Controlled synthesis of nanocrystalline CeO2 and Ce1−xMxO2−δ (M=Zr, Y, Ti, Pr and Fe) solid solutions by the hydrothermal method: Structure and oxygen storage capacity

CeO2 and Ce1−xMxO2−δ (M=Zr, Ti, Pr, Y and Fe) nanocrystallites of 5–10 nm sizes have been synthesized by hydrothermal method using diethylenetriamine (DETA) and melamine as complexing agents. Compounds have been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray analysis (EDX) and their structures have been refined by the Rietveld method. All the compounds crystallize in cubic fluorite structure. Even up to 50% Zr and Y, 40% Ti, 25% Pr and 15% Fe is substituted for Ce4+ in CeO2 by this method. Sizes of crystallites can be tuned by changing the complexing agent and reaction temperature. Nanocrystalline CeO2 and Ce1−xZrxO2 prepared here have higher or at least competitive oxygen storage capacity (OSC) than those reported in literature. Ce1−xFexO2−δ shows higher OSC and higher percentage of CO oxidation at lower temperature than Ce1−xZrxO2.

Graphical abstractCeO2 and Ce1−xMxO2−δ (M=Zr, Ti, Pr, Y and Fe) nanocrystallites of 5–10 nm sizes have been synthesized by hydrothermal method using diethylenetriamine (DETA) and melamine as complexing agents. Ce1−xFexO2−δ shows higher OSC and higher percentage of CO oxidation at lower temperature than Ce1−xZrxO2. CO conversion with lattice oxygen from (a) CeO2 (5 nm), (b) Ce0.75Zr0.25O2, (c) Ce0.50Zr0.50O2 and (d) Ce0.85Fe0.15O1.85.Figure optionsDownload full-size imageDownload as PowerPoint slide