Study On The Assembly And Electrochemical Properties Of Nano Carbon Composite Materials

With the advantages of low cost, simple operation, good selectivity, high sensitivity, electrochemical sensor can be widely used in medical testing, environmental monitoring, food safety, life science research, etc. As a new type of nano carbon materials, graphene and carbon nanotubes have a high specific surface area, excellent conductivity and excellent electrochemical stability, Graphene and carbon nanotubes can be utilized as the electrode material of the electrochemical sensor. Especially, both graphene and carbon nanotubes have good application prospects in the field of electrochemical detection of drugs, biologically active substances, heavy metal ions, etc.In this paper, the non-covalent modification of the graphene (carbon nanotubes) can be used as the basis, and the graphene (carbon nanotubes) thin films or graphene/carbon nanotube composites with controllable structure were prepared by the method of self-assembly. The electrochemical recognition and detection of the self-assembly product, such as nifedipine, dopamine and other substances, were studied. The detail content is as follows:(1) Using static electricity and hydrogen bond as driving force, the carbon nanotubes/ polyaniline film was prepared by the layer by layer self-assembly method, which was uniform and dense. Electrochemical experiments show that the Self-assembled film can be selectively catalyze electrochemical oxidation of nifedipine. Compared with the undecorated indium tin oxide (ITO), Nifedipine (NIF) in the self-assembly film oxidation potential was reduced by 170mV, and in the concentration range of 1x10-6 mol/L-1x10-4 mol/L, the concentration of nifedipine was proportional to the intensity of the oxidation peak current. Under the same conditions, the electrode preparated by that films has no significant electrochemical response in glucose, urea, ascorbic acid and citric acid sodium solution, and the results show that the electrode can be used as the NIF electrochemical probe.(2)The ureidopyrimidone hydrogen bonding unit was introduced to the surface of reduced graphene oxide (RGO) by means of non-covalent fUnctionalization method aiding by the π-π interaction between pyrene and RGO. Moreover, layer-by-layer (LBL) film of RGO was prepared drived by the hydrogen bonding interaction. The assembled LBL films showed excellent catalytic ability to the electrochemical oxidation of dopamine. The oxidation current of dopamine was in crease 100 times against of bare ITO. Moreover, the peak current increased lineally with concentration of dopamine increased from 1.8×10-5mol/L-2×10-4mol/L.(3)The RGO/CNTs composite was assembled by the corperation of π-π and hydrogen bonding interactions, in which the graphene was wrapped around the wall of carbon nanotube surface. The special structure, endowed the assembled composite excellent electrochemical properties. The current-time plot of the electrode functionalized by the RGO/CNTs composite was sensitive to the concentration of dopamine. Functionalized electrode could be used to determine the concentration of dopamine with the concentration in the range of 5×10-8 mol/L-2×10-6 mol/L, with the low detect limit of 5×10-9 mol/L.