One-step Preparation Of Polypyrrole-metal(Or Inetal Oxide)Nanocomposites On Cathode And Their Biosensor Application

Simultaneous formation of polypyrrole(PPy)and metal(or metal oxide)composite on a single electrode is particularly challenging because the electrodeposition of PPy and metal(or metal oxide)usually requires opposite potentials.Namely,the preparation of PPy needs an oxidation potential while the metal(or metal oxide)needs a reduction potential.In the present work,nanocomposites of PPy and metal(or metal oxide)were prepared successfully on the cathode by a one-step process,in which V2O5-coated titanium sheet was applied as cathode.In fact,two chemical reactions happened here at the same time.The first reaction was the chemical formation of PPy on the surface of cathode by the use of V2O5 as oxidant and the second reaction was the electrochemical formation of metal(or metal oxide)on the surface of the same cathode.As a result,nanocomposites of PPy and metal(or metal oxide)were one-step prepared on a single electrode.The morphology,composition and structure of nanocomposites were characterized by field emission electron scanning electron microscopy(FESEM),X-ray diffraction(XRD)and energy dispersive X-ray(EDX).Furthermore,PPy-Ag modified electrode was prepared and used as a biosensor to evaluate the electrocatalytic performance of H2O2.It was found that the sensor displayed excellent H2O2-sensing properties and a feasibility for practical applications These results imply that the present one-step process not only presents a simple and efficient method for the formation of PPy-based nanocomposites but also exhibits great potential to improve the application performance and broaden the applied fields of the nanocomposites.This paper is mainly composed of two parts.The main research contents and research results are as follows:(1)PPy-metal(or metal oxide)nanocomposites were prepared at the cathode by one-step method.The feasibility and versatility of the method were investigated.PPy-Sn,PPy-Ag,PPy-ZnO and PPy-NiO/Ni(OH)2 nanocomposites were prepared by designing different electrolyte and electrodeposition conditions.Field emission electron scanning electron microscopy(FESEM).X-ray diffraction(XRD)and energy dispersive X-ray(EDX)were used to characterize the morphology,composition and structure of nanocomposites.It proved the successful preparation of PPy and metal(or metal oxide)nanocomposites.The one-step preparation of polypyrrole and metal(or metal oxide)composites provides a simple and effective method for the formation of PPy-based nanocomposites.The method greatly improves the preparation efficiency of PPy-metal(or metal oxide)nanocomposite,and broadens the range of applications of the nanocomposites.(2)PPy-Ag modified electrode was prepared by one-step method on Au electrode.In order to determine the application value of this strategy,the detection performance in H2O2 enzyme-free sensor was investigated.The performance of the PPy-Ag modified electrode for H2O2 detection was evaluated by electrochemical characterization methods such as cycle cyclic voltammetry and chronoamperometry.The results show that the PPy-Ag modified electrode prepared by one-step method has the advantages of wide detection range,low detection limit,rapid response time and high selectivity for H2O2 non-enzyme detection.The detection performance for H2O2 is equivalent to or better than other Ag-based sensors.Therefore,the strategy presents a promising application value on improving the performance of nanocomposites and broadening the application of relevant fields.