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SnO2 nanoparticles were successfully synthesized by precipitation method, in the presence of hexadecyltrimethyl ammonium bromide (CTAB) and polyethylene glycol 600 (PEG 600) as surfactants. The obtained SnO2 nanoparticles were characterized by X-ray diffraction (XRD), porosity and surface area measurements (BET), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS). Also, photocatalytic properties toward degradation of Rhodamine B (RhB) were investigated. It was found that morpho-structural properties are influenced by the preparative conditions of doped SnO2 nanoparticles. [ABSTRACT FROM AUTHOR]

SnO2 nanoparticles were successfully synthesized by precipitation method, in the presence of hexadecyltrimethyl ammonium bromide (CTAB) and polyethylene glycol 600 (PEG 600) as surfactants. The obtained SnO2 nanoparticles were characterized by X-ray diffraction (XRD), porosity and surface area measurements (BET), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS). Also, photocatalytic properties toward degradation of Rhodamine B (RhB) were investigated. It was found that morpho-structural properties are influenced by the preparative conditions of doped SnO2 nanoparticles. [ABSTRACT FROM AUTHOR]

Fe3O4-SnO2 nanocomposites with SnO2 in the reduced form (without post-annealing) were prepared. X-ray diffraction, high resolution TEM microscopy, X-Ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy and magnetization measurements were used for sample characterizations. Additionally, nitrogen adsorption-desorption isotherms and surface area measurements (BET) were made for porosity and surface area determination. Depending on the amount of SnCl2 used in preparation, tetragonal tin oxide hydroxide Sn6O4(OH)4 or SnO secondary phases were also formed in various samples. XPS analysis shows the presence of surface Sn2+ states and as well as lack, or non-detectable, interstitial tin inside SnO2 nanocrystallites. The presence of Sn2+ surface states determines important changes of both magnetic and photocatalytic properties of samples. Thus Sn2+ surface states determine, on the one hand, an increased efficiency of photocatalytic processes and, on the other hand, a significant decrease of the saturation magnetization of Fe3O4 cores. Moreover, by using ESR spin trapping technique, the generation of reactive oxygen species (·OH, O2·−) resulted by light irradiation of samples was evidenced. [ABSTRACT FROM AUTHOR]

Co x Fe 3− x O 4 ( x =0.5–2.5) magnetic nanoparticles were synthesized via redox reaction between cobalt nitrate, iron nitrate and 1-4-butanediol using five Co/Fe molar ratios, followed by calcination at 1000 °C. Single phase nanoscaled cobalt ferrite was obtained at x =1.0 and at slight Co excess ( x =1.5), while at high Co/Fe molar ratios ( x =2.0 and x =2.5) the prevailing phase was CoO accompanied by CoFe 2 O 4 traces. The highest values of coercive field and saturation magnetization were obtained for the sample at x =1.0, while the lowest values were obtained in the sample with the highest Co excess ( x =2.5). The results indicated that the used synthesis route was suitable for the synthesis of cobalt ferrite with moderate saturation magnetization and high coercive field values. [ABSTRACT FROM AUTHOR]

The Oxygen Evolution Reaction (OER) is crucial in various processes such as hydrogen production via water splitting. Several electrocatalysts, including metal oxides, have been evaluated to enhance the reaction efficiency. Zeolitic Imidazolate Framework-67 (ZIF-67) has been employed as a precursor to produce Co 3 O 4 , showing high OER activity. Additionally, the formation of composites with carbon-based materials improves the activity of these materials. Thus, this work focuses on synthesizing ZIF-67 and commercial activated carbon (AC) composites, which were used as precursors to obtain Co 3 O 4 /C electrocatalysts by calculating ZIF-67/C X ( X = 10, 30, and 50, the mass percentage of AC). The obtained materials were thoroughly characterized by employing X-ray powder diffraction (XRD), confirming the cobalt oxide structure with a sphere-like morphology as observed in the TEM images. The presence of oxygen vacancies was confirmed by infrared spectroscopy and EPR measurements. The electrocatalytic performance in the OER was investigated by linear sweep voltammetry (LSV), which revealed an overpotential of 325 mV at 10 mA cm -2 and a Tafel slope value of 65.32 mV dec -1 for Co 3 O 4 /C10, superior in activity to several previously reported studies in the literature and electrochemical stability of up to 8 hours. The reduced value of charge transfer resistance, high double-layer capacitance, and the presence of Co 3+ ions justify the superior performance of the Co 3 O 4 /C10 electrocatalyst.

The nanocomposite CNT-COOH/MnO 2 /Fe 3 O 4 was synthesized and characterized by different techniques, namely X-ray diffraction, Fourier-transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, energy dispersive spectroscopy, thermogravimetric analysis, Brunauer-Emmett-Teller analysis, magnetic measurement, point of zero charge and hydrophobicity index. Analyzes revealed the groups -COOH, MnO 2 and Fe 3 O 4 attached to the carbon nanotubes, the acidic character of the obtained nanocomposite and its stability. The surface area for the obtained nanocomposite was 114.2 m 2  g -1 . The prepared nanocomposite was used for adsorption of ibuprofen and paracetamol from aqueous solution. Isotherm, kinetic and thermodynamic parameters were determined for predicting the ibuprofen and paracetamol adsorption on synthetized nanocomposite. The equilibrium data obtained from adsorption were well represented by Langmuir model and kinetics data were well fitted by the pseudo-second order model. The maximum adsorption capacity obtained for ibuprofen and paracetamol was 103.093 mg g -1 , 80.645 mg g -1 respectively. The thermodynamic analysis showed that the adsorption process for both pollutants was spontaneous and endothermic. The synthetized nanocomposite can be a suitable new absorbent for ibuprofen and paracetamol removal from aqueous solutions due to its high adsorbing capacity and it can be separated by an external magnetic field., (Copyright © 2020 Elsevier B.V. All rights reserved.)