Interfacial assembly of Pt nanoparticle-doped free-standing polymer foam films and their catalytic performance

Free-standing thin films of poly(2-vinylpyridine) (P2VP) doped with platinum complex ions were fabricated at the planar aqueous solution of H2PtCl6/chloroform solution of P2VP interface. The formation of the free-standing thin films was attributed to the adsorption and combination of the polymer molecules and the complex ions at the interface, and self-assembly of the composites. The films were composed of thin layers decorated with separated and conglutinated microcapsules. After treatment with KBH4 aqueous solution, the platinum complex ions incorporated in the polymer matrices transformed to platinum nanoparticles with the mean size of 2.2 nm, which was confirmed by transmission electron microscopic investigations and X-ray photoelectron spectroscopic (XPS) analysis of the samples. Both the contents of the platinum element in the untreated and treated composite films estimated based on the thermagravimetric analysis (TGA) were close to each other, indicating no loss of platinum during the treatment process. The catalytic activity of the composite films was evaluated by using the reduction of 4-nitrophenol by KBH4 in aqueous solutions. The results indicated that the composite films have high and durable catalytic activity.