CuxCe1-xO2 nanoflakes with improved catalytic activity and thermal stability for diesel soot combustion

In the present study, nanoflakes (NF) of CeO2-NF and CuxCe1-xO2-NF (x = 0.1, 0.2, 0.3 and 0.4) were prepared with the polyvinylpyrrolidone(PVP)-assisted co-precipitation method. The prepared samples were characterized with FE-SEM, HR-TEM, XRD, N-2 adsorption, O-2-TPD, H-2-TPR, Raman and XPS. It was found that doping of Cu in CeO2-NF significantly promoted the formation of oxygen species that replenished the vacancies. The CuxCe1-xO2-NF exhibited much better activity than CeO2-NF that has no Cu doping both in tight contact and NO-assistant loose contact modes. The highest activity was observed for the sample of Cu0.2Ce0.8O2-NF, which was most likely caused by its moderate doping that induced both a large amount of surface adsorbed oxygen species and a special flake morphology, thus providing effective contact area. Both the cyclic and accelerated aging tests demonstrated that Cu0.2Ce0.8O2-NF was able to keep a good thermal stability.