COPPER-ZIRCONIA CATALYSTS FOR NO-CO REACTIONS

Copper-zirconia catalysts have shown high activities and selectivities for a NO-CO reaction at low temperature. Highly active Cu(L) species are produced by replacing the terminal OH groups of the ZrO2 surface a nd assigned to atomically dispersed Cu species. The deactivation of Cu (L) species took place in two steps; relatively rapid activity loss an d subsequent slow deterioration. Treatments with 1% NO regenerated the deactivated Cu/ZrO2 at a much lower temperature than treatments with 5% O-2. The addition of Fe to Cu/ZrO2 was found to dramatically improv e the catalytic performances; the activity and selectivity to N-2 at l ow temperature and catalytic stability. The mechanisms of reaction, de activation, and regeneration are proposed.