Study On Preparation And Properties Of Macroscopic Graphene Oxide Nanocomposites

Graphene oxide?GO?is the precursor to prepare graphene by chemical method.Due to a large number of oxygen groups exist on the surface and the edge,GO is easy to modify,functionalize,control and maintain the chemical stability.The graphene-based composites are an important research direction in the field of graphene applications.Graphene-based composites have excellent performance in energy storage,electronic devices,biomaterials,sensing materials and catalyst carriers,and have wide application prospects.Although the raw material graphite sheet has a wide range of sources and low cost,graphene and reduced oxidized graphite are hydrophobic and easy to agglomerate,and make them difficult to give full play to their excellent performance.Therefore,the functionalization of graphene and the preparation of macroscopic materials have been the hot spots of graphene-based material research.In this thesis,graphene oxide is functionalized and self-assembled into macroscopic block or film materials by using inorganic nanomaterials?silver nanoparticles,silica nanowires,titanium dioxide nanotubes?and organic macromolecules??-carrageenan and konjac glucomannan?,and the composites are used into visible light photocatalysis of aromatic compounds and biomimetic materials research.The main contents and results of this thesis are as follows:?1?Self-assembly and easily separable AgNPs/SiO₂NWs/RGO nanocomposites with varying Ag nanoparticles concentrations were fabricated by a simple solution mixing method at room temperature.The results revealed that nanocomposites mostly assembled with each other via intermolecular hydrogen bond and electrostatic adsorption to form the three-dimensional network structure.The hydrophobicity and weak magnetic properties of the material are beneficial for the reuse of materials.The photocatalytic activity was evaluated for 4-nitrophenol reduction by NaBH4.The results demonstrated that all the catalysts exhibited excellent catalytic activity.When AgNPs were added at 10 mL,the composites exhibited the best photocatalytic performance and stability under visible light irradiation.?2?The easily separable Ag-TiO₂/RGO nanocomposites with corrugated 3-D rough fluffy structure was prepared by hydrothermal reaction method at 130 ? for 10 hours.The photocatalytic activities of the prepared nanocomposites were measured by photodegradation of tannic acid under visible light irradiation.Ag-TiO₂ and RGO generated Ti-O-C connection,but the C atoms did not enter the TiO₂ lattice gap.The hydrophobicity of the material facilitated the reuse of the bulk material.When the amount of Ag-TiO₂ was 25 mg,the composite exhibited the best photocatalytic activity and stability under visible light irradiation.?3?A simple solution-casting method was used to mimic the natural nacre and to fabricate the self-assembly and aging-resistant binary natural polymer?k-carrageenan-Konjac glucomannan?-graphene oxide nanocomposites with varying GO contents.The investigation results revealed that k-carrageenan-Konjac glucomannan and graphene oxide mostly assemble with each other via the formation of intermolecular hydrogen bonds to form a well-defined layered structure.GO would agglomerate and become graphite when the GO content was 10 wt%.The addition of GO effectively improved the mechanical properties of the film and achieved the optimum mechanical properties when the GO content was 7.5 wt%.In addition,the composite films demonstrated well reliability and aging-resistant,also displayed a definite tensile strength after cold & hot shock and ozone aging,especially showing a superior ozone resistance.Cytotoxicity test showed that non-toxic high-intensity CKG films had good cell biocompatibility.In this paper,different graphene nanocomposites with different properties were prepared by different materials and methods,and they were expected to be applied in the field of catalysis and biomaterials.