Synthesis, Characterization And Application Of New Graphene-based Materials Through Cycloaddition Reactions

Graphene is a new type of carbon nonmaterial discovered in2004, which is a two-dimensional, single-layer sheet of sp2hybridized carbon atoms. Due to its unique structure and excellent properties, it has attracted tremendous interest from both experimental and theoretical fields. Although these properties endow graphene great potential in many practical applications, its inertness nature, zero band gap and non-dispersibility in solvents weaken its competitive strength in the synthesis of composites, semiconductors, sensors and etc. Therefore, functionalization of graphene has attracted widespread attention in the past few years. Covalent functionalization of graphene with organic atoms or molecules is of particular interest, as it can combine the unique properties of each component while overcomes the shortcomings of graphene as mentioned above. This paper focus on the functionalization of the graphene through the cycloaddition reactions to produce the new graphene-based materials, and tested their structures and properties by TEM, SEM, FTIR, Raman etc.The main finding are obtained as follows:1. After the reaction of graphene and tetracyanoethylene oxide(TCNEO) via cycloaddition, it obtains a mult-nitrile graphene-based material. The existence of nitrile group in the composite was verified through the detection of infrared spectroscopy. It had been confirmed that the composite contained nitrogen by the XPS analysis. The Raman spectrum analysis determined that the conjugated structure of graphene had been destroyed during the reaction process. Through the analysis of SEM and TEM, it showed that the structure of graphene remained to be semitransparent folded after reaction. EDS analysis indicated that TCNEO had been evenly reacted on the graphene sheet layer in this process.2. Under the cycloaddition, graphene reacts with the condensation compound of paraformaldehyde and tiopronin to form a multi-sulfhygryl graphene-based composite material, with single metallic sliver nanoparticles on the sulfhygryl group in the next step. After the structural analysis of graphene that loaded single silver nanoparticles, the result showed a large number of single silver nanoparticles evenly dispersed on the layer of graphene. The XPS elemental analysis demonstrated that the content of silver reached up to10.58%in the product, the valence state of single metal silver was zero, and the nucleation growth of silver nanoparticles was based on the site of sulfydryl group. In the catalytic reduction reaction of P-nitrophenol, this kind of graphene-based compound with sliver nanoparticle showed an excellent catalytic activity, precedes the traditional catalyst.