A kinetic model of the hydrogen assisted selective catalytic reduction of NO with ammonia over Ag/Al 2 O 3

A global kinetic model which describes H 2 ‐assisted NH 3 ‐SCR over an Ag/Al 2 O 3 monolith catalyst has been developed. The intention is that the model can be applied for dosing NH 3 and H 2 to an Ag/Al 2 O 3 catalyst in a real automotive application as well as contribute to an increased understanding of the reaction mechanism for NH 3 ‐SCR. Therefore, the model needs to be simple and accurately predict the conversion of NO x . The reduction of NO is described by a global reaction, with a molar stoichiometry between NO, NH 3 and H 2 of 1:1:2. Further reactions included in the model are the oxidation of NH 3 to N 2 and NO, oxidation of H 2 , and the adsorption and desorption of NH 3 . The model was fitted to the results of an NH 3 ‐TPD experiment, an NH 3 oxidation experiment, and a series of H 2 ‐assisted NH 3 ‐SCR steady‐state experiments. The model predicts the conversion of NO x well even during transient experiments. © 2013 American Institute of Chemical Engineers AIChE J , 59: 4325–4333, 2013