Fabrication And Properties Of 3D Graphene Assembly

Graphene, a new kind of material with unique structure, which has excellent physical and chemical properties, can interacting with semiconductor, metal and a series of functional materials to form composite materials with more excellent performance. Therefore, these kinds of materials become a hot research in many fields nowadays. In this literature, we prepared to get some three-dimensional network graphene based composite materials by simple synthesis steps with novel structures, low cost, high activity and easily recovery. On this basis, the three-dimensional graphene composites were further studied about the application of catalytic reduction performance, photocatalytic hydrogen evolution and supercapacitor. The discussion about the research contents are as follows:Graphene oxide (GO) as the assembled unit and glucose as the crosslinked unit, which interact by a one-step hydrothermal synthesis to form three-dimensional graphene composite with high specific surface area. We induced Ag nanoparticles into three-dimensional graphene structure by in situ reduction method, finally we obtained the graphene aerogel with Ag nanoparticles (3DGA/Ag). SEM, TEM, FT-IR spectra, XPS, BET, Raman spectra and XRD are used to study the physical and chemical characteristics of the 3DGA/Ag composite.Meanwhile, we study the catalytic activity and stability performance of the composite by reducing 4-NP into 4-amino phenol (4-AP) under different experimental conditions. The results show that the three-dimensional structure of graphene aerogel can effectively inhibit the aggregation of Ag nanoparticles, thus provide more active sites. When Ag nanoparticles loaded was about 20%, higher catalytic activity was exhibited. Under the flowing system, it can transfer 4-NP into 4-AP fastly at room temperature, 3DGA/Ag composite can degrade 100 mL 0.15 mmol L-1 4-NP closely completely under 16 minutes.Using TETA molecule as connected unit to form 3D graphene composite by one step hydrothermal method. Then, CuO nanoparticles were induced into the structure of 3D graphene composite by in situ reduction method. On this basis, using Eosin Y as the light capture unit and studying the performance of the photocatalytic hydrogen evolution of the composite. At the same time, the catalytic stability of the photocatalytic hydrogen evolution and the photocatalytic performance of the composite were studied. The results showed that the prepared composite has excellent photocatalytic hydrogen evolution under the optimal conditions, and the catalytic hydrogen production efficiency can reach 5.58 mmol g-1 h-1,which is about 2.3 times comparing to the CuO loaded on the graphene nanosheets. And the catalytic stability is also satisfactory. In addition, the mechanism of photocatalytic hydrogen evolution was also discussed. The research showed that CuO nanoparticles act as the active site of splitting water into hydrogen in the photocatalytic process. The 3D graphene assembly also plays an important role in the photocatalytic system. It can not only improve photoinduced electron transfer, but also can make the sacrifice agent absorb on the surface of the catalyst sufficiently and enhance the efficient of H2 diffusion from the structure. These results may give new idea for obtaining higher efficient visible light catalyst.One step hydrothermal method and in situ photoreduction method were used to prepare CuO nanoparticles loading into the structure of 3D graphene assembly, which consists of TETA connecting with graphene sheets together. Meanwhile, tests the possibility of the 3D graphene assembly in the field of the supercapacitor. The results showed that the 3D graphene assembly is a very promising material in supercapacitors, which achieved a high charge-discharge capacity and the discharge capacity can reach as high as 154 F/g at room temperature, this excellent charge-discharge properties may stem from high specific surface area and good conductive performance of 3D graphene assembly. In addition, the synergistic effect between CuO nanoparticles and graphene nanosheets also play an important role.Through our research, we further recognize that the 3D graphene assembly not only can keep the intrinsic properties of graphene sheets, but as aslo show some other new properties.These new features would give new thought to design and develop novel composites, which are of simple synthesis steps, novel structure and also provide us new idea to achieve graphene based functional materials with excellent performance.