Nitrogen-promoted active carbons as DeNOx catalysts: 1. The influence of modification parameters on the structure and catalytic properties

The influence of modification by post-treatment of active carbon with ammonia or urea on catalytic reduction of NO with ammonia was studied. The amount of nitrogen introduced into the structure depended on the pre-treatment of active carbon. The formed N-species were mainly pyridinic or pyrrole/pyridone in nature. No amine, amide or cyano species were found. Both modification procedures (ammonia or urea) led to the increase in activity in SCR and selectivity to N2. The extent of the improvement depended on the pre-oxidation of active carbon before N-introduction and was higher for urea than ammonia treatment.