Preparation And Performance Studies Of Nitrogen Doped Graphene And Its Composites

Graphene, as the extreme form of graphite, is a new advanced material in the field of materials science due to its charge transport, thermal, optical, and mechanical properties. Because of these prominent properties, graphene has received great attention and been wildly investigated by the scholars. Nitrogen atoms can be used as electron donor to replace carbon atoms in graphene because of its atomic radius like carbon atoms. The nitrogen-doped graphene shows more excellent performance than pure graphene. On the basis of nitrogen-doped graphene, the nitrogen-doped graphene gel and graphene/ZnO composites and graphene/polyaniline composite gel have been prepared and their structure and properties were studied.First of all, nitrogen-doped graphene hydrogels are prepared by hydrothermal reaction in mild conditions. In this reaction, the mixture of ammonia and hydrazine hydrate is used as the reducing agent and nitrogen-doped agent. The dry gel is prepared by freeze-drying. The product is characterized by SEM, XRD, and FTIR. The results confirm that the product has a porous three-dimensional network structure. The water content of the hydrogel is about 99% and the conductivity of dry gel is high. Electrochemical analysis shows that the product possesses high specific capacitance and good cycle stability and rate performance. It can be applied to supercapacitor electrode materials in future.Secondly, the nitrogen-doped graphene and zinc oxide is compounded with a simple mixing method. The results of SEM and XRD indicate that zinc oxide and nitrogen-doped graphene is combined uniformly. The experiment of photodegradation of methyl orange confirms that composite has excellent photocatalytic performance.Finally, the graphene/polyaniline gel materials can be prepared successfully. SEM, XRD, and UV analysis confirm that polyaniline and nitrogen-doped graphene mixed uniformly. Polyaniline attaches to the surface of graphene when the content of polyaniline is less, and polyaniline forms particles on graphene nanosheets when the content of polyaniline is high. Electrochemical testing shows that the composite has a high specific capacitance, excellent cycle stability and rate performance. The product could be potentially used as supercapacitor electrode materials.