Preparation Of Graphene/Polypyrrole Composite And Its Electrochemical Sensor

As environment continuously deteriorates, our protection consciousness becomes stronger and stronger. Hence we ask for rigorous request for environmental monitoring. As a monitoring tools, electrochemical sensor has lots of advantages, such as high sensitivity, good stability, low cost, simple operation and so on, which attracts more and more scientific workers' attention. It has been widely used in detecting the environmental pollution, life sciences, food and clinical diagnosis, etc.Graphene is a two-dimensional material with a sp2 conjugate benzene six-member structure. It has high specific surface area, high conductivity and stable properties and excellent electric catalytic performance. It was gradually used in the semiconductor industry, photovoltaic industry, lithium ion battery, aerospace, military industry, ultrasensitive sensors since its discovery in 2004. Small molecule substances is easy to absorb on graphene, hence limits its application in sensor. In practical applications, graphene composite is more used, that is, combining graphene with different materials to meet different requirements. Polypyrrole is a kind of conductive polymer materials with high conductivity, its doping is reversible. We can improve its electrochemical properties by different ways, not only can protect graphene, but also improve the sensitivity in sensor.In this article, we synthesized a compound of grapheme/polypyrrole. Firstly, we used improved Hummers method to uniform graphene solution, and then restored it by the means of CV, and deposited it on the electrode surface at the same moment. XRD were used to characterize its morphology and structure. To protect graphene, polypyrrole was covered on the graphene electrode surface by CV method. DPSV method was used to test the cadmium ion. The results showed that graphene/polypyrrole modified glassy carbon electrode had higher peak, better stability, wider linear range compared to pure graphene/GCE and polypyrrole/GCE. And the oxidation peak current was linearly related to the concentration of Cd2+ in the range from 5 to 6000 nmol·L-1, with a correlation coefficient of 1.2×10-9 mol/L(S/N=3).