Iridium particles could be active and selective catalysts for the hydrogenolysis of internal C-C bonds of cyclic molecules, but the preparation and characterization of well-defined iridium metallic particles have not been fully investigated. Iridium particles supported on silica were prepared, beginning with iridium trisacetylacetonate (Ir(AcAc)3). At room temperature, Ir(AcAc)3 was physisorbed onto the surface. The decomposition of the precursor under a flow of hydrogen at 300°C produced metallic particles with narrow distributions of sizes 1-5 nm. The dispersions of the metallic particles inferred from electron microscopy observation was always lower than the dispersions computed from the chemisorption of O2, H2, and CO, assuming the stoichiometry: CO/Irs and O/Irs = 1, H/Irs = 2. The dispersion estimated from the size of the particle could be underestimated.
- H, O, and CO adsorption on Ir
- Heterogeneous catalyst
- Small iridium metallic particles
ASJC Scopus subject areas
- Physical and Theoretical Chemistry