Fe-doped ceria solids synthesized by the microemulsion method for CO oxidation reactions

Abstract

A series of Ce-Fe mixed oxides as well as the pure oxides were synthesized by the microemulsions method. The solid solution formation was established for all the Fedoped systems and only a hardly noticeable segregation of α-Fe 2 O 3 was appreciated for the solid with the maximum iron content (50 Fe atomic%). The oxygen exchange is improved for all the Fe-doped systems; however the 10 Fe atomic% appears as the optimal iron content for achieving the maximum oxygen vacancies concentration and the higher reducibility efficiency. The CO oxidation (TOX, PROX) is especially achieved for the solids with the lower iron contents but with a superior oxygen vacancies proportion. These Ce-Fe systems prepared from microemulsions are very attractive to be considered as supports for depositing active phases capable of enhancing oxygen exchange ability of the whole system, allowing higher CO oxidation abilities.

Synergy between gold and oxygen vacancies in gold supported on Zr-doped ceria catalysts for the CO oxidation

“…In good agreement with our results, the enhancement of the catalytic activity in CO oxidation reactions by doping the structure of CeO 2 has been widely evidenced by many authors applying several doping agents: Zn [63], Sm [22], Fe [64], Co, Mn [65], Cu [66,67] and Eu [43], among others. In these works, the creation of oxygen vacancies by the strong interaction of the CeO 2 framework and the doping cation is commonly proposed as a determinant structural effect that facilitates the adsorption and activation of the CO and O 2 molecules during the catalytic reaction.…”

Gold supported on CuOx/CeO2 catalyst for the purification of hydrogen by the CO preferential oxidation reaction (PROX)

“…The tetragonalization of the cubic structure by the presence of Ce 3+ species may be confirmed by the broad and small signal centered at 279 cm -1 [51]. The promotion of the oxygen vacancies population by the inclusion of copper species is in good agreement with that widely established by different authors whose demonstrated that the doping of the cerium oxide results in the promotion of oxygen vacancies [14,37,40,52].…”

Enhanced Catalytic Activity of Supported Gold Catalysts for Oxidation of Noxious Environmental Pollutant CO

“…In particular, this band is correlated with the presence of the oxygen vacancies (O v ) and/or lattice defects (MO 8 -type complex defects). The defective structure is associated with relative amount of Ce 3+ ions, preferentially placed on the surface of the sample that could be enhanced when dopant enters the lattice of cerium oxide [17,30,31]. It is evident from Figure 2(b) that incorporation of Zr 4+ cation into the cubic fluorite lattice of ceria results in broadening of F 2g band and is blue shifted towards higher wave numbers.…”