NO reduction with CH4 or CO on Pt/ZrO2-CeO2 catalysts

Catalytic properties of platinum supported on ZrO2-CeO2 were studied in the NO reduction by CO or CH4 as a reducing agent. The catalysts were characterized by means of N-2 adsorption, SEM, XRD, TPR and 2-propanol decomposition. Pt/CeO2 catalyst showed a higher surface area than the Pt/ZrO2-CeO2 and Pt/ZrO2 catalysts. All samples showed irregular shape and cumulus size. The PtO2 reduction causes spill over of hydrogen onto the support inducing a concurrent reduction of platinum oxide and the ceria-rich support. The monoclinic and tetragonal phases of the ZrO2 and the cubic phase of the CeO2 were identified in the catalysts. 2-Propanol reaction on ZrO2 sample showed high selectivity towards propene, this is due to the acid properties of this material. The reduction of the NO was dependent of the reducing agent on the catalysts. When CH4 was used for NO reduction, the catalysts that contain zirconia in the support showed the highest catalytic activity. The NO reduction with CO produced a shift to higher temperature, on this reaction the ceria-content catalysts showed the best catalytic activity. The highest selectivity toward N-2 was showed when CH4 was used as a reduction agent for the NO reduction. While, the highest N-2 yield was observed on Pt/ZrCe-70 catalysts for both reactions. (c) 2005 Elsevier B.V. All rights reserved.