The Pt/TiO2, Pt/ZrO2, and Pt/Al2O3 catalysts submitted to low-temperature r
eduction (LTR, 200 degrees C) and high-temperature reduction (HTR, 500 degr
ees C) and exposed to hydrogen and carbon monoxide at room temperature were
studied by infrared spectroscopy. There is a strong loss of transmission i
n the entire infrared spectra on Pt/TiO2 after its exposure to hydrogen, wh
ich is related to the reducibility of the support. A typical SMSI behavior
(strong metal-support interaction), such as the decrease in carbon monoxide
adsorption capacity, was detected on Pt/TiO2 and Pt/ZrO2 after exposure to
hydrogen, even for the catalysts submitted to LTR treatment. Also a carbon
yl band shift to lower wavenumber was observed on LTR-treated Pt/TiO2, Pt/Z
rO2, and Pt/Al2O3 after exposure to hydrogen. We interpreted this SMSI beha
vior as an electronic rather than morphological effect, which was induced b
y the presence of hydrogen spillover.