An FTIR and quadrupole mass study of the adsorption and oxidation of C
O on an Au/ZnO sample with O-16(2) and O-18(2) is presented. The resul
ts indicate that CO adsorbed on gold sites at the perimeter interface
with ZnO reacts with surface lattice oxygens at the oxide surface to f
orm carbonate-like intermediates. This reaction and the decomposition
of the intermediates can be assumed to be mainly responsible for the c
onductivity changes of the semiconductive metal oxide caused by CO in
air. Oxygen, present in the mixture and adsorbed on gold vicinal sites
, makes the nucleophilic attack of surface oxygens on the CO easier as
a consequence of an electron-withdrawing effect. This effect produces
a positivization of the carbon of adsorbed CO by an inductive effect
and activates the reactivity of support lattice oxygens on the CO.