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This research discloses a single step, facile, cost-effective, and eco-friendly fabrication of gold nanoparticles (AuNPs) using the aqueous extract of common reed (Phragmites australis) leaf. Various techniques were employed to characterize the resultant AuNPs such as UV–Vis spectroscopy, high resolution transmission electron microscopy (HRTEM) mapping, fourier transform infrared (FT-IR), Zeta potential, X-ray diffraction (XRD), Energy Dispersive X-ray spectroscopy (EDX), and X-ray Photoelectron Spectroscopy (XPS) to confirm the bioformation of AuNPs. The results showed the formation of violet-colored, mainly spherical shaped AuNPs with about 18 nm diameter. The XRD results proved the crystalline structure of AuNPs. Furthermore, P. australis-AuNPs exhibited notable anticancer efficacy with an IC50 equals 129 μg/mL, good quenching for DPPH free radical with a scavenging percentage equals 10.26% and a superior photocatalytic activity as they completely removed methylene blue in just 1 min. The current study also provides an open option for the environmental management of the unwanted biomass of common reed. [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]

[Display omitted] • First report on C-dots derived from beetroot and Fabrication of 0D/0D C-dots@CdS heterostructured photocatalysts. • C-dots@CdS showed superior activity with H 2 evolution rates of 1582 µmolg−1 than the pristine CdS (849 µmolg−1). • Achieved 97.3 % degradation efficiency of CV dye under visible light for C-dots@CdS. • The presence of C-dots in heterojunction increases the charge carrier separation leading to highest photocatalytic activity. Carbon dots (C-dots) developed from beetroot is used for the rational design of cadmium sulphide based heterojunction photocatalysts (C-dots@CdS) using hydrothermal technique. The crystal structure, phase, morphology and optical characteristics of the synthesised materials are determined using X-ray diffraction (XRD), High resolution transmission electron microscopy (HR-TEM), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV–Visible diffuse reflectance spectroscopy (UV-DRS), photoluminescence spectroscopy (PL spectroscopy), BET adsorption, X-ray photoelectron spectroscopy (XPS) and electrochemical studies. Using C-dots@CdS catalytic system, a superior photocatalytic activity relative to the undecorated CdS is observed. Among the C-dots@CdS samples, the CdS loaded with 6 wt% of C-dots exhibited enhanced hydrogen evolution rate compared with other samples considered for the study. CdS nanospheres modified with C-dots (6 wt%) resulted in the photocatalytic hydrogen evolution rate of 1582 µmolg−1 against 849 µmolg−1 evolution rate obtained for CdS nanospheres within 3 h. In spite of being 0D/0D type nano-heteroarchitecture, C-dots@CdS system obtained an apparent quantum yield of 6.37 % for the catalytic dosage of 20 mg under the irradiation of visible light. CdS in the C-dots@CdS system serves as the light harvester while C-dots with discernible edges can maintain the continuous supply of photo-excited charge carriers and hence can reduce the charge-carrier recombination. Further, the photodegradation of crystal violet dye using the optimised dosage of C-dots@CdS-6 exhibited an efficiency of 97.3 % in 120 min of visible light irradiation under neutral conditions. The detailed kinetic study reveals that the mechanism of photodegradation of crystal violet dye using C-dots@CdS system can be described using pseudo-second-order kinetics. The presence of oxygen rich hydrophilic surface functionalities of C-dots, the formation of near-surface heterojunction and the suitable band structure of C-dots@CdS system leading to the optimum charge carrier separation kinetics can be attributed to the enhanced photocatalytic performance. This work offers a promising strategy to develop bio-derived C-dots based heterojunction photocatalyst to address the burgeoning energy and environmental demands. [ABSTRACT FROM AUTHOR]

The carbon-based composite materials prepared through green synthetic approach are attracting greater interest in electrochemical applications due to their sustainable nature. Herein, we developed Fe 2 O 3 and Fe 2 O 3 @CNT composite materials via a green mechanochemical one-pot method. The as prepared composite materials were characterized by X-ray diffraction (XRD), energy dispersive X-Ray spectroscopy (EDS), field emission scanning microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), and X-ray photoelectron spectroscopy (XPS), respectively. Incorporating Fe 2 O 3 nanoparticles on CNT surface tunes its electronic structure as well increases active sites and thus enhance the oxygen evolution reaction (OER) performance. As a result, the fabricated Fe 2 O 3 @CNT is a highly effective and balanced electrocatalyst that delivers superior current density (j = 10 mA cm−2) at low overpotential (η = 270 mV) for OER compared with pristine Fe 2 O 3 (η = 290 mV) in 1 M KOH. Further, Fe 2 O 3 @CNT electrocatalyst shows high long-term durability in 1 M KOH for 100 h, fulfilling all the advantageous viable standards for OER. [ABSTRACT FROM AUTHOR]

Background: The emergence of antibiotic resistance and the continuing evolution of resistance even to newer drugs have always been a global challenge. In the pursuit of innovative solutions, there is growing interest in using nanomaterials with antibacterial potentials to combat this menace. Objectives: In this study, plant extract cocktail-mediated silver nanoparticles (PAgNPs) was used to stimulate the antibacterial effect of ampicillin (AMP) against multidrug-resistant (MDR) bacterial pathogens. Methods: The agar well diffusion technique was used to investigate the potentials of PAgNPs in activating the antibacterial activity of AMP in MDR bacteria, including Escherichia coli, Klebsiella pnuemoniae, Micrococcus luteus, and Clostridium difficile. Plant extract cocktail-mediated silver nanoparticles were synthesized by reacting 9 mL of 1 mM of silver nitrate with 0.5 mL each of Citrus limon juice and aqueous Newbouldia laevis extract under bright sunlight for 10 minutes. Plant extract cocktail-mediated silver nanoparticles were characterized using UV-visible spectroscopy (UV-Vis) and higher resolution transmission electron microscopy (HRTEM) with energy dispersive x-ray spectroscopy (EDS). Results: Plant extract cocktail-mediated silver nanoparticles colloidal solution was reddish-brown with a 441-nm surface plasmon resonance (SPR) absorption peak. The HRTEM micrograph showed the varied shaped silver nanoparticles (AgNPs) with the average size of 23.49±10.49 nm. Similarly, EDS showed a strong typicalmetallic silver nanocrystallites absorption peak at 3.0 keV. The PAgNPs activate the AMP activity in MDR E. coli, M. luteus, K. pnuemoniae, and C. difficile. Conclusions: The present findings suggest that PAgNPs can be considered a suitable candidate for developing novel antibacterial drugs to combat the growing threat of antibiotic resistance. [ABSTRACT FROM AUTHOR]

Flexural behavior of red deer's (Cervus Elaphus) antler is managed by not only orientation of osteons but also age, number density of fully fledged Cross-Linking Fibers (CLFs) and mineralization. Although crack propagation is affected by all these factors, a possible role of CLFs during the deformation remains rather disguised. The aim of this study was to enlighten the effect of dimensions, micro skeleton and mineral content of CLFs on plastic deformation. Therefore, mechanical properties, microarchitecture and mineralization of fracture sites of deer antlers were investigated using three-point bending tests in 32 specimens followed by high resolution scanning electron microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). The bending tests show that maximum bending strength is in the range of 150–177 MPa, and elastic modulus approximates to 5–6 GPa. Furthermore, fracture toughness of the test specimens examined for all branching groups of antlers was 8–9 MPa · m 1 / 2 . Age and the number of branching albeit are main reasons for differentiating microarchitecture and varying mechanical properties. SEM analyses show that a hierarchical architecture from bottom to up exists, in which some feathers and nano-sized fibrils are attached to larger fibrils that brings CLFs altogether. Antlers of adolescent deers are supposed to have shorter and thinner cross-linking fibers than elder ones. Some feathered micro-fibrils were identified across the CLFs connecting osteons. The thickness (270.0–320.0 nm) and length (700 nm) of feathers were strictly proportional to the microfibrils' size (10.0 µm in length and 1.0 µm in thickness). Furthermore, weight percentages of minerals varies along the CLFs that taking root on osteons by a bundle of many smaller fibrils whereas Pb, Cd and Hg have the highest values at the tip of broken CLFs. Such high values of these brittle elements lead to cracked ligament bridging as well. [ABSTRACT FROM AUTHOR]

In this paper, the role of antimony (Sb) as a dopant in single-phase bulk Cu2ZnSnSe4 (CZTSe) has been studied. The sb-doped CZTSe bulk material has been synthesized via facile mechanical dry ball milling method. The structural characterization and phase formation were studied through X-ray diffraction (XRD) and Raman spectroscopy. Particle size and electron diffraction measurements were done using high resolution transmission electron microscopy and selected area electron diffraction. Field emission scanning electron microscope and energy dispersive X-ray spectroscopy analyses have been done to infer morphology and composition. Oxidation state of constituent elements in milled powder was studied by X-ray photoelectron spectroscopy analysis. The results of XRD and Raman results are suggestive that the dry milling is a reliable method for the synthesis of single-phase CZTSe. It is also possible to achieve doping with low concentrations of Sb during the milling process to obtain sb-doped bulk single-phase CZTSe. [ABSTRACT FROM AUTHOR]

High manganese steel is influenced by the combined effects of corrosion and wear during service under specific conditions, resulting in components with shortened service life. Under harsh service environments, newly developed Cr+N alloyed austenitic high manganese steel (Mn18Cr7C0.6N0.2 steel) as a new type of railway steel has shown promising results. Herein, the tribocorrosion behaviors of Mn18Cr7C0.6N0.2 and Mn13C1.1 steels in artificial acid rain were studied using electrochemical methods, field emission scanning electron microscope (FE-SEM), focused ion beam scanning electron microscopy (FIB-SEM), scanning transmission electron microscopemicroscopy energy dispersive X-ray spectroscopy (STEM-EDS), and high resolution transmission electron microscopy (HR-TEM). The results showed the formation of passive film and gradient-nanostructure on surfaces of both test steels during tribocorrosion. A dense and tightly adhering amorphous passive film was formed on Mn18Cr7C0.6N0.2 steel surface with a superior blocking effect toward invasive ions. The high strain resistance and plasticity of the Mn18Cr7C0.6N0.2 steel resulted in an intact gradient-nanostructure, suitable for obtaining high surface hardness and maintaining the toughness of the matrix, contribute to providing high wear resistance. The oxide film on the Mn13C1.1 steel surface comprised crystal α-FeOOH. Vortex cracks formed in its gradient structure due to strain localization. Meanwhile, the relatively poor corrosion protection ability and vortex cracks of its gradient-nanostructure prevented it from maintaining interface integrity of the gradient nanostructure, resulting in inferior tribocorrosion resistance. In artificial acid rain, the new type of Cr+N alloyed Mn18Cr7C0.6N0.2 steel exhibited higher tribocorrosion resistance than traditional high manganese steel, promising for use as an excellent wear-resistant material under corrosive environments. • An amorphous passive film formed on the surface of Cr+N alloyed high-Mn steel. • The gradient-nanostructure of Cr+N alloyed high-Mn steel maintained integrity. • Vortex cracks formed in the gradient-nanostructure of traditional high-Mn steel. • Gradient-nanostructure and passive film determined the tribocorrosion resistance. • The surface layer and passive film were fully observed by FIB and TEM. [ABSTRACT FROM AUTHOR]

Methyl orange (MO), which is known as a highly durable dye that is extremely toxic to humans and animals, has been processed by using various methods. In recent years, MO degradation through reduction in the presence of NaBH 4 (NB) and suitable nanocatalyst have garnered considerable interest. However, the nanosized particles of the catalyst make separation from the liquid solution more difficult and limit the practical application of this technique. Herein, copper nanoparticles (CuNPs) decorated on three-dimensional chitosan aerogel (CSA) were synthesized as a reusable composite for the catalytic degradation of MO by using a green method with durian (Durio zibethinus) shell (DS) extract as a reducing agent. The Cu/CSA composite's physicochemical properties were characterized by using X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscopy- energy dispersive X-ray spectroscopy (SEM-EDS), high resolution Transmission electron microscopy (HR-TEM), Brunauer-Emmett-Teller (BET) and Raman spectroscopy. These modern techniques elucidated the structure and formation of copper nanoparticles on the CSA surface. The copper nanocatalysts have an average particle size of 32.6 nm, specific surface area of 55.8 m2/g, pore size of 32 Å and pore area of 0.049 cm3/g. Through the investigation of catalyst activity, the conditions of MO reduction were optimised with the 1.0 Cu/CSA sample, catalyst dose of 0.5 g/L and a molar ratio of MO/NB of 1/200. The reaction reached over 94.3% efficiency after 10 min, correlating with a kinetic rate constant of 0.163 min−1. It is worth mentioning that the optimized catalyst can be conveniently synthesized and retrieved from the reaction solution in just 5 s using a vacuum filter. Furthermore, its effectiveness remains largely unaffected even after undergoing five cycles of reuse, thus demonstrating its exceptional durability and potential in environmental remediation. [Display omitted] • An alternative chitosan aerogel-based support for metal nanoparticles. • Nano-copper/chitosan aerogel (Cu/CSA): a benign reduction using durian shell extract. • Outstanding reactivity of Cu/CSA in the catalytic reduction of methyl orange. • High stability and proficient reusability of Cu/CSA during 5 consecutive cycles. [ABSTRACT FROM AUTHOR]

Copper indium disulfide (CuInS 2) single crystals are prepared by the chemical vapour transport technique and characterised by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FESEM), and high resolution transmission electron microscopy (HRTEM). The XRD outcome reveals tetragonal lattice structure. The EDS result confirms that the sample is near stoichiometry, while the FESEM and HRTEM micrographs show multilayered opaque crystals. The lattice fringe arrangement reveals d -spacing of 0.32 nm, which matches the d -spacing of primary peak (112) of XRD. Electrical resistivity value decreases as temperature varies from 303 K to 423 K, confirming the crystal is semiconducting. The negative signs in the Hall coefficient (−8.49 × 105 cm3·C−1) and Seebeck coefficient (−148 μV·K−1) confirm n-type nature. The maximum figure of merit (zT) is predicted as 3.99 × 10−4 at 423 K. It suggests that CuInS 2 has the prospective to be used in thermoelectric power generation. [Display omitted] • CuInS 2 single crystals synthesised by the CVT technique. • Study of transport properties of the single crystals. • The crystals are n-type semiconductors. • The synthesized crystals showed good thermoelectric figure of merit. [ABSTRACT FROM AUTHOR]

[Display omitted] • A multifunctional maca extract-coated CuO nanoparticles was prepared. • The prepared nanostructure had excellent antimicrobial and dopamine sensing performances. • High sensitive electrochemical and colorimetric CuO NPs biosensor sensing for dopamine. • High antimicrobial activity of CuO NPs against pathogenic microorganisms. Current trends and future innovative issues focus on the development of smart multifunctional bio-nanostructures. In this study, novel maca extract-coated CuO nanoparticles (MaE-CuO NPs) were prepared using a green and facile sonication method. Multifunctional MaE-CuO NPs were characterized by different techniques, such as Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), High Resolution Transmission Electron Microscopy (HRTEM), Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and Brunauer–Emmett–Teller (BET) techniques. According to the results, we proved that the sonosynthesized MaE-CuO NPs had a uniform spherical shape with an average diameter range of ∼ 10 nm, while the surface area was 344.645 m2/g. The preservative performance of the antimicrobial MaE-CuO NPs was investigated to evaluate the biological activity of the nanostructure against Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli), Candida albicans (C. albicans), and Aspergillus brasiliensis (A. brasiliensis). Furthermore, the MaE-CuO NPs-based non-enzymatic electrochemical and smartphone colorimetric biosensor detected dopamine in the concentration range from 0.625 to 5 µM with a high sensitivity of 667 µA μM−1cm−2 and a low limit of detection (LOD) value of 16.9 nM. Consequently, we proved that the obtained nanoformulations are promising antimicrobials agents and colorimetric/electrochemical dual-mode biosensors. [ABSTRACT FROM AUTHOR]

Carbon dots are quasi-spherical and zero dimensional nanomaterials with unique optical and electronic properties. In this work, a facile and sustainable strategy was employed to synthesise nitrogen doped carbon dots from Terminalia chebula via hydrothermal treatment with a quantum yield of 19.9%. The structural and optical properties of nitrogen doped carbon dots (N-CDs) were studied by UV–Visible absorption and fluorescence spectroscopy. The surface functional groups, average particle size and elemental analysis were assessed with the help of Fourier Transform Infra Red spectroscopy, High Resolution Transmission Electron Microscopy and Energy Dispersive X-ray analysis respectively. The N-CDs exhibited excitation dependent emission upon irradiation with UV light, pH stability over neutral range and excellent photostability. The average particle size of the synthesised N-CDs was found to be 3.56 nm. The fluorescence intensity of the N-CDs quenched linearly with increase in concentration of Fe3+ ions. The limit of detection (LOD) of N-CDs with Fe3+ ions was calculated to be 4.5 nM using Stern-Volmer plot. The fluorescence was restored by addition of EDTA to Fe3+ coordinated N-CD system. Further, the synthesised N-CDs interacted with ct-DNA through intercalative mode and the binding constant calculated using the Benesi Hildebrand plot was 1.78 × 108 mg/mL. The cytotoxicity of N-CDs was evaluated using MTT assay. The excellent biocompatible and less toxic nature of N-CDs was extrapolated to serve as fluorescent probes for imaging E.coli and SKMEL cells. From the results of this work, it is evident that the synthesised N-CDs can be used to develop efficient fluorescent metal sensors. The fluorescent property of N-CDs enables it to find extension as a potential curative drug, an efficient patterning agent and an effective biomarker to image biological cells causing no damage to normal cells. [Display omitted] • Highly fluorescent nitrogen doped carbon dots from Terminalia chebula with 19.9% quantum yield. • Excellent hydrophilic nature with heteroatom rich functional groups and fluorescence property. • Fluorescent probes for efficient "turn-on-off" sensors for Fe3+ ions with limit of detection 4.5 nM. • Intercalative interaction with ct-DNA with a binding constant of 1.78 × 108 (mg/mL). • Patterning agents and excellent fluorescent biomarkers to image SKMEL and E.coli cells. [ABSTRACT FROM AUTHOR]

This work describes the synthesis of Ag decorated CoO nanocomposites (NCs) supported on chitosan (CS-Ag/CoO NCs) for simple, low cost and rapid colorimetric detection of L -cysteine, and for the photocatalytic reduction of hexavalent chromium (Cr(VI)) ion. The NCs was characterized thoroughly by using UV–vis spectrophotometer, fourier transform-infrared spectroscopy (FT-IR), high resolution transmission electron microscopy (HR-TEM), thermogravimetric analysis (TGA), X-ray diffraction spectroscopy (XRD), energy dispersive x-ray spectroscopy (EDAX), and X-ray photoelectron spectroscopy (XPS). The NCs displayed high specificity, sensitivity and selectivity towards the L -cysteine detection and quantification from aqueous samples. The limit of detection of the prepared probe was 4.67 nM. The particle size of CS-Ag/CoO NCs was found to be 8.52 ± 0.13 nm. The CS-Ag/CoO NCs interaction with L -cysteine, interestingly causes the aggregation of NCs with increase in particle size to 956 ± 0.23 nm. The color change was observed from yellow to color less. An excellent linear correlation exists between the absorbance vs logarithmic concentration of L -cysteine (10 nM- 1 mM). Here, 250 mg/L of NCs reduced 100 mg/L of Cr(VI) to Cr(III) within 180 min. The kinetic data suggested that the NCs exhibited greater photocatalytic reduction efficiency than CoO and Ag/CoO. The paper-based test strips were developed and applied for the rapid colorimetric assay for the onsite monitoring of L -cysteine from real samples. The study demonstrated a specific detection of L -cysteine irrespective of the source of samples using CS-Ag/CoO NCs. Hence, the prepared NCs can be used as a colorimetric probe and provides a practical application for photocatalytic reduction of Cr(VI). The NCs also exhibitted excellent antimicrobial activity. [Display omitted] [ABSTRACT FROM AUTHOR]

Tunable white light-emitting Ca (2-x) Sb 2 O 7 :xDy3+ phosphors were synthesized via high temperature solid-state reaction method. The crystal structure, morphology, luminescence characteristics, and energy transfer mechanism of the phosphors were investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), high resolution transmission electron microscopy (HR-TEM), UV–Visible spectroscopy, photoluminescence (PL) spectroscopy, and Fluorescence lifetime analysis. The XRD, EDS, and TEM analysis confirmed the phase purity and orthorhombic weberite structure of the samples with an average particle size in the range of 0.2 to 0.3 ​μm. Under ultraviolet (UV) excitation of 330/351 ​nm, the prepared phosphors exhibit characteristic emission bands of Dy3+ ions along with the blue emission band of the host. The broad band peaking at 440 ​nm corresponds to Sb5+ to O2− transition of host and the peaks at 477, 575, and 670 ​nm originates from 4F 9/2 ​→ ​6H 15/2 , 4F 9/2 ​→ ​6H 13/2 and 4 F 9/2 ​→ ​6H 11/2 transitions of Dy3+ ions respectively. There exists efficient energy transfer from Ca 2 Sb 2 O 7 host to Dy3+ ions and the energy transfer efficiency increases with an increase in Dy3+ ion concentration. Using Dexter's theory, the mechanism of energy transfer was found to be dipole-quadrupole interaction and the energy transfer process is explained in detail. The decay lifetime of Dy3+ ions was estimated to be in the microsecond range. The critical distance for concentration quenching is determined to be 13.807 ​Å and the dominant mechanism is dipole-dipole interaction. The calculated Commission International de L'Eclairng (CIE) coordinates and correlated color temperature (CCT) values imply that the emission color can be tuned from blue (0.144, 0.097) to near-white (0.296, 0.292) in the cool CCT region. The results suggest that Dy3+ doped Ca 2 Sb 2 O 7 phosphor is a potential candidate for solid-state lighting and display fields. [Display omitted] • Ca (2-x) Sb 2 O 7 :xDy3+ phosphors with orthorhombic weberite structure were synthesized via solid-state reaction method. • Photoluminescence spectra exhibit characteristic emission bands of Dy3+ ions along with blue emission band of the host. • Efficient energy transfer exists between host and Dy3+ ions via electric dipole-quadrupole interaction. • The emission color of the phosphors can be tuned from blue (0.144, 0.097) to near-white (0.296, 0.292). • The decay lifetime of the Dy3+ ions were found to be in the microsecond range in Ca 2 Sb 2 O 7 host. [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 we present a simple method to fill multiwalled carbon nanotubes (MWCNT) with silver. This method involves stirring of MWCTs in AgNO 3 solution at room temperature in open air followed by heating in H 2 atmosphere at 250 °C for two hours. Process also leads to small coating of Ag on the surface. We confirmed the presence of crystalline silver in both coating and filling in hybrid MWCNTs by high resolution transmission electron microscopy, energy dispersive X-ray spectroscopy and electron diffraction. After silver coating and filling, bulk thermal diffusivity and thermal conductivity of Ag hybrid MWCNTs were increased by 242% and 255%, respectively. Furthermore, current-voltage measurements using tuna probe in atomic force microscopy showed higher number of charge carriers in the Ag hybrid nanotubes compared to pristine MWCNTs which resulted in up to 173% increase in their electrical conductivity. The Ag hybrid MWCNT based sensor also showed rapid and reversible sensing for I 2 vapors: bulk sensor film demonstrated sensing response of 45% in just ~60 s at room temperature. However, the sensor recovery was slower: after removal of I 2 vapors source, the recovery took 400 s and required heating at 100 °C in air. Response and recovery of sensor film was maintained after repeated cycles of exposure. Finally, the Ag hybrid MWCNTs film displayed high stability and selectivity for I 2 vapors. [Display omitted] • Synthesis of Ag filled MWCNTs using a simple method • Bulk thermal conductivity of Ag hybrid MWCTs is 255% more than of MWCNTs. • Addition of Ag increases the bulk electrical conductivity of MWCNTs by 173%. • More negative charge carriers in the Ag hybrid MWCNTs than pristine MWCNTs • Ag hybrid MWCNTs showed rapid and reversible sensing for I 2 vapors. [ABSTRACT FROM AUTHOR]

• Guanine as a heterogeneous and recyclable base in the synthesis of novel spirooxindole compounds. • Usage of magnetic support for catalyst and its easy separation from the reaction medium. • synthesis of some novel spirooxindole compounds and highly substituted dihydro-2-oxopyrroles in aqueous media. • Recyclability and reusability of the catalyst up to ten times. Guanine stabilized on the surface of silica-modified magnetic nanoparticles, by the propyl group as a linker, (Fe 3 O 4 @SiO 2 -n-(propyl)-guanine), was prepared, identified and used as a recyclable base in the synthesis of novel spirooxindole compounds and highly substituted dihydro-2-oxopyrroles in aqueous media. Fe 3 O 4 @SiO 2 -n-(propyl)-guanine was characterized via some spectroscopic and microscopic techniques such as Infrared spectroscopy (IR), X-ray diffraction spectroscopy (XRD), Energy dispersive X-ray spectroscopy (EDX), Vibrating sample magnetometry (VSM), Scanning electron microscopy (SEM), High resolution transmission electron microscopy (HR-TEM), Thermo-gravimetric analysis (TGA) and NMR-detected hydrogen/deuterium (H/D) exchange technique. The synthesized nanocomposite was employed as a new base catalyst for the synthesis of some novel spirooxindole compounds and highly substituted dihydro-2-oxopyrroles in aqueous media with good to excellent yields. This heterogeneous base catalyst could be recycled and reused up to ten times without appreciable loss of activity. [Display omitted] [ABSTRACT FROM AUTHOR]

This work investigates the degradation of the azo dye solochrome dark blue (SDB) by measurement of the photocatalytic, sonocatalytic and sonophotocatalytic activities, under low ultrasonic frequency (40 kHz) and UV-C (254 nm) light, using Mn-doped ZnS semiconductor quantum dots (Mn2+:ZnS Qds) as catalysts, prepared by a simple chemical precipitation procedure. In order to study the different morphological and optical crystal properties, various characterization techniques were used, such as high resolution transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, N2 adsorption-desorption at −196 °C and ultraviolet-visible spectroscopy. The average particle size of the semiconductor Qds was in the range of 3–4 nm. The optimal parameters affecting dye degradation, such as the catalyst loading, solution pH, time of irradiation, initial concentration of dye, dopant concentration, ultrasonic power and frequency effect were evaluated. The synthesized catalytic material exhibited a high activity for sonophotocatalytic degradation of SDB (89%), larger than that observed for sonocatalysis (69.7%) or photocatalysis (55.2%) alone, which was due to the improved electron-holes separation, formation of more reactive radicals and enhancement of the active surface area. Qds showed good stability and reusability after five repeated cycles. Finally, the degradation products were identified by liquid chromatography-mass spectrometry (LC-MS). [ABSTRACT FROM AUTHOR]