Kinetic study on the selective catalytic reduction of NO with NH₃ over iron-cerium mixed oxide

Iron-cerium mixed metal oxide (Fe_0.95Ce_0.05O_z) was prepared through co-precipitation method and used as the catalyst in the selective catalytic reduction of NO with NH₃ (NH₃-SCR); the effects of initial concentration of NO, molar ratio of NH₃/NO and O₂ concentration on its NH₃-SCR activity were investigated in an integral reactor at steady-state and the kinetics were considered in a differential reactor. The results indicated that the amount of NO converted over per unit catalyst increases with the initial concentration of NO; with the increase of NH₃/NO mol ratio, NO conversion is firstly increased sharply and then gradually reaches a stable value; O₂ in the flue gas also plays an important role in the NH₃-SCR reaction. The NH₃-SCR reaction over Fe_0.95Ce_0.05O_z exhibits first-order with respect to NO, zero-order to NH₃, and nearly 0.5-order to O₂ at 175~275 ℃; the apparent activation energy is 42.6 kJ/mol.