EFFECT OF SURFACE-AREA ON CO OXIDATION BY THE PEROVSKITE CATALYSTS LA1-XSRXMO3-DELTA (M = CO, CR)

The catalytic oxidation of carbon monoxide by two compounds in the sys tem La0.8Sr0.2MO3-delta (M = Co, Cr) was measured at different BET sur face areas of the oxide materials. The light-off temperature was found to decrease with increasing surface area up to a certain level beyond which it remained constant for the cobalt-containing compound. This l imiting value could not be attained for the chromium-containing compou nd because of equilibration problems in the preparation. As the active catalytic area as distinct from the total (BET) catalyst area was not clarified, these preliminary results show the need for further inquir y.