Preparation of conductive polypyrrole-palladium composite nanospheres by inverse microemulsion polymerization.

Conductive polypyrrole-palladium (PPy-Pd) composite nanospheres of about 50 nm in diameter, containing dispersed Pd metal nanoparticles of about 2-4 nm in size, were prepared in a 1-step oxidative polymerization of pyrrole by Pd(NO3)2. Pyrrole was oxidized by Pd(NO3)2 in an inverse microemulsion polymerization system, yielding PPy nanospheres and elemental Pd nanoparticles simultaneously. Palladium nanoparticles were uniformly dispersed in the nanospheres of PPy chains. The latter also exhibited an enhanced effective conjugation. The chemical composition of the PPy-Pd composite nanospheres was characterized by X-ray photoelectron spectroscopy and FTIR spectroscopy. The crystalline structure of the Pd nanoparticles was deduced from X-ray diffraction patterns. The morphology of the composites was revealed by scanning and transmission electron microscopy.