“…The other is a two-step mechanism called in situ or ''internal" selective catalytic reduction (iSCR), which involves the oxidation of a significant percentage of NH 3 into NO x species, and the NO x species subsequently react with NH 3 to form N 2 [9][10][11]. Many noble metal catalysts, such as Ag (powder), Pt, Pt/Al 2 O 3 , Rh/Al 2 O 3 , Pd/Al 2 O 3 , Pt-ZSM-5, Pd-ZSM-5, and Rh-ZSM-5, have been suggested to follow this iSCR route [9][10][11].…”