ENHANCED OXYGEN STORAGE CAPACITY OF CERIUM OXIDES IN CEO2/LA2O3/AL2O3 CONTAINING PRECIOUS METALS

Effects of the addition of precious metals (PM; Pt, Rh) on CeO2/Al2O3 and CeO2/La2O3/Al2O3 were confirmed to enhance the oxygen storage capacities (OSC). Increments in the OSC of the added CeO2/La2O3/Al2O3 catalysts were much greater than those in the OSC of the PM added CeO2/Al2O3. The enhanced OSC is ascribed to the interaction between PM and a CeO2-La2O3 solid solution formed during the catalyst preparation. No enhancements in the OSC were observed on physical mixing of CeO2/La2O3/Al2O3 and Pt-Rh/Al2O3, although the composition ratio of PM:CeO2:La2O3 is the same as that in the PM added CeO2/La2O3/Al2O3. This indicates that the intimate contacts between the precious metals and CeO2 particles dispersed on Al2O3 are essential for the enhanced OSC of cerium oxides. © 1990 American Chemical Society.