EPR simulation to confirm the formation of Ag6O5 complex on the surface of 10% Ag/CeO2 catalyst after the propylene oxidation reaction

Abstract

Ag2+(b) species were detected by electron paramagnetic resonance (EPR) on silver loaded over ceria by impregnation in a previous work. Contrasting the EPR simulation with the experimental measurements evidenced that, upon propene oxidation, the Ag2+(b) species transform into two clusters each containing 2 Ag2+ and 1 Ag+ species. This cluster is composed of two parallel electron spins (dimer) and three nuclear spins (trimer). Such a result led us to suggest that initially, Ag2+(b) species clusters were formed by three parallel electron spins. The ferromagnetic character of Ag2+(b) species may explain their catalytic performance towards total oxidation of propylene.