Effect of the support in DE-NOx HC-SCR over transition metal catalysts

Several catalysts based on transition metals (Cu, Co, Fe) and different supports (ZSM-5, activated carbon, Al2O3) have been tested by Temperature-Programmed Reaction (TPR) experiments for the selective catalytic reduction of NOx with propene in the presence of excess oxygen, simulating lean-burn conditions. The activity order with respect to the metal was Cu similar to Fe>Co for all supports used. ZSM-5 catalysts have a superior behavior over Al2O3, as observed for noble metal catalysts. Application of activated carbon as a support is not practical due to its consumption at the reaction temperatures. The selectivity to N-2 of the catalysts was also independent of the support, being higher than 95% in all the cases.