H2 dissociation over Ag/Al2O3: the first step in hydrogen assisted selective catalytic reduction of NOx

Hydrogen assisted selective catalytic reduction of NOx over Ag/Al2O3 with either hydrocarbons or ammonia as reducing agents is an emerging technology for lean NOx reduction. Herein, we present a density functional theory study of H-2 dissociation over a representative set of sites present on the Ag/Al2O3 catalyst. Whereas H-2 dissociation over supported Ag ions and oxidized Ag surfaces is found to be facile, dissociation over metallic Ag, defect free Al2O3 and alumina-supported Ag is associated with high barriers. The results are rationalized by analysis of the electronic structure.