DRIFTS studies of the interaction of nitric oxide and carbon monoxide on Au-TiO2

DRIFTS data were collected on the interaction of NO and CO over Au/TiO2 prepared by a deposition-precipitation procedure. Reduction of Au/TiO2 in hydrogen at 300 degreesC for 30 min did not completely reduce the catalyst and both ionic and metallic gold sites were found to be present. Adsorption of NO is dominated by the formation of dinitrosyl complexes. CO readily adsorbs on Au/TiO2 leading to multi-bonded carbonyl species. These species readily react with gaseous O-2 to form carbonate species. Displacement of adsorbed CO by gaseous NO showed no interaction between the two adsorbates and there is no experimental evidence for the formation of isocyanate species. This is rationalized in terms of the low tendency of NO to undergo dissociation on Au/TiO2. (C) 2002 Elsevier Science B.V. All rights reserved.