An exploration of soot oxidation over CeO2-ZrO2 nanocubes: Do more surface oxygen vacancies benefit the reaction?

Abstract CeO 2 , Ce 20 Zr 1 and Ce 10 Zr 1 mixed oxides with uniform nanocubic morphology and varied amounts of surface oxygen vacancies were synthesized to study the influence of surface oxygen vacancies on soot catalytic oxidation in a low concentration of gaseous O 2 . It is presented that excessive surface oxygen vacancies may lead to low soot oxidation activity and catalyst deactivation during the reaction. H 2 -TPR results indicate that the doping of Zr does not decrease the amount of surface redox sites. Instead, it induces the formation of surface capping oxygen (O 2− ) rather than the highly active O x − species, which hereby affects the catalyst behavior significantly. These point out that a ceria-based catalyst should not contain too many surface oxygen vacancies when designing for the application in gasoline particulate filters.