Research Of Carbon-based Catalytic Materials Preparation Amd Antibacterial And Antifouling Mechanisms

Marine biofouling is a problem that human beings have to face and solve since the exploitation and utilization of the ocean.Hydrogen peroxide(H₂O₂),as a strong oxidizing and low selectivity oxidant,has been widely used in wastewater treatment,chemical oxidation,bioligical pharmcy and antibacterial,due to its advantages of environmental friendliness and no pollution from degradation products.In situ electrochemical synthesis of H₂O₂ is one particularly important method and can be used in the field of antibacterial and antifouling.Herein,we use carbon-based materials as the substrate materials for electrocatalytic oxygen reduction reaction to H₂O₂.The production H₂O₂ is used for antibacterial and antifouling applications,and E.coli,S.aureus and P.aeruginosa are used as the model bacteria.In addition,the production H₂O₂ can be detected using the carbon-based materials as the simulated enzyme.In order to prevent the corrosion of metal by the excessive H₂O₂,it is further catalyzed to HXO by the haloperoxidase or to·OH according to the Fenton rection.As well we know,HXO and·OH have all strong bacterical properties,which can be used in the research on the biological protect of marine biofouling.It also has important guiding significance for development of advanced biological antifouling technology for marine biofouling.The specific research contents are as follows:(1)Electrocatalytic oxygen reduction to hydrogen peroxide by oxidized graphene aerogel supported cubic Mn CO₃ for antibacteria in neutral mediaWe prepared the oxidized graphene aerogel supported cubic manganese carbonate composites(GO_x/Mn CO₃)with different GO and Mn CO₃ ratio through a simple co-precipitation/in-situ coating method.The characterization results showed that the GO_x/Mn CO₃ composites,with uniformly wrapping of GO on the surface of Mn CO₃cubic,display high conductivity and abundant catalytic sites for 2-electron ORR.The G_0.2M shows the best ORR catalytic performance,onset potential of 0.635 V_RHE,high H₂O₂ production selectivity and high stability in 3.5%Na Cl electrolyte.Based on this,G_0.2M as oxygen reduction electrocatalyst,has good antibacterial effect at 0.55 V_RHEon the stainless-steel.The antibacterial mechanism is mainly due to the electrocatalytic oxygen reaction of H₂O₂ and the side reaction of·OH and O₂^·-.This provides an impressive,effective and environmentally friendly electrochemical approach for antibacterial and antifouling applications.(2)A 3-dimensional C/Ce O₂ hollow nanostructure framework as a peroxidase mimetic,and its application to the colorimetric determination of hydrogen peroxideVarious 3-dimensional C/Ce O₂ hollow nanostructure frameworks(3D C/Ce O₂HNFs)were synthesized by using a polymer blowing process,which is accelerated by adding a certain amount of cerium nitrate.Polyvinylpyrrolidone was used as the polymer.The resulting 3D C/Ce O₂ HNFs were characterized by scanning electron microscopy,energy dispersive spectrometry,X-ray diffraction and X-ray photoelectron spectroscopy.The 3D C/Ce O₂ HNFs possess a large specific surface area,and the Ce O₂ nanocrystals consist of a single phase.The 3D C/Ce O₂ HNFs display intrinsic peroxidase-like activity and can catalyze the oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine in the presence of H₂O₂ to produce a blue product.The method was applied to the quantification of H₂O₂ with a5.2 n M detection limit.The analytical range is from 10 n M to 1?M.(3)Investigating the properties of nano core-shell Ce O₂@C as haloperoxidase mimicry catalyst for antifouling applicationsIn this work,we have successfully synthesized the core-shell structure of Ce O₂@C by using the carbon sphere as template through a simple coprecipitation method.The as-prepared Ce O₂@C is characterized by scanning electron microscopy,transmission electron microscopy,energy dispersive spectrometry,X-ray diffraction,and X-ray photoelectron spectroscopy.The Ce O₂@C displays intrinsic haloperoxidase-like activity via catalyzing the bromination of organic signaling compoundsas well as high stability and recyclability.It can catalyze the oxidation of Br^-with H₂O₂ to the corresponding hypobromous acid(HBr O);the produced HBr O exhibits strong antibacterial activity against Gram-negative(E.coli),Gram-positive(S.aureus)bacteria and typical marine(P.aeruginosa)bacteria.This study introduces a stable,non-poisonous and inexpensive biomimetic material for antibacterial,antifouling and disinfection applications based on novel sustainable and conservation methods.(4)C,N doped Ce O₂ nanoparticles as haloperoxidase mimicry for antifouling applicationsIn this work,we have successfully synthesized the CN-Ce O₂ composites through a simple solid-state synthesis method.The CN-Ce O₂ composites are characterized by scanning electron microscopy,energy dispersive spectrometry and X-ray diffraction spectroscopy.CN-Ce O₂ composites display intrinsic haloperoxidase-like activity via catalyzing the bromination of organic signaling compounds,and present high stability and recyclability in catalytic reactions.On this basis,it can catalyze the oxidation of Br^-with H₂O₂ to the corresponding hypobromous acid(HBr O),and the produced HBr O exhibits strong antibacterial activity.This study introduces a stable,green and environment friendly biomimetic material for antibacterial,antifouling and disinfection applications,which will provide a novel sustainable and conservation methods.