IRON-OXIDE SUPPORTED GOLD CATALYSTS DERIVED FROM GOLD-PHOSPHINE COMPLEX AU(PPH3)(NO3) - STATE AND STRUCTURE OF THE SUPPORT

Iron oxide supported gold catalysts were prepared by supporting the Au -phosphine complex Au(PPh3)(NO3) onto various iron oxide supports. Amo ng the prepared catalysts only the use of amorphous as-precipitated ir on hydroxide Fe(OH)(3) as a support for Au(PPh3)(NO3) allowed us to o btain the tremendously active catalytic material for low-temperature C O oxidation. The supports and the Au catalysts were characterized by B ET, SEM, XRD, FT-IR, XPS, and Raman. Initial structures of the employe d supports were found to influence dramatically the gold particle size and the catalytic activity. The most active catalyst consisted of sma ll gold particles and poorly crystallized iron oxide support with a mi xture of alpha-Fe2O3 and gamma-Fe2O3. The gamma-Fe2O3 formation occurr ed by the presence of the PPh3 as a ligand for gold. The presence of g amma-Fe2O3 influenced positively the catalytic activity of the Au-cont aining samples. (C) 1998 Academic Press.