摘要

Vibrational IR spectra and light-off investigations show that NH3 forms via the "hydrogen down" reaction of adsorbed CO and NO with hydroxyl groups on a CeO2 support during the catalytic reduction of NO by CO. The presence of water in the reaction stream results in a significant increase in NH3 selectivity. This result is due to water-induced hydroxylation promoting NH3 formation and the competitive adsorption of H2O and NO at the same sites, which inhibits the reactivity of NO reduction by NH3.