Preparation And Application Of Novel Polypyrrole/Carbon Nanocomposites

Graphene and carbon nanotubes as promising candidates of carbon nanomaterials provide enormous potential for high-performance applications in the fields of nanoelectronics, optoelectonics, hydrogen storage, sensors, and supercapacitors based on their unprecedented electronic, optical, mechanical, and chemical properties. Conductive polymers have been extensively investigated for device applications, such as organic light-emitting diodes, photovoltaic cells, organic field-effect transistors, organic lasers, solar cells and supercapacitors either in their neutral states or metallic conductors after doping due to their high energy storage capacity, good electrical conductivity, good redox reversibility and environmental stability. Conductive polymers have been incorporated with carbon materials to form advanced functional nanocomposites which can combine the advantages of the components, and provide platforms for various electronic device applications. In the present paper, we committed to researching the preparation and application of novel conductive polymer modified carbon nanocomposites, the main points of this thesis are summarized as follows:(1) Polypyrrole (PPy) microspheres with high dispersibility and diameters ranging from700to800nm were conveniently synthesized from pyrrole by the initiation of a mixture. Graphite oxide (GO) sheets with negatively charged groups were coated on the surface of PPy templates through electrostatic interactions and π-π accumulation, the product was then reduced by hydrazine. The prepared PPy/RGO core/shell microspheres show admirable sensitivity, selectivity, and stability in the electrochemical detection of DA. The sensitivity of sensor is6.33μA/μM in the linear range of0.01-10μM with a detection limit of1nM, which is greatly improved than those of many recent reports.(2) PPy nanoparticles with high dispersibility had been fabricated through in situ chemical oxidative polymerization and decorated on the surface of GO sheets via electrostatic interactions and π-π accumulation. The hybrids were then reduced by hydrazine and obtained RGO/PPy composites. The decorative PPy nanoparticles could prevent the aggregation of RGO sheets by electrostatic repulsive interaction between them, which lead to a high dispersibility and effective surface area of the composite. Being employed as a sensor for detection of DA, the modified electrode exhibits a sensitivity of7.37μA/μM and detection limit of0.3nM, with linear response in a range of0.001-10μM, and the excellent performace is further confirmed by the detection in real samples (human blood serum and urine).(3) Au nanoparticles decorated PPy/RGO hybrid sheets were facilely fabricated from pyrrole through in situ chemical oxidative polymerization on the surface of GO sheets by the novel initiation of HAuCl4and reduction by hydrazine. The prepared composite is dramatically obtained a crumpled and wrinkled surface, and the flower-like Au nanoparticles are sandwiched by the hybrid sheets, such unique structure could improve the electrochemical activity. Being employed as an electrochemical sensor for detection of DA, the modified electrode exhibits remarkable sensitivity (16.40μA/μM) and lower limit of detection (18.29pM), with linear response in a range of0.1-5000nM. Meanwhile, in the presence of various interfering substances (UA, AA and NE et.), the performance is still very stable.(4) Highly dispersed PPy is firstly designed for decoration onto the surface of pristine multiwalled CNT, which facilely synthesize a CNT/PPy core/shell composite via π-π interaction. The decorative PPy shell could prevent the aggregation of CNT by electrostatic repulsive interaction between them and lead to a high dispersibility and effective surface area of the prepared composite. The hybrid material displayed a high specific capacitance of276.3F g-1in1M KCl electrolyte, four times higher than pristine CNT and86.4%specific capacitance was preserved after1000cycles. Furthermore, the prepared supercapacitor is also capable of delivering an energy density of24.56Wh kg-1at room temperature.