Electrochemical and chemical interactions between polyaniline and palladium nanoparticles

Electrochemical behavior of polyaniline (PAn) film containing Pd nanoparticles (Pd-NPs) was investigated in propylene carbonate solution. The PAn-Pd particle systems were characterized by using X-ray photoelectron spectroscopy (XPS), UV-visible absorption spectroscopy, and FT-IR spectroscopy. Cyclic voltammetry (CV) and XPS analysis indicated that PAn interacts strongly with Pd-NPs. The electrochemical behavior of PAn film electrode containing Pd-NPs was sensitive to the amount of Pd in the film. From the XPS results, we confirmed that Pd-NPs are stable as metallic state Pd(0) in the PAn-Pd composite film, whereas it exists as ionic state Pd(11) by electrochemical reaction with PAn. Our results indicate that Pd-NPs in the PAn matrix are coordinated to the nitrogen atom of the PAn chain and this leads to the complex formation. (C) 2003 Elsevier B.V. All rights reserved.