فهرست مطالب jilla saffari

In this work, La2MnFe2O7 and La2CuFe2O7 photocatalysts were synthesized using a co-precipitation method. The surface morphology, structure, crystalline phase and magnetic behavior of the catalysts were investigated by TEM, FT-IR, XRD, DRS, and VSM. The photocatalytic activity of the La2MnFe2O7 and La2CuFe2O7 nanocomposites were appraised using the optical decomposition of malachite green oxalate (MG), methyl violet (MV), and Eriochrome Black T (EBT) beneath ultraviolet (UV) beam irradiance at different factors like the solution pH, dyes’ concentration, catalysts’ amount, temperature and time of UV light radiation. This research provided the synthesis of new composite magnetic photocatalysts and the study of their effectual in the field of photodegradation of dye pollutants.

Wastewater from textile factories is one of the most important sources of environmental pollution, so it is necessary to treat these wastewater. Therefore, the decomposition of colors using photocatalysts, which is one of the advanced oxidation processes, has been studied. The present work introduces the synthesis of the magnetic mixed metal oxide La2</sub>CoFe2</sub>O7</sub> (LCoFO) nanocomposite as an effective photocatalyst by co-precipitation method. The synthesized metal oxide was characterized by infrared spectroscopy (FT-IR), X-ray diffraction pattern (XRD) and transmission electron microscopy (TEM). The alternating force gradient magnetometer (AGFM) shows the magnetic behavior of the LCoFO nanocomposite. In this research, the photocatalytic properties of LCoFO nanocomposites using photolysis of methyl violet (MV), malachite green oxalate (MG), and eriochrome black T (EBT) were investigated under ultraviolet light irradiation in different parameters such as temperature, solution pH, dye concentration, catalyst amount, and UV radiation time. The results showed that these nanocomposites have good photocatalytic performance.

In this work, NdFeO3 nanoparticles were synthesized through a simple co-precipitation method. The formation of NdFeO3 particles was verified by X-ray powder diffraction, infrared spectroscopy, vibrating sample magnetometer, and transmission electron microscopy analysis. Polyaniline and chitosan were employed as proper support for production of metal nanoparticles. Novel Pt-NFO/PA-CH nanocomposite was fabricated by immobilization of Pt nanoparticles on the PA-CH support in the presence of NdFeO3 nanoparticles. The prepared nanocomposite was characterized by transmission electron microscopy and X-ray powder diffraction analysis. The catalytic performance of the Pt-NFO/PA-CH nanocomposite was evaluated for electro-oxidation of methanol through CO stripping voltammetry, cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. Durability of the Pt-NFO/PA-CH catalyst was investigated and the effects of several factors such as temperature, scan rate, and methanol concentration were studied for methanol oxidation. Enhanced catalytic performance of Pt-NFO/PA-CH nanocatalyst compared to Pt/PA-CH catalyst recommends its application for methanol electro-oxidation in direct methanol fuel cells.

Here, metal nanoparticles were synthesized by chemical reduction of the corresponding metal salts in the presence of chitosan polymer. Binary and ternary metallic-chitosan Pt-Fe-CH, Pt-Co-CH and Pt-Fe-Co-CH nanocomposites were prepared. Transmission electron microscopy images and UV–Vis spectra of the nanocomposites confirmed the presence of the metal nanoparticles. The electrocatalytic activity of the nanocomposites for ethanol oxidation was tested by cyclic voltammetry, Liner Sweep Voltammetry, amperometric i-t curve and electrochemical impedance spectroscopy techniques. The effect of some experimental factors on ethanol oxidation was investigated. CO stripping was used to determine the CO tolerance of the catalysts for ethanol oxidation. Incorporation of small amounts of Co and Fe nanoparticles in the Pt-CH catalyst caused the higher activity of the catalyst for ethanol electrooxidation. The activation energy of Pt-Co-Fe-CH catalyst obtained from the Arrhenius equation was lower than other studied catalysts. These results showed that Pt-Fe-Co-CH catalyst has better catalytic activity for ethanol oxidation among all prepared catalysts.

The perovskite-structured La2CuO4 nanoparticles have been synthesized via an ultrasonic-assisted co-precipitation route using octanoic acid as organic surfactant, and the phase composition, morphology, lattice parameters and size of nanoparticles are characterized through Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and Transmission electron microscopy. Magnetic measurements are carried out by a vibrating sample magnetometer on the resultant powders at room temperature. Vibrating sample magnetometer shows nanoparticles exhibit ferromagnetic behavior. The synthesized perovskite yields comparatively pure crystalline phase of La2CuO4 nanoparticles. These nanoparticles are used as an efficient and effective catalyst for the oxidation of aldehydes to corresponding carboxylic acids, and this oxidation protocol works well for various aldehydes. Also the La2CuO4 nanoparticles can be recycled for several times without obvious loss of activity. The results show the utilization of these nano catalysts have several advantages, viz. high yields, clean reaction, short reaction times and recyclability of the catalyst.

In this work, Pt, Fe and Co nanoparticles were prepared by chemical reduction of the metal salts in chitosan as the support. NaBH4 was used as the reducing agent Pt-Fe, Pt-Co and Pt-Fe-Co-chitosan nanocomposites were synthesized and characterized by UV–Vis spectra and Transmission electron microscopy images. GC/Pt-chitosan, GC/Pt-Co-chitosan, GC/Pt-Fe-chitosan and GC/Pt-Co-Fe-chitosan electrodes were prepared. The performances of these electrodes for methanol electrooxidation were investigated through cyclic voltammetric and chronoamperometric curves. The effect of some experimental factors such as the amounts of Fe and Co nanoparticles dispersed in chitosan, methanol concentration and scan rate were studied and the optimum conditions were determined. The effect of temperature was also investigated and the activation energies were calculated. The performance of Pt-Fe-Co-chitosan nanocomposites was determined in a direct methanol fuel cell in different conditions. The electrochemical and fuel cell measurements showed that Pt-Fe-Co-chitosan nanocatalyst has the best activity for electrooxidation of methanol among all different compositions electrodes.

This paper outlines the synthesis of CuFe2O4 nanoparticles and their catalytic applications. CuFe2O4 nanoparticles were synthesized via microwave-assisted co-precipitation method. The obtained nanoparticles characterized through Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Vibrating sample magnetometer shows nanoparticles exhibit ferromagnetic behavior. CuFe2O4 nanoparticles are used as an efficient and effective catalyst for the one-pot three-component synthesis of 2-naphthol condensed 1,3-oxazinone derivatives. This procedure includes some important aspects like the easy work-up, no need to column chromatography, simple and readily available precursors, and good to high yields.