The key role of highly dispersed rhodium in the chemistry of hydrogen-ceria systems

In the presence of rhodium, the H2–CeO2 interaction is to a large extent reversible, simple evacuation of the reduced sample has been demonstrated to promote reoxidation of the support; this explains some puzzling effects of the reduction/evacuation treatments on the actual oxidation state of ceria in Rh–CeO2 catalysts.