Synchrotron radiation photoelectron spectroscopy study of metal-oxide thin film catalysts: Pt-CeO2 coated CNTs
2012
Abstrakt
The interaction of Pt with CeO2 layers was investigated by using high resolution hard X-ray photoelectron spectroscopy. Pt doped CeO2 layers were deposited simultaneously by rf-magnetron sputtering on a SiO2/Si substrate and carbon nanotubes (CNTs) grown on a carbon diffusion layer of a polymer membrane fuel cell.
In the case of the CNT support photoelectron spectra showed the formation of ionic platinum rich cerium oxide with Pt2+,(4+) species, and with the Pt2+/Pt4+ ratio strongly dependent on the amount of platinum. Ce reveals 4+/3+ mixed valent character with Ce3+ concentration increasing with Pt content.
In the case of the SiO2/Si substrate the film revealed Ce4+ and Pt4+ species only.