Study of the "Fast SCR"-like mechanism of H2-assisted SCR of NOx with ammonia over Ag/Al2O3

Authors
Dmitry E. Doronkin,
Sebastian Fogel,
Stefanie Tamm,
Louise Olsson,
Tuhin Suvra Khan,
Thomas Bligaard,
Pär Gabrielsson,
Søren Dahl
Year of publication
2012
Journal
Applied Catalysis B: Environmental
Volume
113-114
Starting page
228
Ending page
236
It is shown that Ag/Al2 O3 is a unique catalytic system for H2 -assisted selective catalytic reduction of NOx by NH3 (NH3-SCR) with both Ag and alumina being necessary components of the catalyst. The ability of Ag/Al2O3 and pure Al2O3 to catalyse SCR of mixtures of NO and NO2 by ammonia is demonstrated, the surface species occurring discussed, and a “Fast SCR”-like mechanism of the process is proposed. The possibility of catalyst surface blocking by adsorbed NOx and the influence of hydrogen on desorption of NOx were evaluated by FTIR and DFT calculations.
Keywords
ag/al2o3; alumina; nox scr; fast scr; ftir; selective catalytic-reduction; silver-alumina catalyst; nitric-oxide; hydrogen storage; lean conditions; gamma-alumina; adsorption; h-2; o-2; hydrocarbons