NO Reduction by CO over a Pt/Al2O3 Catalyst:  Reaction Kinetics and Experimental Bifurcation Behavior

The kinetic behavior of NO reduction by CO over a Pt/Al2O3 catalyst has been investigated in the temperature range of 465−520 K. The NO + CO reaction exhibits isothermal steady-state multiplicity. A high-conversion steady state was obtained starting with a net oxidizing feed composition ([NO]0 > [CO]0), and a low-conversion steady state was obtained for a net reducing initial feed composition ([NO]0 < [CO]0). A significant amount of N2O was observed as a reaction product, particularly for the high-conversion steady states. The selectivity toward N2O decreased with increasing NO conversion. For the high-conversion steady states, the N2O selectivity decreased rapidly with a decrease in the feed [NO]0/[CO]0 ratio below a critical value of 1.5. The N2O + CO reaction was found to occur to a significant extent. The steady-state bifurcation behavior has been used to discriminate among three kinetic models.