Discrete Polyoxopalladates\nas Molecular Precursors for Supported Palladium Metal Nanoparticles\nas Hydrogenation Catalysts

Abstract

We\nhave used discrete polyoxopalladates­(II) (POPs) of the <b>MPd₁₂X₈</b> nanocube- and Pd₁₅X₁₀ nanostar-types (M = central metal ion, X = capping group) as molecular\nprecursors (diameter ca. 1 nm) for the formation of supported (SBA-15)\nmetallic nanoparticles. These materials proved to be highly active\nin the hydrogenation of <i>o</i>-xylene. The characterization\nof such hydrogenation catalysts revealed that the average size of\nthe resulting alloy particles is quite uniform with diameters ranging\nfrom 1 to 3 nm (indicating little to no agglomeration). The central\ntransition-metal ion M^<i>n</i>+ (Mn^II, Fe^III, Co^II, Ni^II, Cu^II, Zn^II, Pd^II) in the POP structure and also\nthe nature of the capping group (AsO₄^3–, SeO₃^2–, PO₄^3–, phenyl-AsO₃^2–) influence the resulting\ncatalytic performance.