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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]

β-Bi 2 O 3 and Ni-incorporated β-Bi 2 O 3 nanoparticles with different Ni incorporating amounts (0, 2, and 4 at. wt. %) were successfully synthesized through a viable hydrothermal process. As-synthesized nanoparticles were analyzed by complementary analytical tools such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), UV–visible spectroscopy (UV–Vis), and photoluminescence spectroscopy (PL) for structural, microstructural, compositional, and spectral properties. The photocatalytic performance of synthesized nanoparticles was assessed by subjecting them to visible light irradiation and monitoring the decomposition of rhodamine-B dye. The findings demonstrated that the inclusion of Ni(4%) in β-Bi 2 O 3 nanoparticles significantly enhanced its photocatalytic activity compared to pristine β-Bi 2 O 3 which is desirable for environmental remediation. This improvement may be caused by increased generation of electron-hole (e−-h+) pairs, reduced recombination rate of these pairs, enhanced absorption of visible light, and a decreased band gap energy. To evaluate the specific capacitance characteristics of synthesized electrode materials, cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance analyses were conducted. The super capacitance activities of prepared electrode materials were observed in the order of Bi 2 O 3 < Ni(2%)-Bi 2 O 3 < Ni(4%)-Bi 2 O 3. Notably, Ni(4%)-Bi 2 O 3 nanocomposite exhibited higher supercapacitance, which can be attributed to the effective role of appropriate nickel incorporation in Bi 2 O 3. These results suggested that the incorporation of Ni(4%) into β-Bi 2 O 3 to form a nanocomposite showed greater capability as an effective electrode material for advanced energy storage devices, especially supercapacitors. Ni (0,2,4%) incorporated-Bi 2 O 3 nanoparticles were successfully synthesized and characterized through viable techniques. Ni (4%)- Bi 2 O 3 nanoparticles have shown enhanced visible light driven photocatalytic activity against organic dyes for environmental remediation. It also exhibited high supercapacitance desirable for high capacity electrode material employable in supercapacitors. [Display omitted] • Ag NPs-loaded brookite TiO 2 NWs supported on rGO sheets were produced hydrothermally. • Structure and morphology were evaluated by XRD, XPS and SEM/TEM. • Ag–TiO 2 /rGO nanohybrid exhibited an excellent light induced photocatalytic performance. • A suitable schematic mechanism was proposed for photocatalytic degradation of dye. • Ag–TiO 2 /rGO nanohybrid demonstrated fairly high electrochemical electrode material characteristics. [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]

Owing to the combination of good thermo-optical properties and inhomogeneously broadened fluorescence spectra suitable for ultrashort laser pulse generation, rare-earth doped solid solutions of sesquioxides (Y,Lu,Sc) 2 O 3 have attracted considerable interest in recent years. In this study, compositionally disordered Tm3+-doped YScO 3 transparent ceramic was fabricated using solid-state vacuum sintering of nanopowder produced using laser ablation of solid target in air flow. The as-synthesized powder consisted of weakly aggregated spherical particles having 20 nm diameter and a mostly monoclinic (space group C 2/ m) crystal structure, whose symmetry was transformed into cubic (space group Ia -3) by calcination at 1050 °C. From high resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray analysis (EDX), we observed a homogeneous distribution of components both throughout individual nanoparticles and 100-nm-thick ceramic foil resulting in high structural and optical quality of the obtained samples. The sintered ceramic featured an optical transmission of 77% at 600 nm and above 81% near 2 μm, an average grain size of 24.2 μm and a content of scattering centers of 26.1 ppm. The absorption spectra at several temperatures, from 93 K to 293 K, were measured and the corresponding absorption coefficients were obtained by Lambert-Beer formula in the range from 600 nm to 900 nm and from 1400 nm to 2100 nm. In particular, the room temperature absorption cross section at 794 nm and 1634 nm were determined to be σ abs = 4.25 × 10−21 cm2 and σ abs = 5.01 × 10−21 cm2 respectively. Concerning the emission cross section it was calculated by Fuchtbauer-Ladenburg equation starting from the fluorescence spectrum acquired at the laser work temperature: at 1951 nm and 2106 nm corresponding to the main two emission peaks belonging the curve, it was found σ em = 9.2 × 10−21 cm2 and σ em = 4.9 × 10−21 cm2, respectively. Finally, it was tested the laser behavior of the ceramic: pumped at 793 nm in quasi -CW mode it delivered 1.27 W of output power with a slope efficiency of 10.33% at 2081 nm. The tunability curve spans from 1942 nm to 2110 nm (i. e. 168 nm). • Tm 0.05 (Y 0.5 Sc 0.5) 1.95 O 3 laser ceramic. • Solid-state vacuum sintering from laser-ablated (Tm,Y,Sc) 2 O 3 nanoparticles. • Tm-based laser with emission peak at 2081 nm. • Broad laser wavelength tuning range (from 1942 nm to 2110 nm). [ABSTRACT FROM AUTHOR]

[Display omitted] • Facile microwave combustion synthesis of Cu 1-x Co x Fe 2 O 4 (0 ≤ x ≤ 0.5) NPs is reported. • Synthesis of CuFe 2 O 4 at all Co contents is noticed to be monophasic cubic. • The band gap has been enhanced from 2.30 to 2.50 eV on Co doping. • The M s values are found to be improved from 17.40 to 24.80 emu/g with Co doping. • An enhancement in photocatalytic activity of CuFe 2 O 4 NPs was observed with Co doping. Magnetic nanoparticles are found to have tremendous applications towards opto-magnetic-photocatalytic fields. Hence, herein authors make the efforts to prepare CuFe 2 O 4 (CFe) nanoparticles (NPs) with different Co contents Cu 1- x Co x Fe 2 O 4 (0 ≤ x ≤ 0.5) (CCFe NPs) through microwave combustion process for the first time. Mono phasic preparation of CFe NPs at all Co contents was confirmed via structural analysis. The oxidations states of the prepared NPs were carried out via X-ray photoelectron spectroscopy (XPS). The morphological analysis and chemical compositions of the prepared samples were observed by high resolution scanning electron microscopy (HRSEM) with energy dispersive X-ray spectroscopy (EDX) respectively. Kubelka-Munk model was used to estimate energy gap and found between 2.30 and 2.50 eV. The electron and hole pairs recombination rate and presence of defects were studied via Photoluminescence spectra. The saturation magnetization, M S , remanant magnetization, M r and coercivity, H C were obtained to be improved from 17.40 to 24.80 emu/g, 5.18 to 8.73 emu/g & 331.89 to 1698.12 Oe, respectively. A detailed photocatalytic nature of the prepared CFe and CCFe NPs via hazardous RhB dye degrading beneath of irradiation of visible light (λ > 420 nm) was carried out. The possible mechanism of RhB dye degradation along with optimum Co doping in CFe and commanding active species has been discussed. These outcomes reveal that the Co doping play a key role in improving the optical band gap, magnetic and photocatalytic properties of CFe NPs. [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]

Silver nanoparticles (AgNPs) by green synthesis from fungi polysaccharides are attracting increasing attention owing to their distinctive features and special applications in numerous fields. In this study, a cost-effective and environmentally friendly biosynthesizing AgNPs method with no toxic chemicals involved from the fruiting body polysaccharide of Phlebopus portentosus (PPP) was established and optimized by single factor experiment and response surface methodology. The optimum synthesis conditions of polysaccharide-AgNPs (PPP-AgNPs) were identified to be the reaction time of 140 min, reaction temperature of 94 °C, and the PPP: AgNO 3 ratio of 1:11.5. Formation of PPP-AgNPs was indicated by visual detection of colour change from yellowish to yellowish brown. PPP-AgNPs were characterized by different methods and further evaluated for biological activities. That the Ultraviolet-visible (UV–Vis.) spectroscopy displayed a sharp absorption peak at 420 nm confirmed the formation of AgNPs. Fourier transform infrared (FTIR) analysis detected the presence of various functional groups. The lattice indices of (111), (200), (220), and (331), which indicated a faced-centered-cubic of the Ag crystal structure of PPP-AgNPs, was confirmed by X-ray diffraction (XRD) and the particles were found to be spherical through high resolution transmission electron microscopy (HRTEM). Energy dispersive X-ray spectroscopy (EDS) determined the presence of silver in PPP-AgNPs. The percentage relative composition of elements was determined as silver (Ag) 82.5 % and oxygen (O) 17.5 % for PPP-AgNPs, and did not exhibit any nitrogen peaks. The specific surface area of PPP-AgNPs was calculated to be 0.5750 m2/g with an average pore size of 24.33 nm by BET analysis. The zeta potential was −4.32 mV, which confirmed the stability and an average particle size of 64.5 nm was calculated through dynamic light scattering (DLS). PPP-AgNPs exhibited significant free radical scavenging activity against DPPH with an IC 50 value of 0.1082 mg/mL. The MIC values of PPP-AgNPs for E. coli , S. aureus , C. albicans , C. glabrata , and C. parapsilosis are 0.05 mg/mL. The IC 50 value of the inhibition of PPP-AgNPs against α -glucosidase was 11.1 μg/mL, while the IC 50 values of PPP-AgNPs against HepG2 and MDA-MB-231 cell lines were calculated to be 14.36 ± 0.43 μg/mL and 40.05 ± 2.71 μg/mL, respectively. According to the evaluation, it can be concluded that these green-synthesized and eco-friendly PPP-AgNPs are helpful to improve therapeutics because of significant antioxidant, antimicrobial, antidiabetic, and anticancer properties to provide new possibilities for clinic applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Dissimilar material (Al and steel) tubes have been successfully joined together using magnetic pulse welding technique by setting optimized parameters i.e., discharge voltage and standoff distance. The welded interface has revealed an irregular wavy morphology with melt pockets (max. width ∼20 μm) consisting of intermetallic compound embedded in elemental mixture. High resolution electron microscopy and compositional analysis through energy dispersive x-ray spectroscopy (EDXS) have revealed the formation of 2–3 μm long rod-shaped Fe-Al intermetallic compound. Non-destructive ultrasonic C-scans of the sample welded at 15.5 kV discharge voltage and 1.25 mm air gap have indicated sound welds between the two materials depicting 80% joint integrity while considering the backwall reflection threshold at 50%. The corrosion behaviour at the weld interfaces has been investigated in aqueous solution of 3.5 wt. % NaCl using both potentiodynamic and immersion tests revealing the influence of the intermetallic compound layer on corrosion. [Display omitted] • Non-destructive ultrasonic C-Scan characterization of magnetic pulse welded Al-Steel tubes. • Weld interface consists of 10–20 μm thick melt pockets of Al-Fe intermetallic. • The IMC layer thickness at the interface is directly proportional to the heat input that accelerates the corrosion rate. [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]

The direct vapour transport technique was used to grow novel quaternary In 0.15 Sn 0.85 (Se 0. 95 S 0. 05) 2 crystals. Field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), and energy dispersive X-ray analysis (EDX) with mapping were used to examine the surface morphology and chemical composition of grown crystals. The structural characterisation of grown crystals was analysed by X-ray diffraction (XRD), selected area electron diffraction (SAED), and Raman spectra. The grown crystals have a hexagonal crystalline structure, as confirmed by the structural characterisations. The direct optical bandgap of a grown crystal having 1.37 eV is obtained from absorption spectra. The current–voltage characteristics were studied within the temperature range of 108 K to 403 K. Also, the hall parameters have been obtained at room temperature. The thermodynamic and kinetic parameters were calculated from TGA, DTA, and DTG curves. The photodetector based on grown In 0.15 Sn 0.85 (Se 0. 95 S 0. 05) 2 quaternary crystal exhibits the outstanding self-powered photoresponse. The exhaustive photodetection properties of a photodetector based on a grown In 0.15 Sn 0.85 (Se 0. 95 S 0. 05) 2 crystal were examined as functions of various illumination intensities and wavelengths. Trap depth and photodetection parameters were also calculated. • The direct vapour transport technique was used to grow novel quaternary In 0.15 Sn 0.85 (Se 0.95 S 0.05) 2 crystals. • The grown crystals have a hexagonal crystalline structure, as confirmed by the structural characterisation. • The grown crystals are n-type semiconducting material and have direct optical bandgap of 1.37 eV obtained from hall effect analysis and absorption spectra, respectively. • Thermal degradation analysis has shown good thermal stability at high temperatures. The endothermic compound is showing nonspontaneous dissociation process. • The In 0.15 Sn 0.85 (Se 0.95 S 0.05) 2 quaternary crystal-based photodetector exhibits good self-powered photoresponse with a quick response time. [ABSTRACT FROM AUTHOR]

• The AlSiN coatings were deposited by reactive magnetron sputtering. • Direct evidence of nanocomposite type arrangement in AlSiN ternary coatings. • Structural and mechanical property highly dependent on the nitrogen content. • The mechanical properties of AlSiN coating is optimum at 20:6 Ar:N 2 ratio. • Hardness of 20:6 Ar:N 2 ratio coating is maximum i.e. 31 GPa. In this work AlSiN ternary coatings were deposited by radio frequency magnetron sputtering in Ar/N 2 reactive atmosphere. AlSi alloy target of composition 86:14 wt% has been used to deposit the coatings on float glass substrate by varying the Ar:N 2 ratio i.e., 20:4, 20:6, 20:8, 20:13 and 20:15. The effect of different Ar:N 2 ratio on microstructure, mechanical and optical property were studied using x-ray diffraction (XRD), stylus profilometry, Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDS), High Resolution Transmission Electron Microscopy (HRTEM), UV–visible spectrometry and manoindentation. The XRD measurements show the formation h-AlN phase for coating deposited for 20:6 only and confirm the crystalline nature of the coating whereas at higher and lower Ar: N 2 ratio, the measurements show the amorphous nature of the coatings. 20:6 deposited coating developed a wurtzite-AlN nanocrystalline structure. The thickness of the coatings decreased with respect to the increasing Ar: N 2 ratio. The FESEM shows uneven and dense microstructure of the coatings. HRTEM study confirms the amorphous nature of 20:4 and 20:13 Ar: N 2 ratio, and the polycrystalline nature of 20:6 coating. The elemental compositions were confirmed by EDS. The optical transparency of the coating was more than 95% for all the coatings in the visible range. The roughness of the samples was also measured in scanning probe microscopy imaging that showed an average roughness value Ra of ∼3 nm. The maximum hardness of 31 GPa was observed for the coating prepared with an Ar: N 2 ratio of 20:6. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co doped Ceria, Ce 1-x Co x O 2 (x = 0.1, 0.2, 0.3 mol %) were synthesized by combustion method at 500 °C. • Structure, morphology and spectroscopic studies of the nanopowders were studied. • Room temperature ferromagnetism was observed in this material. In this investigation, cobalt doped ceria nanopowders, Ce 1-x Co x O 2 (x = 0.1, 0.2 and 0.3mol.%) were synthesized by citrate–nitrate auto-combustion method at 500 °C in an open furnace. The prominent X-ray diffraction pattern peaks corresponding to the crystallographic planes (1 1 1), (2 0 0), (2 2 0), (3 1 1), (2 2 2), (4 0 0) and the cell parameters confirm the cubic fluorite crystal structure of the ceria with the help of powder diffraction standard (JCPDS card No.00-034-0394). The UV–Visible absorption due to the charge transfer of O2− → Ce2+ and other functional groups were studied by UV–Visible and FT-IR spectroscopic analyses. The visible light emission (wavelength of 420 nm and 520 nm are corresponding to the defect levels of the O 2p and Ce 4f bands) due to oxygen and other vacancies were confirmed by photoluminescence spectroscopy. Energy band gap (E g) of the Ce 0.9 Co 0.1 O 2 , Ce 0.8 Co 0.2 O 2 and Ce 0.7 Co 0.3 O 2 was found to be 1.423 eV, 1.375 eV and 1.332 eV, respectively. The porosity, agglomeration, particles size, shape and distribution of the synthesized nanoparticles were analyzed by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HR-TEM). The energy dispersive X-ray spectroscopy (EDX) confirms the presence of constituent elements of Ce 1-x Co x O 2 such as Ce, Co, and O. The existence of weak ferromagnetism and its variation due to cobalt concentration were studied by vibrating sample magnetometry (VSM) at room temperature. [ABSTRACT FROM AUTHOR]

• A cheaper synthesis and structural analysis of catalyst to degrade dye is reported. • pH-dependent catalytic activity of CoFe 2 O 4 for cationic & anionic dyes degradation. • Charges on CoFe 2 O 4 were determined by zetapotential evaluation during DLS studies. • A correlation between charges of nanoparticle and dyes molecules in catalysis. This work reports the application of non-functionalized cobalt ferrite (CF) magnetic nanoparticles (MNPs) as a fast dye removing agent. Herein, we have synthesized the CF MNPs by chemical co-precipitation method. The photocatalytic activity is demonstrated with examples of cationic and anionic dyes depending on different pH. The synthesized CF MNPs were characterized by X-ray diffraction (XRD), energy dispersive analysis of X-rays (EDAX), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), selected area electron diffraction (SAED), vibrating sample magnetometer (VSM) and Brunauer-Emmett-Teller measurement (BET) to confirm the structural, morphological, magnetic property and surface area. We have shown its high efficiency in removal of both types of ionic dyes with moderate first order reaction rate under different pH. Because of its magnetic property it is easy to separate from the reaction mixture by magnetic separation method after its use, which is an added advantage in case of recycling. From the application point of view, these MNPs may be useful in promising industrial usage purpose because of its high stability, fast dye removal efficiency and low-cost. [Display omitted] [ABSTRACT FROM AUTHOR]

Aim of present study was to develop biological catalysts of L-arabinose isomerase (L-AI) by immobilizing on four different supports such as multiwalled carbon nanotube (MWCNT), graphene oxide (GOx), Santa Barbara Amorphous (SBA-15) and mobile composite matter (MCM-41). Also, comparative analysis of the developed catalysts was performed to evolve the best in terms of transformation efficiency for D-tagatose production. The developed nano-enzyme conjugates (NECs) were characterized using the high resolution transmission electron microscopy (HR-TEM) and elemental analysis was performed by energy dispersive X-ray spectroscopy (EDS). The functional groups were investigated by Fourier transform infra red spectroscopy. Also, the thermo gravimetric analysis (TGA) was employed to plot a thermal degradation weight loss profile of NECs. The conjugated L-AI with MWCNT and GOx were found to be more promising immobilized catalysts due to their ability to provide more surface area. Conversion of D-Galactose to D-Tagatose at moderate temperature and pH was observed to attain the equilibrium level of transformation (~50%). On the contrary, NECs prepared using SBA-15 and MCM-41 as support matrix were unable to reach the equilibrium level of conversion. Additionally, the developed NECs were suitable for reuse in multiple batch cycles. Thus, promising nanotechnology coupled with biocatalysis made the transformation of D-Galactose into D-tagatose more economically sustainable. [Display omitted] [ABSTRACT FROM AUTHOR]

Assessment of grain boundaries in chromia (Cr 2 O 3) doped fuels has been carried out using high resolution transmission electron microscopy to assess the structure compared to undoped fuel produced via the same process. Chemical analysis of the grain boundary was carried out using Energy Dispersive X-ray Spectroscopy (EDS). It was shown that a relatively disordered phase is formed along the grain boundaries in the doped fuel and that they were chemically enriched in chromium. This has implications for the prediction and understanding of fuel manufacture and in-reactor behaviour as many processes are highly dependant on grain boundary mechanisms. [ABSTRACT FROM AUTHOR]

Sunstar rose ZnO nanoflowers morphology was synthesized using the surfactant-assisted reflux technique. The synthesized 3D ZnO nanoflowers were subjected to various characterization techniques (X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–Vis diffuse reflectance spectroscopy (UV-DRS), Photoluminescence (PL) spectroscopy, Raman spectra, thermogravimetry analysis (TGA), differential thermal analysis (DTA), X-ray photoelectron spectrometer (XPS), N 2 adsorption-desorption isotherms (BET), field emission scanning electron microscopy (FESEM), energy dispersive X-rays analysis (EDAX) and high resolution transmission electron microscopy (HRTEM)). The sunstar rose morphology was achieved under reflux conditions; the heating throughout the material uniformly allowed the nanoflowers to grow along the c-axis due to the temperature, and surfactant also plays a significant role in the shape of the flowers, as confirmed by FESEM and HRTEM analysis. Further, the synthesized 3D ZnO nanoflowers were utilized the photocatalytic activity was investigated for the degradation of hazardous organic dyes like cationic (Methylene blue (MB)) and anionic (Indigo Carmine (IC)) under sunlight. Overall, it was observed that the degradation of MB and IC was found to be 99.5 (50 min) and 98% (60 min), respectively. ZnO nanoflowers are an efficient photocatalyst for MB compared to IC, as MB degrades faster than IC, which takes less time for degradation. Moreover, shown through photocatalytic processes that synthesized ZnO nanoflowers were highly recyclable, suggesting their potential application in environmental remediation. After the fourth cycle, the effective degradation of MB and IC was 78 and 70%, respectively. The radical quenching test shows that ZnO exhibits charge migration, which may account for its high photoactivity. [Display omitted] • Surfactant-assisted reflux was employed to synthesize ZnO sunstar rose nanoflowers morphology for the first time. • Organic dyes like cationic Methylene blue (MB) and anionic Indigo carmine (IC) show effective degradation under sunlight. • The observed degradation of MB and IC was 99.5% (50 min) and 98% (60 min) under the same conditions, respectively. • The photocatalytic degradation efficiency of MB and IC was observed to be 78% and 70% after four cycles. [ABSTRACT FROM AUTHOR]

Artificial enzymes were developed as alternatives to natural enzymes. Considering the unique characteristics of periodic mesoporous organosilica (PMO) materials, a rational design approach was investigated to simulate the coordination sphere around the iron active center in natural horseradish peroxidase (HRP) and fabricate a new peroxidase-like nanozyme. Well-ordered mesoscopic structure, high surface area, tunable pore size, high thermal-hydrothermal stability, and facile surface functionalization are unique properties of PMOs which allow them be potential candidate for enzyme mimic catalysis. In the present study, a monofunctional PMO with ionic-liquid framework (PMO-IL) was prepared as a support to incorporate the iron protoporphyrin IX hemin. The interior surface of mesochannels were also modified by imidazole functional groups. The synthetic peroxidase-like nanomaterial was fully characterized using several techniques such as N 2 adsorption-desorption analysis, Thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) spectroscopy, powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray analysis (EDAX). Peroxidase-like activity of the current nanomaterial was evaluated using 2,2′-Azinobis [3-ethylbenzothiazoline-6-sulfonic acid]-diammonium salt (ABTS) in the presence of hydrogen peroxide in neutral pH condition. Michaelis-Menten kinetic parameters indicated enhanced affinity toward substrate. Results imply that the biomimetic pathways can be developed to achieve a new generation of nanozymes with excellent thermal stability and long-term storage stability which are promising as peroxidase mimics for various applications. [Display omitted] • Introduction of a new generation of nanozymes based on periodic mesoporous organosilica material with ionic-liquid framework. • Simulation of the coordination sphere around the iron active center in natural horseradish peroxidase (HRP). • Fabrication of a stable heterogeneous nanobiocatalyst with peroxidase like activity. [ABSTRACT FROM AUTHOR]

• TiAlVN- Ag coatings were satisfactorily deposited by reactive DC magnetron sputtering. • Dense columnar grain structures were developed during coatings deposition. • Ag nanoparticles amount affected the microstructural and electrochemical behavior. • Protective character of the coatings was confirmed by electrochemical response. Surgical devices and tools are manufactured in AISI 420 martensitic stainless steel, due to its hardenability, adequate hardness and acceptable biocompatibility. Nevertheless, many surface modification strategies are being investigated with a view to improving this material by providing it with self-protection against the colonization of bacteria. One such strategy is the use of a TiAlVN-Ag nanocomposite coating to promote bactericidal effect in surgical devices; however, it is necessary to study the electrochemical response of such coatings to aggressive environments that simulate disinfection and sterilization processes. The aim of this work is to study the relationship between the microstructure, chemical phases and the electrochemical and corrosion response of TiAlVN-Ag coating, varying the amount of silver with the target power increase (0, 50, 70, 80 and 100 W). To study the microstructure, chemical phases, scanning and high resolution transmission electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction were used. Roughness, microhardness, residual stresses, qualitative adhesion of coatings were estimated by atomic force microscopy, Knoop indentation, profilometer and Rockwell C indentation, respectively. Electrochemical behavior and corrosion protection of coatings were studied using electrochemical impedance spectroscopy and potentiodynamic polarization. TiAlVN-Ag 50W coating showed an improvement in electrochemical behavior and in protection of the steel against corrosion and exhibiting higher hardness than that of the AISI 420 stainless steel substrates. This coating exhibited a dense microstructure and high crystallinity, indicating that the low Ag content does not affect the insulating nature of the coating matrix. [ABSTRACT FROM AUTHOR]

An aquatic plant, water hyacinth was used after modification with poly-aniline (PANI@WH) as an adsorbent for removal of Cr (VI) from aqueous solution. The effect of pH, time, dose and concentration on Cr (VI) removal was investigated following batch adsorption process. The adsorption of Cr (VI) on PANI@WH adsorbent followed Freundlich adsorption isotherm as well as pseudo-second-order kinetic model. Maximum adsorption capacity obtained by isotherm has been achieved as 31.45 mgg−1 at 323K. Adsorption of Cr (VI) proceeds through film diffusion rather than intra-particle diffusion. Thermodynamic studies suggested endothermic and spontaneous nature of adsorption due to positive enthalpy and negative Gibbs free energy values. On the basis of the value of mean free energy, Gibb's free energy of adsorption and activation energy obtained in the present investigation suggested that adsorption of Cr (VI) on polyaniline coated water hyacinth occurs through physical adsorption. Surface characterization studies such as Field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared, Brunauer, Emmett and Teller surface area, X-ray photoelectron spectroscopy, X-ray diffractometer, atomic force microscopy and high resolution transmission electron microscopy illustrated adsorption mechanism of the adsorbent. The predicted % removal of Cr (VI) was obtain by response surface methodology model are compared with the experimental % removal of Cr (VI) obtained by batch adsorption process. Prepared composite adsorbent can be reused for several cycles and it gives 85% Cr (VI) removal efficiency even after 4th cycle which shows its good regeneration ability. [Display omitted] • PANI@WH is low cost adsorbent and offered 98.5% Cr (VI) removal. • Freundlich isotherm is followed by Cr(VI) adsorption on PANI@WH. • Cr (VI) adsorption on Cr(VI) on PANI@WH followed physical adsorption. • The adsorption of Cr(VI) on PANI@WH followed pseudo-second-order kinetic model. • FESEM,EDX, and XPS studies confirmed the adsorption of Cr(VI) on PANI@WH. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electrochemical oxidation of formic acid on bimetallic Au@Pd nanoparticles dispersed on a reduced graphene oxide (RGO) support. • Formic acid oxidation Au@Pd/RGO was recorded in a mixed solution of N 2 -saturated 0.5 M H 2 SO 4 and 0.5 M HCOOH at room temperature (RT). • Au@Pd/RGO/RGO showed higher formic acid oxidation activity compared to Pd/RGO, Au-Pd/RGO and Au-Pd /MWCNT catalysts. CO tolerant anode electrocatalysts with promising formic acid oxidation activities are necessary to develop DFACs (direct formic acid fuel cells) as viable renewable energy sources. Here, we report capabilities of bimetallic Au Core –Pd Shell nanoparticles with an average particle size of 5.7 nm strewn across a carbonaceous support made of RGO (reduced graphene oxide), i.e.. for formic acid electrochemical oxidation were elaborated. The microstructural details of as-prepared electrocatalysts were assessed by X-ray diffraction of (XRD), low and high resolution transmission electron microscopy (TEM & HR-TEM) patterns, along with energy dispersive X-ray spectroscopy (EDS) and selected area electron diffraction (SAED) patterns, as well as cyclic voltammetry. At room temperature, nanoparticles' electrocatalytic activity towards formic acid oxidation reaction (FAOR) was measured in a solution made up of N 2 -saturated 0.5 M H 2 SO 4 and 0.5 M HCOOH. Au Core –Pd Shell /RGO catalyst showed higher catalytic performance and more stability towards the FAOR unlike in-house synthesized electrocatalysts like Pd/RGO, Au-Pd/RGO and multi-walled carbon nanotubes (MWCNT)-supported Au-Pd (Au-Pd /MWCNT). [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]

Antibacterial surfaces are a possible way to prevent bacterial infection. This study aim was to prepare antibacterial surface by grafting silver nanoparticles (Ag NPs) onto plasma activated polyethylene terephthalate (PET) surface via biphenyl-4,4ˈ-dithiol (BPD). To take into account the shape factor, which may significantly influence Ag NPs antibacterial properties, two different shape were used, spherical (Ag0) and triangular (Ag3). Ag NPs were characterized using UV–Vis spectroscopy, transmission electron microscopy (TEM) and further by high resolution transmission electron microscopy (HRTEM). Average dimensions of NPs determined by TEM was 21.0 nm for Ag0 and (20.5 x 5.5) nm for Ag3. By HRTEM analysis was shape of Ag0 resolved as decahedron and Ag3 as triangular nanoplates. Success of BPD and Ag NPs grafting onto PET was proved by X-ray photoelectron and energy dispersive X-ray spectroscopy. Antibacterial tests versus E. coli and S. epidermidis were examined on the prepared substrates. Even though the higher amount of Ag was grafted on PET surface with Ag0, in case of S. epidermidis, sample with Ag3 had slightly better antibacterial activity. E. coli, on the other hand, was not affected significantly by the prepared substrates, probably due to low concentration of grafted Ag onto surface. • Polyethyleneterephthalate has been activated by plasma treatment. • Silver nanospheres and triangular nanoplates has been grafted onto PET via BPD. • The effect of shape of grafted NP on bactericidal activity has been evaluated. • The higher bactedricidal effect showed nanoplates due to higher contact area. • Materials could be used in medicine to prevent bacterial contamination of surfaces. [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]

Employing hydrothermal technique, undoped and nickel doped cerium oxide nanoparticles (Ni doped CeO 2 NPs) are synthesized with different concentration of dopant (5 M%, 10 M% and 15 M%). Prepared samples are subjected to Powder X-ray diffraction (PXRD), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), High resolution transmission electron microscopy (HRTEM) with selected area electron diffraction (SAED), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), Ultraviolet–visible spectroscopy (UV–vis), Photoluminescence spectroscopy (PL), Vibrational sample magnetometry (VSM), Dielectric and electrical conductivity studies. Formation of CeO 2 NPs and Ni doped CeO 2 NPs is confirmed by PXRD and EDX. The crystallite size of the samples, determined from powder XRD using Williamson-Hall (W–H) plot, diminishes with increased Ni doping. The lattice parameter variation indicates an initial lattice contraction when the doping is less and a lattice expansion with enhanced Ni doping. These variations in crystallite size and lattice parameter could be due to the replacement of Ce ions by Ni ions in the CeO 2 lattice. SEM and HRTEM images show that the morphology of the NPs formed is nearly spherical. The UV–vis spectroscopic studies indicated that bandgap energy of Ni doped CeO 2 NPs widens as the Ni dopant concentration is increased. Increase of oxygen vacancy (V O) with increase in Ni concentration is designated by Raman spectra. The PL studies show that the nanoparticles of CeO 2 and Ni doped CeO 2 exhibit luminescence in the violet-blue-green wavelengths region (400 nm–500 nm). The decrease in emission intensity with increase of Ni concentration is indicative to increase of oxygen vacancies with increase in Ni content which act as non-radiative centers. VSM studies show that all the samples exhibit paramagnetism. The saturation magnetization and the retentivity of the samples increase as the Ni dopant concentration increases. All the samples display frequency dependent dielectric properties. With increase in the concentration of Ni dopant and frequency, a reduction in the values of dielectric constant and dielectric loss and an improvement in the electrical conductivity were observed for all the samples. [Display omitted] • (Å) could be due to the smaller ionic radius of Ni2+ (0.70 Å) than Ce4+ (0.97 Å). • Ce, Ni & O are present in desired amounts and no other impurities are detected. • TEM suggest that the Ni2+ dopant perhaps inhibit the growth of the cubic phase. • Between cerium cations & oxygen anions is expected to produce anti-ferromagnetic. • Grain boundaries hinder the mobility of electrons between ions. [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]

[Display omitted] • Successful crystallization of Ba 5 (PO 4) 3 OH:Er3+,Yb3+. • Enhanced upconverted visible emission by energy transfer from Yb3+ to Er3+. • Mechanisms of energy transfer from Yb3+ to Er3+. • Potential application of Ba 5 (PO 4) 3 OH:Er3+,Yb3+ in photodynamic therapy. Er3+-Yb3+ co-doped Ba 5 (PO 4) 3 OH nanoparticle powder phosphors were successfully synthesized by urea combustion method. The resulting powder phosphors were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), high resolution scanning electron microscopy (HRSEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy (PL). XRD data confirmed crystallization of pure hexagonal phase of Ba 5 (PO 4) 3 OH and HRSEM images showed formation of ellipsoidal particles. XPS data combined with EDS analysis confirmed the materials composition that corresponds with identification of all the chemical elements constituting the materials. The in vitro dark cytotoxicity of the particles confirmed lack of cytocidal behaviour in the absence of light, but considerable photodynamic therapy (PDT) activity was observed upon illumination. Upon excitation using a 980 nm laser, multiple emission peaks in the green and red regions corresponding to the optical transitions of Er3+ ion were observed. Upon co-doping with Yb3+, upconverted red emission was detected and this was attributable to non-radiative energy transfer from Yb3+ to Er3+. The proposed mechanism of upconversion photoluminescence is discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The role of CNT in promoting crystallinity of composites. • Morphological and structural changes upon thermal treatment. • BiOI together with other phases enhanced photocatalytic activity. • BiOI/CNT composites showed higher photocatalytic activity for phenol and RhB. • Photocatalytic activity is dependent on synthesis, crystallinity and BiOI phases. In this work, we have prepared BiOI/CNT composites by hydrothermal method and studied the impact of CNT and hydrothermal treatment conditions (temperature and time) simultaneously on phenomena such as crystallization. The samples were studied using X-ray Diffraction (XRD), nitrogen sorption (Brunauer–Emmett–Teller (BET) specific surface areas), Scanning Electron Microscopy assisted with Energy Dispersive X-Ray spectroscopy (SEM-EDX), High Resolution Transmission Electron Microscopy (HRTEM), UV–vis Diffuse Reflectance spectroscopy (DRS), Raman spectroscopy and photoluminescence spectroscopy (PL). The different heat treatments applied and varied amount of CNT was found to have a profound effect on the structural, morphological, compositional and optical properties of the prepared composites. The distinguishable changes in the above-mentioned properties were clearly visible for the samples prepared at higher temperature and longer duration (150 °C, 6.30 h). Surprisingly, the presence of other phases of BiOI, such as Bi 7 O 9 I 3 , Bi 4 O 5 I 2 , Bi 5 O 7 I, also co-existed at the same time, although in low amount. Finally, for the study, the photocatalytic efficiency of the prepared samples was tested for phenol and RhB, as model pollutants, under visible light irradiation for 240 min and 120 min, respectively. The results revealed that the composites prepared at higher temperature with longer duration showed superior performance for the photodegradation of phenol and RhB. Additionally, the composites performed better than their respective reference samples in each case. Interestingly, the introduction of CNT promoted the crystallinity in the composites and promising results for the removal of phenol and RhB were achieved by the use of low power ordinary visible lamps. [ABSTRACT FROM AUTHOR]

In the present work, CaWO 4 /Ag 2 MoO 4 nanohybrid was synthesized by sono-chemical method. Fourier-transform infrared spectroscopy (FTIR), UV–visible diffuse reflectance spectroscopy (UV–vis DRS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDAX) and BET surface area analyzer were used to characterize the structure and optical properties of CaWO 4 /Ag 2 MoO 4 nanohybrid. The HRTEM image represents the formation of CaWO 4 /Ag 2 MoO 4 nanohybrid with clear facets and narrow size range. The XRD results showed that CaWO 4 /Ag 2 MoO 4 nanohybrid composed of combined phases of CaWO 4 and Ag 2 MoO 4. A red-shift was observed in the optical absorption of nanohybrid after loading Ag 2 MoO 4 on CaWO 4. The photodegradation of MB by CaWO 4 /Ag 2 MoO 4 nanohybrid (91.4%) showed excellent performance when compared with the pure Ag 2 MoO 4 (59.6%) and CaWO 4 (14.3%) under visible light. The scavenging test revealed that the key species responsible for the degradation of MB dye was hydroxide radical (•OH). The degradation of MB was well fitted to the pseudo-first-order kinetics with a high regression coefficient value (R2 > 0.95). The photostability and reusability of the nanohybrid was studied and the nanohybrid showed almost same degradation efficiency even at 6th cycle. The nanohybrid showed enhanced antimicrobial activity against Escherichia coli and Bacillus subtilis. Therefore, CaWO 4 /Ag 2 MoO 4 nanohybrid photocatalyst can be used as an effective candidate for environmental remediation through photocatalysis and bactericidal applications. • CaWO 4 /Ag 2 MoO 4 nanohybrid was synthesized by sonochemical method. • The CaWO 4 /Ag 2 MoO 4 nanohybrid can able to degrade 91.4% of MB dye in 180 min. • CaWO 4 /Ag 2 MoO 4 nanohybrid demonstrates good photocatalytic activity, photostability and antimicrobial activity. • The active species of photocatalytic activity of nanohybrid was due to the photogenerated hydroxide radicals. [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]

The present work demonstrates that the capability of Al3+ ions as a dopant in the mesoporous tin dioxide (SnO 2) nanopowders for humidity sensor and electrochemical applications. Al3+ ions substituted mesoporous SnO 2 were prepared by facile hydrothermal method. The influence of Al3+ ions concentration on structural, morphological, optical and electrochemical properties of mesoporous SnO 2 were studied in detail using X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), High resolution transmission electron microscopy (HR-TEM), Energy dispersive X-ray analysis (EDX), Fourier transform infrared (FT-IR) spectroscopy, Brunner-Emmett-Teller (BET), Ultra Violet-visible (UV vis.) absorption spectroscopy, Cyclic voltammetry (CV) and Electrochemical impedance spectroscopy (EIS) studies. The electrochemical results indicated that a good electrochemical performance and it can be used in energy storage devices. Besides, higher percentage of Al3+ ions enhanced on the humidity sensitivity at different temperatures and the material exhibit excellent characteristics as humidity sensor. The resistance value decreases with increase of Al3+ ions doping. The increase of humidity sensing response with the increase of Al3+ doping concentration, due to increase of surface area and porosity, which showed the sensing response time and recovery time around 87s and 64s, respectively, and it revealed that the sample has quick response and recovery time. The stability study confirms the Al3+ ions substituted SnO 2 (x = 0.05) sample showed good stability as a humidity sensor. • Al3+ substituted SnO 2 nanopowders were prepared by facile hydrothermal method. • Electrochemical studies indicated a good performance of materials for the use in energy storage devices. • Sn 1-x Al x O 2 (x = 0.05) showed enhanced electrochemical performance compared to other samples. • Humidity sensitivity measurement showed excellent characteristics as humidity sensor. [ABSTRACT FROM AUTHOR]