Preparation Of Copper-based Nanomaterials,Antibacterial Activities And Photocatalytic Activities

Copper-based nanomaterials can be widely used in many fields such as photoelectric catalysis,electrochemistry or gas sensors,lithium ion electrode materials and antibacterial materials.In this thesis,series of Cu₂O and Cu nanomaterials were synthesized by a green liquid phase reduction method,and the CuO microspheres were synthesized by hydrothermal method.The as-synthesized samples were characterized by SEM,XRD,TEM,XPS,UV-visible diffuse reflectance absorption spectroscopy and N₂ adsorption-desorption.Meanwhile,their photocatalytic activity and antibacterial activity were studied.The details are as follows:1.The Cu₂O nanomaterials with different particle sizes were prepared by a liquid-phase reduction method at room temperature using ascorbic acid as the reducing agent and glucose as the template.They were characterized by a series of tests.The photocatalytic activity and antibacterial activity of the samples were studied.Especially the photocatalytic activity and photocatalytic mechanism of the Cu₂O nanospheres were systematically studied under different light sources.The results show that the Cu₂O nanospheres exhibit excellent properties in antibacterial and photocatalytic degradation.The low-dose Cu₂O nanosphere catalyst(5 mg),assisted with H₂O₂,exhibits excellent photodegradation activity to 30 mg/L MB solution under the irradiation of UV-visible light or visible light.The Cu₂O catalyst experienced five cycles of photodegradations of MB solutions,and the photodegradation rate hardly changed,indicating that the catalyst has excellent stability.The result of free radical capture experiment shows that h⁺,·OH and·O₂^-are all active substances in the reaction and directly participate in the photocatalytic degradation of MB dye.2.Series of Cu nanoparticles with the average particle sizes of less than 30 nm were successfully synthesized using hydrazine hydrate as the reducing agent.The samples were characterized by a series of tests.The antibacterial activity and the antibacterial mechanism of the sample were studied by means of S.aureus and E.coli.The antibacterial activities of the Cu-based materials(CuO microspheres,Cu₂O nanospheres and Cu nanoparticles)with different particle sizes and crystal phases were tested by comparing their antibacterial rates under the conditions of using the same Cu mole number and the same mass of antibacterial agents.The results show that the antibacterial efficiency of the three Cu-based materials increases with increasing quantity of the sample.No matter using the same mass or the same Cu mole number of antibacterial agents,the order of antibacterial activities of the three samples are CuO>Cu₂O>Cu,which may be related to the specific surface area of the antibacterial agent and the dissolution capacity of Cu²⁺ions.The results of the SEM and XRD of the used antibacterial samples show that the three antibacterial agents have good stability.3.Three kinds of Cu₂O nanoparticles were synthesized by changing the concentration of glucose,using ascorbic acid as the reducing agent.The samples were characterized by a series of tests.Their visible light catalytic activity and antibacterial activity were studied.The results show that the C-doped pure phase Cu₂O nanoparticles(G1 sample)have been successfully obtained.The average particle size of the sample is less than 10 nm,and it has a larger specific surface area and better light absorption ability.The photodegradation rate of MB solution under the irradiation of visible light reached 87.5%at 75 min,indicating its excellent photocatalytic activity.The results of the antibacterial experiments show that the low-dose(3 mg)antibacterial agent(sample G1)exhibits an excellent antibacterial activity against S.aureus and E.coli.Its antibacterial rate remained above 98%after a long culture time,72 h,indicating that the G1 sample has an excellent long-term antibacterial activity.