PROPERTIES OF LACO1-TCRTO3 .3. CATALYTIC ACTIVITY FOR CO OXIDATION

The catalytic activity for CO oxidation has been studied for samples o f the solid-solution series LaCo1-tCrtO3, and NdCoO3 for comparison. T he catalytic activity over LaCo1-tCrtO3 generally decreases with incre asing chromium content. For samples with t = 0.70 and 0.80, distinct a ctivity changes occur during the reaction, for t = 0.80 representing a permanent deactivation. Samples of LaCo1-tCrtO3 were also studied by XRD, TPR, TG and XPS. Variations in catalytic activity were compared w ith variations in structural, physical and chemical properties. A roug h correlation was found between the starting temperature for reduction during TPR and the temperature required for 5% CO conversion. Further more, the activity pattern at 600 K follows the atom percentage of sur face oxygen species as seen by XPS. Possible surface reactions on LaCo 1-tCrtO3 during the catalytic oxidation of CO are discussed.