Fe-doped ceria nanopowders synthesized by freeze-drying precursor method for electrocatalytic applications

Formation of La1−xSrxCo1−yFeyO3−δ cathode materials from precursor salts by heating in contact with CGO electrolyte

“…Although, perovskite phase is obtained for both 6428 and 5555; both samples failed to produce the relevant LSCF compounds because of uneven diffusion of La, Sr, Co and Fe into the substrate which disturbed the stoichiometry. Similar observation was also made in the literature [34]. The number of salt mixture combinations that were heated, cut and SEM-analysed was thirteen but only three of them are given here for Fig.…”

Formation of Catalytic Active Sites in Hydrothermally Obtained Binary Ceria–Iron Oxides: Composition and Preparation Effects

“…The observed shrinkage of the lattice parameters is generally attributed to the replacement of larger Ce 4+ ions (0.101 nm: ionic radius for 6-coordinate, octahedral) by smaller Fe 3+ ones (0.069 nm: ionic radius for 6coordinate, octahedral). 16,18,25,28,31 This tendency was well pronounced (Figure S1) almost in the whole concentration region (up to Fe/Ce 8:2), which evidenced the permanent increase of the solubility of Fe 3+ ions in the ceria lattice. In addition, the appearance of reflections at 24.…”

“…Recently, several reports on the successful synthesis of Fedoped ceria materials with different composition by costeffective methods have been published. 16−18,28,36−41 Mazan et al 25 temperatures up to 623 K. Li et al 30 reported similar results by the application of a hydrothermal approach at 473 K. Laguna et al 21 observed facile dissolution of 25% Fe in ceria using a microemulsion preparation procedure. Bao et al 8 found a limit for the Fe 2 O 3 −CeO 2 solid solution around 30 mol % Fe using co-precipitation with urea and calcination at 923 K. Peŕez-Alonso et al 39 synthesized solid solution with 50% Fe content without segregation of pure oxides by co-precipitation with NH 4 OH and calcination at 573 K. They reported segregation of hematite particles when the temperature increased up to 773 K. The significant impact of the calcination temperature on the iron solubility in ceria was also demonstrated in the literature.…”

“…In addition, the appearance of reflections at 24. 2,25,26 The observed increase in the hematite lattice parameters with the increase of ceria content in the samples revealed that the hematite phase was partially substituted with Ce 4+ (Table 1). Note that the variations in the hematite and ceria lattice parameters did not simply follow Vegard's law, 30,36 especially in the moderate Fe/ Ce composition, which proposed a more complex mechanism of the formation of the solid phase (Figure S1).…”

“…This indicated simultaneous improvement in the reduction ability of both iron and ceria components in the sample. 11,25,27,28,31 For the samples with low iron content, Li et al 5 also observed overlapping of the two low-temperature (LT) peaks. The observed effect was assigned to simultaneous reduction of Fe 3+ and Ce 4+ ions in the solid solution and to the segregated Fe 2 O 3 particles.…”