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Cu/Ag nanoclusters were grown in a soda-lime glass matrix by an ion-exchange method followed by ultra violet (UV)-irradiation. In this article, the present study has been focused on the nucleation and growth of Cu/Ag nanoclusters under the influence of UV-irradiation. The sizes calculated from the transmission electron microscopy results were closely matched with those obtained from Mie theory-based results. The results revealed that the spherical shaped Cu/Ag nanoclusters were incorporated into the glass matrix under the influence of UV-irradiation and the size of the Cu/Ag nanoclusters varied from 25 nm to 37 nm. The optical, structural, morphological and chemical state were further studied by using UV–Vis. absorption spectroscopy, Raman spectroscopy, X-ray diffraction, Transmission electron microscopy, and X-ray photoelectron spectroscopy. Plasmonic and thermodynamic behaviour of the Cu/Ag nanoclusters were tuned by the UV irradiation and have been explained at variable irradiation time. The distribution and optimization of the Cu/Ag nanoclusters were further investigated using enthalpy (ΔH), entropy (ΔS) and Gibbs energy (ΔG) physicochemical activities and their interdependence for the nucleation and growth of Cu/Ag nanoclusters under the influence of UV irradiation. The UV–irradiation induced and Cu/Ag nanostructure growth process. Their growth impact on optical and thermodynamic properties were explored. Thermodynamic kinetic model for the growth of Cu/Ag NPs: (a) Cu NPS; (b) Ag NPs. Image 1 • Ag/Cu NPs embedded in glass by ion exchange followed by UV-irradiation treatment. • Size of Ag/Cu NPs were confirmed from TEM results. • Nucleation and growth of Ag/Cu NPs studied by thermodynamic Kinetic model. • Surface Analysis confirmed by XPS. [ABSTRACT FROM AUTHOR]

It is of interest to study the magneto-structural coupling in geometrically frustrated antiferromagnets, where structural distortion elevates the ground state degeneracy, leading to a long-range magnetic order. In this regard a cubic spinel compound of the form AB 2 O 4 is currently drawing much attention, where A refers to tetrahedral and B to octahedral sites. In the particular case of NiCr 2 O 4 the material undergoes several structural phase transitions associated with the magnetic ordering. It is therefore necessary to study the magnetic behaviour of NiCr 2 O 4 by substituting either A or B sites, or both systematically with suitable cations. The current work therefore aims at the modification of magnetic properties of NiCr 2 O 4 by doping with Co 2+ at A sites. In order to achieve the afore mentioned, (Ni 1− x Co x )Cr 2 O 4 (0 ≤  x ≤  1) were prepared using chemical co-precipitation techniques. X–ray diffraction (XRD) results indicate that the samples are in the expected phase without any trace of Cr 2 O 3 impurities after calcination. Transmission electron microcopy (TEM) analyses of these samples show that the particles are mostly bi-pyramidal in shape, with sizes ranging from 50 nm to 100 nm. In the present study the ferrimagnetic transition temperatures ( T C ) of the various samples were determined utilizing magnetization as function of temperature measurements. T C for NiCr 2 O 4 and CoCr 2 O 4 was determined to be 82.4 ± 0.8 K and 99.5 ± 0.5 K, respectively. These values are higher than those previously reported in the literature for both these compounds. Substitution of Ni by Co, results in an increase in the T C , giving values of 89.2 ± 0.7 K and 90.6 ± 0.9 K for (Ni 0.5 Co 0.5 )Cr 2 O 4 and (Ni 0.25 Co 0.75 )Cr 2 O 4 , respectively. The (Ni 0.5 Co 0.5 )Cr 2 O 4 sample demonstrated a high coercivity of 3.6 ± 0.1 T and a shift in the hysteresis loop observed under field cooled measurement, not previously reported in literature. X–ray photoelectron spectroscopy (XPS) of (Ni 0.5 Co 0.5 )Cr 2 O 4 suggests that the oxidation states of Ni and Co are 2+, while that of Cr is 3+. In order to investigate the local structure around the cations, low temperature extended x–ray absorption fine structure (EXAFS) measurements were performed. From EXAFS it is confirmed that no redistribution of A and B site cations occur at low temperatures. Present findings demonstrate that the magnetic properties of NiCr 2 O 4 can easily and dramatically be modified by doping Co 2+ at A sites. [ABSTRACT FROM AUTHOR]

The excellent corrosion and wear resistance of titanium carbide gives it a wide range of technological applications. Thin layers Ti (2300 A˚) and C (2020 A˚), were deposited onto SiO2/Si substrates by means of electron beam evaporation in high vacuum. These films were annealed at different temperatures and times (temperatures ranging between 525 and 625 °C and annealing times between 4 and 121 min) to grow thin films of TiC. Ar+ sputter depth profiling, with Auger electron spectroscopy (AES), provided the depth composition of the annealed films. A comparison between AES spectra of C in the graphite and carbide chemical states showed significant differences in both shape and energy of the differentiated peaks. A positive restricted linear least squares (PRLLS) method was used to separate the graphite and carbide contributions from the C profile. The TiC layer thickness for each specimen was obtained. With known TiC thickness and annealing times, the diffusion coefficients as a function of temperature were calculated. An Arrhenius plot yielded an activation energy Q of 207±4 kJ/mol and a pre-exponential factor D0 of 4.1×10−8 m2 s−1. [Copyright &y& Elsevier]

The presence of As(V) and Mn(VII) in water beyond the permissible concentration allowed by World Health Organization (WHO) standard affects human beings, animals and the environment adversely. Hence, there is need for an efficient material to remove these potentially toxic elements from wastewater prior to discharge into water bodies. This research focused on the application of response surface method (RSM) assisted optimization of Fe–Ni/Activated carbon (AC) catalyst for the synthesis of MWCNTs. Also, the MWCNTs was carboxylated and the adsorption behaviors of both nano-adsorbents in the removal of As(V) and Mn(VII) from industrial wastewater was investigated through experimental and computational techniques. The prepared Fe–Ni/AC, MWCNTs and MWCNTs-OCH 2 CO 2 H were characterized using BET, TGA, FTIR, HRSEM, HRTEM, XRD and XPS. The result showed the BET surface area of Fe–Ni/AC, MWCNTs and MWCNTs-OCH 2 CO 2 H were obtained as 1100, 1250 and 1172 m2/g, respectively. Due to the enhanced impact of carboxylation, the adsorption capacity of As(V) and Mn(VII) removal increased from 200 to 192 mg/g for MWCNTs to 250 and 298 mg/g for MWCNTs-OCH 2 CO 2 H. The isotherm and kinetic models were best fitted by Langmuir and pseudo-second order kinetics, while the thermodynamic investigation found that the adsorption process was endothermic, spontaneous and chemisorptions controlled. The regeneration potential of MWCNTs and MWCNTs-OCH 2 CO 2 H after six repeated applications revealed good stability of adsorption efficiency. The study demonstrated optimization importance of Fe–Ni/AC catalyst design for MWCNTs adsorbents and the potentials of utilizing both MWCNTs and MWCNTs-OCH 2 CO 2 H in the removal of selected heavy metals from water and soil. Image 1 • Preparation of bimetallic (Fe–Ni) supported activated carbon catalyst using RSM. • MWCNTs was successfully prepared and functionalized to obtain MWCNTs-OCH 2 CO 2 H. • Carboxylation enhanced the adsorption capacity of MWCNTs-OCH 2 CO 2 H to 250 and 238 mg/g for As(V) and Mn(VII). • Improved adsorption by MWCNTs-OCH 2 CO 2 H was due to metal ions strong binding on carboxyl methoxy groups. • MWCNTs and MWCNTs-OCH 2 CO 2 H significantly treated the wastewater to attain WHO standard for reuse. [ABSTRACT FROM AUTHOR]

Transition metal oxide nanostructures are well known as attractive multi-functional nanomaterials and are among the most promising industrial materials for different science and technology applications. The present study, describes the optical, structural, and antibacterial properties of undoped and Zn-doped CuO nanostructures synthesised by a simple low-cost sol-gel technique. The synthesised nanostructures exhibited a monoclinic CuO structure as confirmed by X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, and high-resolution transmission electron microscopy. Various Zn doping of CuO nanostructures tuned their optical, structural, morphological, and antibacterial properties. Field emission scanning electron microscopy confirmed the formation of bunched cauliflower-shaped nanostructures after Zn doping. X-ray photoelectron spectroscopy was used to study the chemical state of CuO doped with Zn and dynamic light scattering measured the hydrodynamic size of the samples. Zn-doped CuO samples exhibited excellent antibacterial activity against Escherichia coli and Staphylococcus aureus with a change in antibacterial behaviour compared to pure CuO structures. This study demonstrated the potential of using a simple synthesis methodology to produce tuneable nanostructures for multi-functional applications. Schematic mechanism of antibacterial activities of Cauliflower shaped CuO nanostructures doped with Zn with its chemical states. Image 1 • Pure and CuO:Zn nanostructures were synthesised by a simple low cost sol–gel technique. • Cauliflower shaped nanostructures formed after doping with Zn. • Optical tuneable nanostructures obtained for multi-functional applications. • Zn doped CuO samples exhibit excellent antimicrobial activities. [ABSTRACT FROM AUTHOR]

• α-Bi 2 O 3 needles were successfully synthesized via a co-precipitation method. • ESR, XPS and PL results confirmed the presence of oxygen vacancies within the crystal structure. • Green and red emissions were observed in the PL spectra. • The oxygen vacancies increased with an increase in annealing temperature. • Catalytic oxidation of RhB dye occurred by using the α-Bi 2 O 3 in the presence of UV–Vis light. This study investigated the synthesis of α-Bi 2 O 3 needles by a co-precipitation method. The isolated needles were annealed at temperatures ranging from 200 to 700 °C and the possible changes in spectroscopic, structural and optical properties were investigated. Thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, diffuse reflectance, X-ray photoelectron spectroscopy (XPS), electron spin resonance spectroscopy (ESR) and photoluminescence (PL) were used to characterise the synthesized needles. An increase in annealing temperature resulted in a decrease in the band gap values from 2.90 to 2.81 eV. ESR and XPS results confirmed the presence of Bi3+ and oxygen vacancies in the synthesized products, which were responsible for the PL and the observed photocatalytic degradation of the organic dye. The photocatalytic degradation of Rhodamine B dye using the synthesized Bi needles followed pseudo first order kinetics. Results indicated that the 'as-synthesized' Bi 2 O 3 had the highest degradation efficiency (98%) compared to the annealed products and was attributed to the optimum concentration of oxygen vacancies and thus higher surface area. Photocatalysis was found to be very suitable for the removal of the poisonous substances such as dyes from wastewater. [ABSTRACT FROM AUTHOR]

• ZnO:Rb nanoparticles were synthesized by a simple combustion technique. • Rb was homogenously distributed in ZnO with an additional phase Rb 2 ZnO 2. • Clear XPS spectra of the Rb 2 ZnO 2 was obtained. • ZnO:Rb reduced the photocatalytic activities of different dyes. The present work describes the synthesis of pure and Rb doped ZnO (ZnO:Rb) nanoparticles by a simple combustion technique. The surface, structural, optical, morphology and photocatalytic activities of the ZnO:Rb nanoparticles were studied with respect to pure ZnO. X-ray diffraction studies confirmed the presence of a hexagonal wurtzite phase of ZnO and a secondary phase Rb 2 ZnO 2 was also observed with increasing content of Rb into the ZnO. Field emission scanning electron microscopy confirmed an irregular shaped morphology for the ZnO:Rb samples. The X-ray photoelectron spectroscopy results confirmed both ZnO and Rb 2 ZnO 2 , as a new phase. Time of flight secondary ion mass spectroscopy revealed the homogeneous distribution of the Rb in the ZnO and the enrichment of Rb 2 ZnO 2 at the outside and surface of the particles. In the photocatalytic degradation of RhB dye under natural sunlight irradiation, 97.0%, 20.2%, 16.6%, 15.7% and 12.8% degradation was evidenced for ZnO, Rb 5%:ZnO, Rb 7%:ZnO, Rb 10%:ZnO and Rb 15%:ZnO samples, respectively. The result demonstrated that doping ZnO with Rb affects the recombination process of the electron-hole pairs produced by the photon absorption and consequently influence the photocatalytic activity of ZnO. [ABSTRACT FROM AUTHOR]