4) x (CEFO) (x = 1.0, 1.5, 2.0, 2.5) nanofiber composites (NFCs) were produced via electrospinning approach. The X-ray powder diffraction (XRD) patterns for the studied compositions confirmed the coexistence of characteristics peaks of both phases (Sr-M-type hexaferrite and cubic spinel ferrite) without any impurity. The lattice parameters 'a′ and 'c′ for hexagonal SFO and 'a′ for CEFO NFs are fluctuating with increasing the ratio of CEFO NFs. The surface of nanofibers showed fibers having some roughness and bumps. They are consisted of hexagonal particles belong to SFO mixed and fine cubic CEFO NFs. These observations were confirmed by SEM (Scanning electron microscopy) along with EDX (Energy dispersive X-ray) and HR-TEM (High resolution transmission electron microscopy). The fibers showed a non-uniform cross-section with diameter between 33 and 95 nm. Diffuse reflectance spectroscopic (DRS) investigations were performed on SrFe 12 O 19 NFs, on soft CoEu 0.02 Fe 1.98 O 4 NFs, and on H/S (SFO)/(CEFO) (x = 1.0, 1.5, 2.0, 2.5) NFCs. Tauc method provided the estimation of optical bandgap (E g) of each sample. The magnitudes for E g are in the range of 1.56–1.77 eV. The magnetic responses of all samples in external applied magnetic field (M-H) were recorded at ambient temperature (T = 300 K) and low temperature (T = 10 K). Diverse produced nanofiber composites do not display no kinks in the measured M-H curves at both temperatures. Moreover, a single intense peak was clearly observed in the curves of dM/dH vs. H. These results reflected that the degree of exchange-coupling between hard and soft phases is well achieved via the employment of the electrospinning technique. At ambient temperature, it was observed that the magnetization is improving while the coercivity is diminishing with the increase in H/S ratio. On the contrary, at T = 10 K, the rise of CoEu 0.02 Fe 1.98 O 4 content within diverse H/S NFCs provokes a slight decline in magnetization and a great enlargement in coercivity. The plausible reasons for such tendencies were discussed. [ABSTRACT FROM AUTHOR]

This study features structural and photometric aspects of a down-converted green emanating erbium (Er3+) activated nanophosphor synthesized via a versatile and environmentally benign urea aided solution combustion procedure. The powder X-ray diffraction pattern (PXRD) of optimal sample SrGd 1.96 Er 0.04 Al 2 O 7 studied qualitatively by employing the Rietveld refinement practice, disclosed the tetragonal crystal phase with space group 14/mmm (139), consisting grains of size 50.03 nm. Surface morphology and grain size of nanopowders were well investigated by electron microscopy practices like scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). SEM micrograph gave clear insight that Er3+ doped nanophosphors possess slightly agglomerated particles with pores, voids and cracks due to high pressure breakout of gases while combustion synthesis. TEM and SEM images revealed the size of nanoparticles in the ambit of 40–60 nm which was in coherence with that obtained from the scherrer's equation, while the inter-fringes distance corresponding to diffraction plane (116) was calculated to be 0.27 nm from the HRTEM image. The desired nanophosphor showed brilliant green emission with an intense peak at 551 nm attributed to 4S 3/2 → 4I 15/2 transition of Er3+ ions, as analyzed through photoluminescent (PL) emission spectra monitored via near ultraviolet excitation wavelength (381 nm) with an optimal doping concentration of 2.0 mol%. Advanced photometric features like CIE color coordinates (0.3017, 0.6043), CCT (6032K), and color purity (76.52%) confirmed their green glow and are found to be in harmony with standard green emission. The study offers a luminous cool green emanating component for the fabrication of WLEDs and advanced optoelectronic appliances. [Display omitted] • SrGd 2 Al 2 O 7 :Er3+ nanophosphors were prepared via combustion procedure. • Absolute crystal phase was analyzed using XRD assisted Rietveld Refinement technique. • The new down-converted nanophosphors exhibit excellent green luminescence. • CIE chromaticity co-ordinates, CCT and color purity were inspected thoroughly. • Potential candidate for cool WLEDs, lasers and optical sensors. [ABSTRACT FROM AUTHOR]

• The variables of temperature, pressure and crystal size were examined separately. • The lattice parameters in HT-XRD are affected by both temperature and size effects. • The lattice parameter of Y 2 O 3 in MgO is higher than pure Y 2 O 3 according to HT-XRD. • A non-monotonic lattice variation (NMLV) in Y 2 O 3 due to the nano-effect was shown. • The NMLV was modeled combining the surface tension effect and the Madelung model. Yttrium oxide (Y 2 O 3) is a ceramic material in use in various fields such as catalysis, thermal barrier coatings, dental ceramics, solid-state lasers, solid oxide fuel cells and etc. In nanoscale metal oxides, unlike metals, the dependence of the lattice parameter on the crystal size is in dispute. Y 2 O 3 and 5 vol% Y 2 O 3 in MgO powders were synthesized via the sol-gel technique. The latter was made in order to produce Y 2 O 3 inclusions in MgO, allowing for the study of differences resulting from crystal size with inhibited thermal growth. However, the lattice parameters of the C-type Y 2 O 3 were significantly lower than expected due to misfit high compression stress. High-temperature X-ray diffraction (HT-XRD) was used in order to investigate in situ crystal structure and microstructure variations of Y 2 O 3 imbedded in MgO as formed at high temperatures free of misfit strain, comparing with in situ study of pure Y 2 O 3 formation at the same temperature range. It was found that nanocrystalline C-type Y 2 O 3 was formed at a temperature range of 873–1163 K. Lattice parameters and crystal size were evaluated by using Rietveld refinement and high resolution scanning electron microscopy (HR-SEM). The relative lattice parameter changes as a function of crystal size were obtained by analyzing the in situ HT-XRD data from 873 to 1573 K. Those results along with those obtained at room temperature showed a non-monotonic trend: lattice contraction versus decreasing crystal size at the range of 60–45 nm crystal size and lattice expansion versus decreasing crystal size for smaller crystals (approximately 0.11%). The non-monotonic lattice variation was modeled by assuming two effects acting simultaneously as a function of crystal size: lattice contraction due to hydrostatic pressure caused by the surface tension and Madelung model predicting lattice expansion due to weakening of bonding force in small ionic crystals. The calculated theoretical lattice parameters values which were obtained by using this model were compared to the experimental results yielding a better understanding of the lattice variations in nano-Y 2 O 3. [ABSTRACT FROM AUTHOR]

In this work, the photocatalytic hydrogen evolution from ammonia borane under near-infrared laser irradiation at ambient temperature was demonstrated by using the novel core-shell upconversion-semiconductor hybrid nanostructures (NaGdF4:Yb3+/Er3+@NaGdF4@Cu2O). The particles were successfully synthesized in a final concentration of 10 mg/mL. The particles were characterized via high resolution transmission electron microscopy (HRTEM), photoluminescence, energy dispersive X-ray analysis (EDAX), and powder X-ray diffraction. The near-infrared-driven photocatalytic activities of such hybrid nanoparticles are remarkably higher than that with bare upconversion nanoparticles (UCNPs) under the same irradiation. The upconverted photoluminescence of UCNPs efficiently reabsorbed by Cu2O promotes the charge separation in the semiconducting shell, and facilitates the formation of photoinduced electrons and hydroxyl radicals generated via the reaction between H2O and holes. Both serve as reactive species on the dissociation of the weak B-N bond in an aqueous medium, to produce hydrogen under near-infrared excitation, resulting in enhanced photocatalytic activities. The photocatalyst of NaGdF4:Yb3+/Er3+@NaGdF4@Cu2O (UCNPs@Cu2O) suffered no loss of efficacy after several cycles. This work sheds light on the rational design of near-infrared-activated photocatalysts, and can be used as a proof-of-concept for on-board hydrogen generation from ammonia borane under near-infrared illumination, with the aim of green energy suppliers. [ABSTRACT FROM AUTHOR]

Here, CoFe 2 O 4 was loaded on Bi 2 O 3 via sonochemical technique to enhance the photocatalytic performance of Bi 2 O 3. The coexistence and crystallinity of CoFe 2 O 4 and Bi 2 O 3 was verified using X-ray powder diffraction (XRD). High resolution transmission electron microscopy (HRTEM) depicts attachment of CoFe 2 O 4 nanospheres on sheet-like Bi 2 O 3. Chemical states were examined using XPS. Visible light harvesting is facilitated by the narrow band gap (2.7 eV) of the nanocomposites (NCs). Reduced intensity in photoluminescence spectra indicates improved lifetime of electron/hole (e-/h+) pairs. The photocatalytic rate was boosted 3 – 3.75 times in NCs compared to pristine nanoparticles (NPs). The coupling of NPs resulted in type I heterojunction formation at the interface. The H 2 O was oxidized by h+ present in the valence band (VB) of CoFe 2 O 4 as it has higher positive potential and converted into hydroxyl radical (·OH). High resistance to photo-corrosion and stable performance of magnetically removed NCs was observed. The growth of Escherichia coli and Bacillus subtilis was inhibited upon NCs exposure. The operational simplicity and potential visible-light harvesting promote the usage of CoFe 2 O 4 -Bi 2 O 3 NCs in various sectors such as environmental remediation and antimicrobial application. Schematic representation of the photocatalytic mechanism of CoFe 2 O 4 -Bi 2 O 3 NCs [Display omitted] • CoFe 2 O 4 nanospheres loaded Bi 2 O 3 nanosheet was constructed. • Sonochemical assisted co-precipitation technique was adopted for synthesis. • The photocatalytic activity of NCs was enhanced by 3–3.75 times than individual NPs. • The OH· play major role in dye degradation. • The particles exhibited excellent antibacterial activity. [ABSTRACT FROM AUTHOR]