Surface active site of modified zeolites and zirconia in the conversion of nitrongen(I,II) oxides

Abstract

Samples of zirconia doped with transition metal (Cr, Co, Ce) oxides, and also rhodium-promoted and Fe-containing zeolites of different structural types, were studied by NH3-TPD and IR spectroscopy. The various samples were analyzed with respeet to their catalytic performances in deNOx reactions, in particular the selective catalytic reduction of NO (N2O) using hydrocarbons as reducing agents (HC SCR). Bifunctional zeolite- and ZrO2. based catalysts exhibited high activity in the SCR of nitrogen(I, II) oxides to dinitrogen due to the combination of the surface redox and acidic properties exhibited by these materials.