n this study, a series of conventional polycrystalline ceria and single-crystalline ceria nanorods and nanocubes were prepared by hydrothermal methods, and their structural, redo; and morphological properties were investigated using XRD, SEM, HRTEM, BET, temperature-programmed reduction, and oxygen storage capacity measurements. According to HRTEM, they are characterized by exposure of different surfaces: {100} surface for nanocubes; {100}, {110}, and in part {111} for nanorods; and mainly {1 1 1} for conventional polycrystalline ceria, with a morphology dominated by {111}-enclosed octahedral particles. The presence of more-reactive exposed surfaces affects the reaction of soot oxidation positively, with an increase in activity in nanoshaped materials compared with conventional ceria. Thermal aging, although detrimental for surface area, is shown to affect morphology by promoting irregular truncation of edges and corners and development of more reactive surface combinations in all crystal shapes. It is likely that thermal treatment, starting from either cubes or octahedral particles, induces the formation of a similar particle geometry whose activity is dependent on the type of plane exposed and by the number an extension of edge and corners, thus linking reactivity of octahedral particles in conventional ceria powders with that of cubes in nanoshaped materials. The results indicate that soot oxidation is also a surface-dependent reaction, and catalyst design for this purpose should allow for surface structure morphology and its evolution against temperature.

Shape-dependent activity of ceria in soot combustion

ANEGGI, Eleonora;WIATER, Dawid;DE LEITENBURG, Carla;TROVARELLI, Alessandro
2014

Abstract

n this study, a series of conventional polycrystalline ceria and single-crystalline ceria nanorods and nanocubes were prepared by hydrothermal methods, and their structural, redo; and morphological properties were investigated using XRD, SEM, HRTEM, BET, temperature-programmed reduction, and oxygen storage capacity measurements. According to HRTEM, they are characterized by exposure of different surfaces: {100} surface for nanocubes; {100}, {110}, and in part {111} for nanorods; and mainly {1 1 1} for conventional polycrystalline ceria, with a morphology dominated by {111}-enclosed octahedral particles. The presence of more-reactive exposed surfaces affects the reaction of soot oxidation positively, with an increase in activity in nanoshaped materials compared with conventional ceria. Thermal aging, although detrimental for surface area, is shown to affect morphology by promoting irregular truncation of edges and corners and development of more reactive surface combinations in all crystal shapes. It is likely that thermal treatment, starting from either cubes or octahedral particles, induces the formation of a similar particle geometry whose activity is dependent on the type of plane exposed and by the number an extension of edge and corners, thus linking reactivity of octahedral particles in conventional ceria powders with that of cubes in nanoshaped materials. The results indicate that soot oxidation is also a surface-dependent reaction, and catalyst design for this purpose should allow for surface structure morphology and its evolution against temperature.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11390/1070137
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 327
  • ???jsp.display-item.citation.isi??? 316
social impact