Assembly And Properties Of Oxides/Reduced Graphene Oxide-Based Composites With Core-Shell Structure

As a novel carbon material, graphene possesses unique structure and excellent properties, has been combined with metals, semiconductor materials and yielded a series of composite materials with excellent properties. It has become one of the hot materials in the fields of physics, chemistry and biology. The purpose in this thesis is to prepare reduced graphene oxide-based composites with low cost, high activity and easy recovery. So three kinds of oxides/reduced graphene oxide composites with core-shell structure were designed and prepared. Then, the composition and structure, catalytic performance and interaction mechanism, antistatic performance of the composites were studied. The main content is summarized as follows:A new type of microflowers composed of Fe3O4, reduced graphene oxide (RGO), and Ag nanoparticles (Ag NPs) was prepared by using an electrostatic self-assembly technique followed by a one-step reduction of graphite oxide and Ag+. The as-prepared composite microflowers (Fe3O4/RGO/Ag NPs) were characterized with power X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. Meanwhile, the catalytic activity of Fe3O4/RGO/Ag NPs was studied using Rhodamine B (RhB) as a degradation substrate and NaBH4 as a reducing agent. The results indicated that the catalytic activity of Fe3O4/RGO/Ag NPs was excellent, and the degradation efficiency was up to 100% within 4 min when the loading amounts of RGO and Ag NPs were only about 1% and 1.5%, respectively. The enhanced catalytic activity of the microflowers was attributed to the synergistic effect of RGO and Ag NPs. Moreover, the catalyst can be easily recovered by using a magnet. The Fe3O4/RGO/Ag NPs microflowers could be used as a high-efficiency catalyst for the degradation of hazardous dyes in wastewater.With silica gel as the core, RGO and Ag NPs as the shell, the silica/RGO/Ag NPs composite with core-shell structure was fabricated by an electrostatic self-assembly. It was found that silica gel and reduced graphene oxide can prevent the Ag NPs from aggregating, thus provide more active sites. When the loading amount of Ag NPs is only about 0.78%, RhB solution (25 mL 10 mg L-1) can be completely degraded by the catalyst in 50 s. The defects of traditional catalysts, such as high loading of Ag NPs and low catalytic activity, were overcome. Additionally, the effects of the dosage of NaBH4, the pH value, dosage of the catalyst, concentration of RhB, ions strength and temperature on the degradation of RhB were also studied. The best conditions of the catalytic degradation were achieved.The silica gel/graphene oxide and aminated silica gel/graphene oxide were fabricated. The antistatic performance of the composite was evaluated by testing their surface resistance. The effects of the content of graphene oxide, the reduction methods of graphene oxide and the modification of the silica gel on the antistatic performance of the composite were also investigated. It was found that the reduction of graphene oxide and surface modification of silica gel were negative in improving the antistatic performance of the composites.