Effect of ageing on the behavior of Ce in three- way catalysts

IRUSTA, SILVIA; BOIX, ALICIA V.; VASALLO, JULIO; MIRÓ, EDUARDO E.; PETUNCHI, JUAN

STUDIES IN SURFACE SCIENCE AND CATALYSIS

Elsevier Science B. V

Lugar: Amsterdam; Año: 1998 vol. 116 p. 175 - 184

0167-2991

The Environmental Protection Agency requires that on-board diagnostic (OBD-II) be used to monitor the hydrocarbon conversion efficiency of the catalytic converter. The current method is the dual oxygen sensor where a comparison of the responses of front and rear sensors is a measure of the oxygen storage capacity of the catalytic converter. Since the amount of oxygen storage in the three-way catalysts correlates with the Ce content in the catalysts, the goal of this work is to carried out a systematic study of the volumetric and surface redox properties of Ce on three-way catalysts by TPR and XPS. Studies were also made to determine how these properties were affected by thermal aging and the use of the catalysts in automobile for 50,000 Km. The effect of promoters such as La, Ba and Sr on the same properties is also analyzed. The redox capacity is correlated with the catalytic activity obtained with synthetic mixtures.