Author/Authors :
Toshitaka Tanabe، نويسنده , ,
Yasutaka Nagai، نويسنده , , Takeshi Hirabayashi، نويسنده , , Nobuyuki Takagi، نويسنده , , Kazuhiko Dohmae، نويسنده , , Naoki Takahashi، نويسنده , , Shin’ichi Matsumoto، نويسنده , , Hirohumi Shinjoh، نويسنده , ,
Junko N. Kondo، نويسنده , , Jaap C. Schouten، نويسنده , , Hidde H. Brongersma، نويسنده ,
Abstract :
Unexpectedly large amounts of CO adsorption have resulted from a pulse adsorption experiment at 323 K, giving about 300% Pt dispersion in a Pt/cerium-based oxide catalyst. An in situ diffuse reflectance infrared Fourier transform spectroscopic investigation on a Pt/cerium-based oxide during CO adsorption has revealed that carbonate species on the cerium oxide surface are responsible for the unrealistically large CO adsorption at 323 K, as a result of CO spillover. Lowering the temperature to 195 K considerably diminished the amount of CO adsorption. The size of the Pt particles in the Pt/cerium-based oxide catalyst was determined by CO pulse adsorption at 195 K and showed good agreement with the particle size determined by X-ray diffraction and low energy ion scattering. This indicates that CO pulse adsorption at 195 K is a useful technique to reliably estimate the Pt particle size in a Pt/cerium-based oxide catalyst.
Keywords :
Cerium-based oxide , Pt particle size , CO adsorption , X-ray diffraction , Low energy ion scattering
