Preparation of Nanocomposites of Polypyrrole-metal (or Metal Oxide) on the Surface of V₂O₅ Coated Cathode through a One-step Method

Simultaneous formation of polypyrrole (PPy) and metal (or metal oxide) 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 preparation of PPy on the 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 investigated via field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD). Furthermore, PPy-Ag nanocomposite was prepared and used as a sensor 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, facial and efficient way 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. (paper)