Synergistic effect of Cu and Ag on porous (Cu, Ag) co-doped CeO2 nanosheets for low-temperature CO oxidation

CeO2 with porous nanosheet structure was prepared by changing the calcination environment. The prepared CeO2 nanosheets had high specific surface area and porosity, which was suitable for supporting other active components. By the same synthesis conditions, a small amount of Cu and Ag was introduced into the synthesis system of CeO2 nanosheets respectively. The introduction of Cu or Ag did not significantly change the morphology of the prepared CeO2 nanosheets, but it notably improved the catalytic activity for CO oxidation. Therefore, considering the significant improvement of catalytic performance caused by the single doping of Cu or Ag, (Cu, Ag) were co-doped into the CeO2 system. The analysis of physical structure (XRD, BET, SEM and TEM) and surface chemical properties (XPS, Raman and H-2-TPR) showed that the (Cu, Ag) co-doping not only improved the dispersion of Cu and Ag species on the catalyst surface, but also increased the Ag0 and oxygen vacancies on the catalyst surface. The smaller Ag-0 crystallite size and the abundant oxygen vacancies made the catalyst easier to activate O-2 at low temperature, so the activity of the catalyst at low temperature was significantly enhanced compared to the CeO2 singly doped with Cu or Ag. At the same time, the high dispersion of CuAg species was conducive to electron transfer between Cu-Ag species and CeO2 support.