Selective catalytic reduction of nitrous oxide by ammonia on iron zeolite beta catalysts in an oxygen rich atmosphere: Effect of iron contents

A series of iron-exchanged zeolite beta (BEA) has been characterized by tem perature programmed desorption (TPD) of oxygen and tested in the catalytic reduction of N2O by NH3. TPD of O-2 has clearly shown that iron-oxo species formed upon reoxidation by nitrous oxide of Fe2+-BEA are more labile than those generated by calcination in ain In the selective catalytic reduction of N2O by NH3 the conversion of N2O increases until a degree of iron exchan ge level of 100% and then decreases. In contrast, the intrinsic activity pe r mole of iron decreases drastically with the increase of iron content. Mon onuclear iron-oxo species have been proposed as the most active sites for t he reduction of N2O by NH3; binuclear iron-oxo species and iron oxides aggr egates are less active. (C) 2001 Academic Press.