Study of the Co-Pt synergism for the selective catalytic reduction of NOx with CH4

The selective catalytic reduction of NOx with CH4 in excess oxygen with or without added water was conducted over a series of ion-exchanged mordenites . The fresh catalysts contained both Pt and Co cations in varying proportio ns. Different treatments of the solid either after or between exchanges wer e performed in order to learn about the beneficial effect of Pt added to Co -mordenite. Temperature-programmed reduction of the solids together with ph otoelectron spectroscopy provided information concerning the interaction, m igration, and oxidation states of Co and Pt. These studies were performed o ver the fresh, reduced, and used catalysts. The best formulations have Co/P t atomic ratios between 15 and 24 and they exhibit better water resistance than Co-mordenites. (C) 2001 Academic Press.