Preparation Of Graphene Based Composite Materials And Their Sensitive Mechanism

Graphene-based composite materials are widely used in energy and environmental fields because of their unique physical and chemical properties.However,there are still many challenges in the preparation,structure regulation,and practical application of graphene-based composites.In this dissertation,the preparation of graphene-based composites and their catalytic properties were systematically studied.The major research works consists of the following contents:(1)The graphene polymer composite containing polyaniline and chitosan is prepared by electron beam irradiation.When irradiated by electron beam,the solution will be radiolyzed to generate hydroxyl radicals with strong oxidizing properties and reducible solvated electrons.The strong oxidizing properties of hydroxyl radicals allow the monomers to polymerize to produce polymers under acidic conditions.At the same time,the solvated electrons react with silver ions to produce silver nanoparticles.The effects of irradiation doses on the morphology and properties of graphene composites are compared.The structural and electrochemical properties of Ag/PANI-GO and Chitosan/GO composites are investigated.The sensor performance of the graphene polymer composites is tested by assembling an enzyme-free glucose sensor.The H2S-sensitive properties of Ag/PANI-GO are also studied.The results show that the graphene composites prepared by electron beam irradiation have excellent conductivity and good response to glucose.It is expected to find applications in sensors and nanodevices.(2)The graphene nanosieve is designed and synthesized by thermal reduction method.By using Ag-ZnO,ZnO and Ag-ZnO nano-particles to modify the graphene nanosieve,Ag-GNMs,ZnO-GNMs and Ag/ZnO-GNMs series of graphene nanosieve composites are obtained.The effects of reaction conditions on the structure of graphene nanosieve composites were studied by UV spectrum,Raman spectrum and FTIR.The surface-enhanced Raman scattering(SERS)is studied using graphene nanosieve composites as substrates and methyl orange(MO),rhodamine B(RH-6G)and phenanthrenequinone(PQ)as targets.The results showed that GNMs have high sensitivity,and the detection limits for MO,RH-6G,and PQ were 10-11M,10-14M,and 10-13M,respectively.GNMs also have the ability to self-clean,it is possible to develop a rapid,high sensitivity and low-cost SERS detection device which can be reused.GNMs can be also used for the detection of environmental objects such as industrial wastewater.(3)By using graphene oxide synthesized by the modified Hummer method as the carbon material,urea as the nitrogen source,and hydrazine monohydrate as the reducing agent,a series of nitrogen-doped graphene was synthesized by hydrothermal method.The structure and morphology of the nitrogen-doped graphene are studied in detail.The effect of hydrothermal time on nitrogen-doped graphene is also studied.For detecting glucose in biomolecules,nitrogen-doped graphene is used as a carrier to support gold nanoparticles.The effects of synthesis conditions and structure of nitrogen-doped graphene on its sensing characteristics is studied.It is found that Au/N-rGO has a very good linear response to glucose,and the detection sensitivity and error are very close to those of commercial sensors.