The Pyridyl Functional Groups Guide the Formation of Pd Nanoparticles Inside A Porous Poly(4-Vinyl-Pyridine)

The reactivity of palladium acetate inside a poly(4-vinylpyridine-co-divinylbenzene) polymer is strongly influenced by the establishment of interaction between the palladium precursor and the pyridyl functional group in the polymer. DRIFT spectroscopy and simultaneous XANES-SAXS have been applied to monitor the reactivity of palladium acetate in presence of H2 and CO as a function of temperature. H2 reduces palladium acetate to palladium nanoparticles and acetic acid. The pyridyl groups in the polymer play a vital role both in stabilizing the formed acetic acid (thus allowing its detection by means of DRIFT) and the final palladium nanoparticles, which are extremely small and mono-dispersed. On the contrary, CO does not reduce palladium acetate. Rather, it forms Pd2+-carbonyl adducts, which favor the detachment of the acetate ligands and their thermal degradation. These adducts are well observable by means of SAXS because they