Preparation,Characterization,Antibacterial And Catalytic Hydrogenation Properties Of Copper Nanoparticles And Composites

Cu nanoparticles?Cu NPs?and their composite nanomaterials have potential applications in many fields,such as catalysts,antibacterial agents,and transparent electrodes etc.Thus,it has received extensive attention.In this thesis,the Cu NPs and Cu/?-Al₂O₃ nanocomposite with uniform particle size distribution were successfully prepared by clean,highly efficient hydrothermal method and liquid phase reduction method,respectively.The effects of reaction conditions on the particle size and structure of the Cu NPs were investigated in detail.The antibacterial properties of the Cu NPs,organics modified Cu NPs and Cu/?-Al₂O₃ composite were studied,and the antibacterial mechanism was discussed.The catalytic hydrogenation activity of the Cu/?-Al₂O₃ nanocomposites on furfural and catalytic mechanism were investigated.The details are as follows:1.Series of Cu NPs were prepared by hydrothermal method by changing the copper source,surfactant,NaOH concentration and the volume of hydrazine hydrate.The morphology,crystal phase and composition of the series of samples were characterized.The effects of preparation conditions on the particle size,dispersity and antibacterial activity of the Cu NPs were investigated.The results show that the Cu NPs prepared using copper acetate as the copper source,PAA as the surfactant,4 mol·L^-1 NaOH and 0.5 mL hydrazine hydrate,possess the smallest and uniform particle size and good dispersity.With increasing the concentration of NaOH,the antibacterial activity of the as-prepared Cu NPs is significantly improved.In the presence of 0.005 g of the Cu NPs antibacterial agent prepared using 10 mol·L^-1 NaOH,the antibacterial rates against S.aureus and E.coli are as high as 100%in 16 h.2.The Cu/?-Al₂O₃ nanocomposites were prepared by a simple liquid phase reduction method,using copper acetate as a copper source,citric acid as a surfactant,and hydrazine hydrate as a reducing agent.The morphology,structure,functional group,thermal stability and specific surface area of the sample were characterized by SEM,TEM,XRD,FT-IR,XPS,TG,H₂-TPR and BET.The catalytic activity and selectivity of the Cu/?-Al₂O₃ catalyst for furfural hydrogenation to furfuryl alcohol were studied,and the effects of solvent,reaction pressure and reaction temperature on catalytic activity and selectivity were discussed.It was found that the Cu/?-Al₂O₃ catalyst can efficiently catalyze the hydrogenation of furfural to furfuryl alcohol under the conditions of ethanol as solvent,160?,1.5 MPa and H₂ as hydrogen source.The conversion of furfural and the yield of furfuryl alcohol both reach 100%without any by-product,which is of great significance for industrial production.By simulating the adsorption of solvent molecules on Cu atoms,the effect of solvent on the catalytic activity was studied.It was found that methanol molecules are more likely to be activated on the Cu surface than ethanol molecules,resulting in by-products.3.The Cu NPs were modified by CTAB,PVP,PAM and PEG where small amount of organics were introduced into the reaction system.The morphology and crystal phase of the modified Cu NPs were studied.The types of the surface functional groups were investigated by means of Fourier transform infrared spectroscopy?FT-IR?,and the antibacterial properties of the series of organics modified Cu NPs were studied.The results show that the organics were successfully modified onto the Cu NPs by this method.Different organic modifiers have different effects on the antibacterial properties of the Cu NPs.CTAB and PVP can improve the antibacterial activities of the Cu NPs.The antibacterial rates of the un-modified Cu NPs against S.aureus and E.coli were 87%and 57%,respectively.After modification by CTAB and PVP,the antibacterial rates against both bacteria reached 99%.However,the antibacterial activity of PAM and PEG modified Cu NPs was decreased.The antibacterial results show that the?-Al₂O₃ support greatly improved the antibacterial activity of the Cu NPs,which provides a new idea for the development of inorganic broad-spectrum antibacterial agents in the future.