SERS, XPS and DFT investigation on palladium surfaces coated with 2,2′-bipyridine monolayers

Il manoscritto riporta sulla produzione e caratterizzazione di superfici di Pd ricoperte con 2,2'-bipiridina. Tali superfici risultano strutturalmente e chimicamente simili a quelle dei complessi di PdCl con la bipiridina , composti questi attivamente utilizzati in catalisi omogenea. L'utilizzo di superfici di Pd , meglio se sottoforma di nanoparticelle legate con la bipiridina, vengono proposti come candidati per applicazione in catalisi eterogenea. Palladium surfaces, pretreated with a solution of 2,2′-bipyridine (bpy) as ligand molecule, were SERS-activated by means of laser-ablated Ag colloidal nanoparticles. XPS and Raman measurements, along with DFT simulations, evidenced the species formed on the metal surface as bpy-Pd(OH)2, which appears quite similar, from both structural and spectroscopic points of view, to the bpy-PdCl2coordination compound, whose catalytic activity is well known. Based on these observations, the use of Pd substrates coated with bpy is proposed for reactions of heterogeneous catalysis, instead of using bpy-PdCl2 as homogeneous catalyst. Moreover, palladium nanoparticles could be prepared by laser ablation in aqueous solution of bpy, exhibiting both colloidal stability and catalytic activity.