Polyaniline-Pt and polypyrrole-Pt nanocomposites: Effect of supporting type and morphology on the nanoparticles size and distribution

• Size and distribution of nanoparticles are sensitive to the matrix morphology.
• Nanofibers provide large number of heterogeneous nucleation sites for nanoparticles.
• Polyaniline chemical composition is a key factor to control size and distribution.

The size and the distribution of platinum nanoparticles on the polyaniline-Pt (PANI-Pt) and polypyrrole-Pt (PPy-Pt) nanocomposites are extremely sensitive to the polymer matrix morphology. This is observed when the polymer matrix morphology was changed from nanofibers to nanotubes. TEM results showed platinum nanoparticles with size diameter as low as 2 nm in the case of polpyrrole nanofiber and polyaniline nanofiber matrices. In addition, FTIR and UV–vis results showed that polyaniline matrix with different morphologies, nanofibers and nanotubes, presented different chemical structures, which resulted in a different size and distribution of the platinum nanoparticles, as it was observed from the SEM, platinum X-ray mapping and TEM results. The DSC thermal analysis results showed that the presence of platinum nanoparticles in the polymer matrix resulted in a greater thermal stability when compared to the polymer matrix. It was the first time that the effect of PANI and PPy morphology on the platinum dispersion and distribution is demonstrated.