| Graphene,an atom thick material,has many unique properties,such as high specific surface area,high Young’s modulus and tensile strength,as well as high thermal conductivity,these properties have made graphene with great potential in many fields.Graphene aerogels have been widely applied in lithium-ion batteries,supercapacitors,catalysts and adsorbents because of their high porosity,low density and hydrophobicity and hydrophobicity.In this work,graphene oxide was prepared by Hummers method and improved method using graphite as raw materials,and the graphene oxide obtained was characterized and compared with each other.Graphene hydrogels were prepared by reducing agent-assisted self-assembly using graphene oxide as raw materials,followed by ambient pressure drying and freeze drying,the graphene aerogels were obtained.And the adsorption performance for various organic solvents was tested.The specific research in this thesis can be summarized as follows:1.Preparation of graphene oxide.Graphene oxide was prepared by Hummers method and improved method using raw graphite powder.In order to compare the difference between the as prepared samples obtained by Hummers method and improved method,SEM,FTIR,TGA,Raman and XPS were carried out to analyze graphene oxide.2.Preparation of ambient pressure dried graphene aerogel.Graphene aerogel was obtained by ambient pressure drying the as prepared graphene hydrogel which formed using the reducing agent-assisted self-assembly.The effects of types of graphene oxide,the concentration of graphene oxide,the reduction mode and the freezing conditions on the ambient drying were studied.The results showed that,by using graphene oxide prepared by Hummers method as precursor and ascorbic acid as reducing agent,combined with freeze-thaw process,the capillary force in drying process can be effectively reduced and the elastic graphene aerogel can be obtained.3.Preparation of graphene aerogel with freeze drying.Ultralight graphene aerogel was prepared by freeze drying and carbonization process.We have studied the influence of concentration of graphene oxide,reducing agent and other factors on the formation of graphene hydrogel.As a result,we successfully prepared graphene aerogel using graphene oxide obtained with improved method as precursor and triethylene tetramine as reducing agent.The aerogel was characterized and has a broad adsorption capacity for a series of organic solvents,the adsorption capacity was up to 149 times of its own weight when trichloromethane was adsorbed. |
