REACTIVITY OF SURFACE CARBONYL-COMPLEXES IN NO REDUCTION WITH CO ON COPPER-CONTAINING HIGH-SILICA ZEOLITES

Two mechanisms of NO reduction with CO were revealed on copper-containing hi,oh-silica zeolites. The low-temperature mechanism (below 300 degrees C) involves the interaction between NO and CO adsorbed on Cu+ with the formation of N2O and CO2. The high-temperature mechanism (above 300 degrees C) includes the interaction of CO molecules, adsorbed on Cu+ ions, with NO molecules, adsorbed on copper atoms, with the formation of N-2 and CO2. Under reaction conditions, a surface carbonyl complex, CO-Cu+ is observed. Quantitative spectrokinetic data provide evidence for the intermediacy of the carbonyl complex in both mechanisms. A correlation between the activity in the reaction of NO reduction with CO and the amount of Cu-0 atoms in the sample is found.