Abstract
Ruthenium oxide particles were introduced into ZSM-5 (MFI type) by aqueous ion exchange and hydrothermal zeolite synthesis methods in the presence or absence of tetrapropyl ammonium ions as organic template. The local structure of ruthenium has been studied by XAS, PXRD, and TEM characterization methods.The aqueous ion exchange method leads to anhydrous ruthenium oxide with average particle size of 2.0 nm by TEM and □ 2 nm by PXRD, while small hydrous ruthenium oxide particles with diameter 0.6 nm are obtained by template-free synthesis. Similar template-free method was applied to introduce ruthenium oxide particles into FAU pores, which leads to hydrous ruthenium oxide with diameter 1.3 nm. In the presence of organic template (TPA), hydrous ruthenium oxide particles were introduced, but after subsequent calcination, large anhydrous ruthenium oxide particles □ 2 nm detected by PXRD were obtained.The effect of solvent, concentration and reduction treatment on the sizes and morphologies on the local structure of platinum, palladium, and gold incorporated in mesoporous silicas were also investigated by XAS characterization method. Pt nanonetworks and nanoparticles were observed in Pt/MCM-48 sample prepared from an aqueous solution and ethanol solution of Pt-precursor, respectively. Different average sizes of Au metals (~3 and ~5 nm) also have been observed in Au/SBA-15 samples reduced under NaBH4 solution and H2 gas flow treatment, respectively.