Eu3+-> Eu2+ and Ce4+-> Ce3+ reduction in Au/Ce0.80Eu0.20O2 catalyst were systematically studied using in-situ NAP-XPS technique. The reduction of Eu3+-> Eu2+ in the ceria, in a hydrogen atmosphere at temperature >= 400 degrees C, has been demonstrated for the first time.
The effect of the reduction of Ce0.80Eu0.20O2 support on the catalytic activity of Au nanoparticles in CO oxidation has been investigated.