Abstract
A quasi in situ X-ray absorption study demonstrated that the disproportionation of hydrogen peroxide (H 2 O 2 ) promoted by ceria nanorods was associated with a reversible Ce 3+ /Ce 4+ reaction and structural transformations in ceria. The direction of this reversible reaction was postulated to depend on the H 2 O 2 concentration and the fraction of Ce 3+ species in ceria nanorods.