Activation and deactivation of Ag/CeO₂ during soot oxidation: influences of interfacial ceria reduction

Abstract

Both the existence of CeO2 surface oxygen vacancies and their dynamic change during reaction may cause crucial influence on the soot oxidation behavior of Ag/CeO2.

Lattice oxygen activity in ceria-praseodymia mixed oxides for soot oxidation in catalysed Gasoline Particle Filters

“…10), thus suggesting that other factors can play a role under these reactions conditions. In line with the findings reported by Liu and co-workers [41,42], and taking into consideration the poor contact conditions achieved in the loose contact mode, the possible influence of the presence and distribution of large mesopores, that could be critical under the starting situation of the low dispersion of soot particles onto the catalyts' surfaces, (see Fig. S2) is tentatively proposed as one feature to take into account.…”

Soot Oxidation over CeO2 or Ag/CeO2: Influences of Bulk Oxygen Vacancies and Surface Oxygen Vacancies on Activity and Stability of the Catalyst

“…The lower oxygen content and almost no NO x in GDI exhausts make the commercial catalyst, Pt, quite ineffective for removing soot in diesel exhausts . On the basis of some previous studies, CeO 2 and Ag/CeO 2 are considered as promising catalysts in diesel exhausts, and are comparable to the commercial catalyst Pt.…”

Ag/CeO2 Composites for Catalytic Abatement of CO, Soot and VOCs

“…Based on the results of the ESR experiments, a mechanism for the observed phenomenon was proposed, in which a superoxide ion (O2 − ) generated on the catalyst surface first migrated to the ash surface and then to the soot particles and then subsequently oxidizes it. In [112] several model Ag/CeO2 catalysts with uniform structures and diverse surface oxygen vacancy (VO-s) contents were prepared by solution combustion method, and the processes of their activation and deactivation were considered ( Figure 13). The VO-s content, conditions of catalyst-soot contact and extra oxygen supplier were pointed out as the most important structural factors in the activity of soot oxidation catalysts.…”

“…Reproduced from Ref [104]. with the permission from the Elsevier.In[112] several model Ag/CeO 2 catalysts with uniform structures and diverse surface oxygen vacancy (V O-s ) contents were prepared by solution combustion method, and the processes of their activation and deactivation were considered (Figure 13). The V O-s content, conditions of catalyst-soot contact and extra oxygen supplier were pointed out as the most important structural factors in the activity of soot oxidation catalysts.…”

“…Schematic explanation for activity variations over (a) Ag/CeO 2 with low initial V O-s concentration (e.g., AgCe-0, AgCe-0.01, AgCe-0.02 and AgCe-0.03) and (b) Ag/CeO 2 with high initial V O-s concentration (e.g., AgCe-0.04 and AgCe-0.05) during isothermal soot oxidation. Reproduced from Ref [112]. with the permission from the Royal Society of Chemistry.…”