The CO oxidation over Co3O4 and Co3O4/Al2O3 has been investigated using flo
w reactor and in situ FTIR studies. Cobalt oxide shows very high activity e
ven at room temperature. However, a gradual deactivation takes place during
reaction. The deactivated catalyst shows the presence of two different car
bonate species and one graphite-like species. A possible mechanism for the
deactivation is discussed.