Preparation, Characterization And Properties Of Two Kind Of Graphene-based Functional Nanocomposites

Graphene, a new class of carbon nanomaterial, has great properties in electronics, mechanics, thermodynamics and optics owing to its adequate structure. In recent years, the study of graphene-based functional composite materials is one of the most promising fields in nanomaterials. Combined the superior properties of polymers or inorganic materials with graphene, more effective, economic and environmentally friendly composite materials will be prepared, which will lead to another hard-imaging revolution in the field of materials. In this paper, we prepared two kinds of graphene composites, and studied their corresponding applications based on their multifunctional properties.The thesis includes the following three parts:1. A briefly introduce of the basic concept, important properties and research fields of graphene. The preparation of graphene, sort of important graphene derivatives and the graphene-based functional composite materials were reviewed.2. A superparamagnetic Fe3O47/graphene oxide nanocomposite (Fe3O4/GO) was prepared via a simple and effective chemical method. Amino-functionalized Fe3O4(NH2-Fe3O4) particles are firmly deposited on the graphene oxide sheets. The graphene oxide sheets could prevent NH2-Fe3O4particles from agglomeration and enable a good dispersion of these oxide particles. The as-prepared Fe3O4/GO hybrid composite had a much higher thermal stability than graphene oxide. The amount of Fe3O4loaded on GO was estimated as23.6wt%by the atomic absorption spectrometry. The specific saturation magnetization (Ms) of the Fe3O4/GO hybrid composite is15emu g-1. The magnetic Fe3O4/GO composite could be employed as adsorbent for the magnetic separation of dye contaminants in water. The adsorption test of dyes (Methylene Blue (MB) and Neutral Red (NR)) demonstrates that it only takes30min for MB and90min for NR to attain equilibrium. The adsorption capacities for MB and NR in the concentration range studied are167.2and171.3mg g-1, respectively. The Fe3O4/GO hybrid composite can be easily manipulated in magnetic field for desired separation, leading to the removal of dyes from polluted water.3. We developed a "clean" and "wet" route to produce fluorescent CdQ2/GO composites sheets starting from GO and Cd(NO3)2in water/ethanol solution in one pot. Firstly, GO was deprotonated by Na2CO3in order to enhance the ability of coordinating Cd2+. Then the ligand 8-hydroxyquinoline (HQ) was added to form fluorescent CdQ2nanorods. By these means,2D sandwich-like CdQ2/GO composites sheets were constructed in one pot. The as-prepared sandwich-like CdQ2/GO composites exhibited a strong fluorescence emission and high photostability. MTT assay experiment results showed that this kind of composite materials had low cytotoxicity under the concentration of400μg mL-1. The CdQ2/GO composites were found to adhere to the surroundings of the cell membrane, resulting in strong green fluorescence when incubated with Hep G2cells.