BIMETAL/CARBON NANOCOMPOSITES CuCo@C BASED ON SYNTHETIC HUMIC ACIDS

The new original method for the synthesis of bimetal-carbon nanocomposites of copper and cobalt (CuCo@C) of various compositions using synthetic humic acid as a carbon source has been developed. The technique includes the synthesis of humates of copper and cobalt, preparation of their mixture and its pyrolysis in a hydrogen atmosphere. For characterize the final product, the methods of diffraction, cyclic voltammetry, and scanning electron microscopy were used. Comparison of diffractograms of bimetal nanocomposites shown two systems of reflexes from fcc structures, which correspond to metallic copper and cobalt. Diffractometric measurements also indicate the amorphous nature of the carbon matrix. Carrying out the pyrolysis of the metal humates in the reducing atmosphere afford remove almost completely the contained oxygen from the final product, partly in the form of CO2, partly in the form of water. Ions of the transition metal in these conditions are reduced to the metal atoms, forming nanoparticles surrounded by carbon. The formation of a carbon matrix metal around nanoparticles, on the one hand, can ensure their high thermal stability, and on the other hand, contributes to the stabilization of metal nanoparticles and prevents their aggregation. The size of cobalt nanoparticles in nanocomposites varies from 35 to 54 nm, and copper nanoparticles - from 56 to 88 nm, depending on the ratio used in the synthesis of metal humates. It was found that nanoparticles of an alloy of these metals (alpha-cobalt phase) are formed in nanocomposites containing 20% ​​copper and 80% cobalt. Cyclic voltammogrames of bimetallic nanocomposites indicate the presence of dead pores in their composition. It has been established by scanning electron microscopy that in the case of an excess amount of copper in the nanocomposites, spherical formations about 1000 nm in size with faceting signs are formed. As part of the «bottom up» concept proposed a three-stage model of formation.

Green Synthesis of Ag-Au Bimetallic Nanocomposites Using Waste Tea Leaves Extract for Degradation Congo Red and 4-Nitrophenol

A sustainable supply of pure water is a great challenge in most developing and third-world countries. Nanomaterial-based technology offers technological development for wastewater purification. Nanocatalysis hydrogenation of nitroarene and dye molecules is a hot model in many research fields. Herein, we report eco-friendly and facile technology to synthesize Ag-Au bimetallic nanocomposites. The synthesized nanocomposites are characterized by ultraviolet–visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy and high-resolution transmission electron microscopy. The synthesized nanocomposite can efficiently degrade Congo red and 4-nitrophenol in water and in the presence of sodium borohydride. The results show that it degrades Congo red and 4-nitrophenol entirely within 6 and 7 min, respectively. These results could be useful for the green synthesis of Ag-Au bimetallic nanocomposites and help to remove organic dye molecules and nitroaromatics from wastewater.

Superior co-catalysis by bimetallic nanostructure for TiO2 photocatalysis

Background:: Bimetallic nanocomposites have currently gained significant importance for enhanced catalytic applications relative to monometallic analogues. The synergistic interactions modified electronic and optical properties in the bimetallic (M1@M2) structural morphology e.g., core-shell /alloy nanostructures resulted in a better co-catalytic performance for TiO2 photocatalysis. Objective:: Hence, this article discusses the preparation, characterization, and co-catalytic activity of different bimetallic nanostructures namely, Cu@Zn, Pd@Au, Au@Ag, and Ag@Cu, etc. Method:: These bimetallic co-catalysts deposited on TiO2 possess the ability to absorb visible light due to surface plasmonic absorption and are also expected to display the new properties due to synergy between two distinct metals. As a result, they reveal the highest level of activity than the monometal deposited TiO2. Result:: Their optical absorption, emission, charge carrier dynamics, and surface structural morphology are explained for the improved photocatalytic activity of M1@M2 loaded TiO2 for the hydrogenation of certain organic compounds e.g., quinoline, crotonaldehyde, and 1,3-dinitrobenzene, etc. under UV/ visible light irradiation. Conclusion:: It revealed that the use of bimetallic core@shell co-catalyst for hydrogenation of important industrial organics by M1@M2-TiO2 nanocomposite demonstrates beneficial reactivity in many instances relative to conventional transition metal catalysts.

In situ generation of antibacterial bimetallic silver and copper nanocomposites using Tinospora cordifolia leaf extract as bio reductant

The method of in situ generation was employed to produce binary silver and copper bimetallic nanocomposites (BNCFs) using lesser emission pollutant biological plant species i.e., Tinospora cordifolia (TC) leaf broth as reducing agent. The generated BNCFs were confirmed by different spectrophotometric studies i.e. Fourier Transform Infrared (FTIR), Scanning Electron Microscope (SEM) along with Energy Dispersive X-ray (EDX), X-ray Diffractometer (XRD), Primary and Secondary thermogravimetric (TG & DTG) analysis and Differential Scanning Calorimetry (DSC). The bio synthesized nanocomposite cotton fabrics (NCFs) were found to be spherical in shape and with an average size of 80nm from SEM analysis. The elements silver and copper were confirmed by observing peaks at 3keV and 1keV, respectively, from EDX spectra. The XRD studies revealed the crystalline nature of BNCFs. TG and DTG analysis explained the catalytic activity of silver and copper with lesser thermal stability. The BNCFs showed good tensile properties, using universal testing machine. The BNCFs also exhibited good antibacterial activity against disease producing G+ve and G-Ve bacteria. The BNCFs mat be considered to make bandage cloths, napkins etc., in the medical field.