A resonant photoemission applied to cerium oxide based nanocrystals

Cerium 4f level occupation determines the properties of cerium oxide based catalysts in a significant way. The Ce 4f level of nanosized cerium oxide particles was investigated with the use of resonant photoelectron spectroscopy in the Ce 4d-4f photoabsorption region. A stronginteraction of ceria with different additives. e.g. Pd and Sn, led to a partial Ce^4+(Rightwards double arrow) Ce3+ transition that was observed as a significant resonance enhancement of 4f photoemission intensity. Increases of the CO oxidation catalytic activity were observed simultaneously. Theratio of resonance enhancement of Ce photoemission intensity DCe^+3/ DCe^+4 was used to monitor Ce^+3 and Ce^4+ state occupation. The relative parameter DCe^3+/ DCe^4+ was found to be particularly useful in the case of photoemission studies of nanopowder ceria catalysts.