FTIR Study of CO Oxidation on Au/TiO2 at 90 K and Room Temperature. An Insight into the Nature of the Reaction Centers

An FTIR study of CO adsorption and oxidation on Au/TiO2 is reported. At 90 K different CO−18O2 interactions have been performed, with preadsorbed carbon monoxide or preadsorbed isotopically labeled oxygen, with dry or wet carbon monoxide. From the experimental results it can be inferred that (i) at 90 K carbon monoxide and oxygen are molecularly adsorbed on gold particles, (ii) the reaction occurs if carbon monoxide is preadsorbed (it is almost completely inhibited if oxygen is preadsorbed), and (iii) the reaction occurs more easily in the presence of water. It is proposed that dissociation of oxygen is needed in order to observe the oxidation reaction.