Gold catalysts for the abatement of environmentally harmful materials: Modeling the structure dependency

FeOx, TiO2 and CeOx layers were deposited by pulsed laser deposition (PLD) technique onto Au films or Au nanoparticles supported on SiO2/Si(100). The samples were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), secondary ion mass spectrometry (SIMS) and their reactivity was studied in catalytic CO oxidation. Comparison was made with reference samples of FeOx/SiO2/Si(100), TiO2/SiO2/Si(100), CeOx/SiO2/Si(100) and Au/SiO2/Si(100) layers. The catalytic activity of the metal-oxide/Au/SiO2/Si(100) samples must be attributed to active sites located on the metal-oxides overlayer modified by gold underneath, since no Au was exposed to the surface according to the XPS and SIMS. We found a promoting effect of gold on the catalytic activity of the FeOx overlayer and an inhibiting effect of gold on the TiO2 and CeOx overlayers. These findings are discussed in terms of electronic interactions at the Au/metal oxide interface.