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In this work, tin (IV) oxide (SnO2) nanoparticles were synthesized based on Amaranthus spinosus plant. The produced graphene oxide by a modified Hummers' method was functionalized with melamine (mRGO) and used accompanied by natural bentonite (Bnt) and extracted chitosan from shrimp wastes to prepare Bnt-mRGO-CH. This was utilized as novel support for anchoring Pt and SnO2 nanoparticles to prepare the novel Pt-SnO2/Bnt-mRGO-CH catalyst. The crystalline structure, morphology and uniform dispersion of nanoparticles in the prepared catalyst were determined by TEM images and XRD technique. The electrocatalytic performance of the Pt-SnO2/Bnt-mRGO-CH catalyst was evaluated for methanol electro-oxidation through electrochemical investigations including cyclic voltammetry, electrochemical impedance spectroscopy, and chronoamperometry techniques. Pt-SnO2/Bnt-mRGO-CH showed enhanced catalytic activity compared to Pt/Bnt-mRGO-CH and Pt/Bnt-CH catalysts considering its higher electrochemically active surface area, higher mass activity, and better stability for methanol oxidation. SnO2/Bnt-mRGO and Bnt-mRGO nanocomposites were also synthesized and did not show any significant activity for methanol oxidation. The results showed that Pt-SnO2/Bnt-mRGO-CH could be a promising catalyst as anode material in direct methanol fuel cells. [ABSTRACT FROM AUTHOR]

Herein, at first, green SnO2@ZnO nanocomposites were synthesized using Calotropis plant extract as an electron transfer material (ETM) to fabricate low-temperature-processed perovskite solar cells (PSCs). Then, the polyaniline (PANI) polymer was applied as an efficient additive to improve perovskite film quality. Under the effects of the small content of PANI additive, the quality of perovskite films is enhanced, which showed higher crystallinity in (110) crystal plane; also, the perovskite grains were found to be enlarged from 342 to 588 nm. The power conversion efficiency (PCE) of the prepared PSCs with SnO2@ZnO.PANI nanocomposites electron transfer layer (ETL) increased by 3.12%, compared with the PCE of SnO2@ZnO nanocomposites. The perovskite devices using SnO2@ZnO.PANI nanocomposites ETL have shown good stability during 480 h of tests. Furthermore, the optimal PSCs were fabricated by the mp-TiO2/SnO2@ZnO.PANI nanocomposites as ETL, which has a power conversion efficiency of 15.45%. We expect that these results will boost the development of low-temperature ETL, which is essential for the commercializing of high-performance, stable, and flexible perovskite solar cells. [ABSTRACT FROM AUTHOR]

In the present paper, the catalytic activity of a dioxo-molybdenum (VI) unsymmetrical Schiff base complex immobilized on CoFe2O4@SiO2 core–shell nanoparticles (CoFe2O4@SiO2@[MoO2(salenac-OH)] where salenac-OH = [9-(2',4'-dihydroxyphenyl)-5,8-diaza-4-methylnona-2,4,8-trienato](-2)) was studied in the selective oxidation of alcohols using tert-BuOOH (TBHP, 70% aqueous solution) as an oxidant. In this catalytic system, the contribution of different solvents was investigated, and it was found that the various primary and secondary alcohols were oxidized to their equivalent aldehydes and ketones with good to excellent yields (64–97%) at ambient temperature under solvent-free conditions. Moreover, the effect of other essential factors such as the type of oxidant and the quantity of catalyst on the oxidation of benzyl alcohol was explored. Among different oxidants such as H2O2, urea/H2O2 (UHP), tert-BuOOH (TBHP) and NaIO4, tert-BuOOH was selected as oxygen donor, and the oxidation of benzyl alcohol required 50 mg (0.0135 mmol Mo) of catalyst to complete. The CoFe2O4@SiO2@[MoO2(salenac-OH)] catalyst can be conveniently removed from the reaction mixture by using an external magnet and reused four times without notable loss of its catalytic performance. Besides, comparing the X-ray diffraction (XRD) pattern, Fourier transform infrared (FTIR) spectrum, scanning electron microscopy (SEM) image, and energy-dispersive X-ray (EDX) analysis of the recycled catalyst with fresh catalyst showed no significant difference, proving that the catalyst structure remained intact after recovery. [ABSTRACT FROM AUTHOR]

A novel bio‐nanocomposite was developed by incorporating the extracted nanochitosan from shrimp wastes with Schiff base cobalt complex (Chit–Co complex). The phytosynthesis of Chit–Co complex/Ag bio‐nanocomposite was designed utilizing Chit–Co complex at the presence of Ferulago angulate extraction and characterized by AFM, SEM, EDAX, TEM, FT‐IR, and elemental analysis. The radioprotective application of this bio‐nanocomposite on human lymphocyte cells was evaluated using micronucleus (MN) assay. Total antioxidant activities of it were evaluated using FRAP and DPPH assays. Chit–Co complex/Ag bio‐nanocomposite significantly decreased the frequency of micronuclei in human lymphocytes exposed to ionization irradiation (IR). The highest protection was observed at 200 μg/ml. Also, maximum antioxidant activities of bio‐nanocomposite were provided at the same dose. These data exhibit the radioprotective effect of a bio‐nanocomposite based on wastes of living organisms can be an excellent radioprotective agent, which can protect the normal cells of human against the genetic damage by IR. [ABSTRACT FROM AUTHOR]

In this study, ZnO/SnO2 nanocomposites were fabricated via a green and simple route using pine tree leaves for the first time. No expensive reagent or hazardous solvent was used for synthesis of nanocomposites and only natural and eco-friendly materials were utilized. ZnO/SnO2 nanocomposites were characterized by XRD, TEM, SEM and EDS. The adsorption performance of ZnO/SnO2 nanocomposites was studied for the efficient removal of Cu2+, Pb2+ and Zn2+ metal ions. To achieve maximum adsorption capacity of metal ions, the influences of several operating conditions including pH value, ZnO/SnO2 nanocomposites dosage, initial concentration of metal ions and contact time were investigated. Also, equilibrium and kinetics models of metal ions to nanocomposites were studied. Adsorption process could be well defined by the Langmuir isotherm with R2 of 0.88, 0.94 and 0.94 for removal of Cu2+, Pb2+ and Zn2+ ions; respectively. The kinetic data fitted the pseudo-second-order model with the R2 value of 0.99, 1 and 0.99 for removal of Cu2+, Pb2+ and Zn2+ ions; respectively. [ABSTRACT FROM AUTHOR]