Ce 0.9 (mg,ni) 0.1 O 2 : Composite or Solid Solution

Samples of the composition Ce 0.9 (Mg 1 – x Ni x ) 0.1 O 2 (0 ≤ x ≤ 1, step x = 0.1) have been obtained by gel combustion followed by hydrothermal treatment. X-ray powder diffraction data have showed that after gel combustion and annealing at 1100°C, composite CeO 2 (fluorite structure)/solid solution Mg 1 – x Ni x O (halite structure) is formed, and additional hydrothermal treatment followed by annealing promotes the formation of limited solid solution Ce 0.9 (Mg 1 – x Ni x ) 0.1 O 2 . According to the results of IR spectroscopy, the CeO 2 /Mg 1 – x Ni x O composite does not adsorb CO 2 even in the presence of water vapor, which is also confirmed by diffuse reflectance spectra in the UV-visible region. On the contrary, the Ce 0.9 (Mg 1 – x Ni x ) 0.1 O 2 solid solution absorbs CO 2 , as evidenced by the results of IR spectroscopy and thermogravimetric analysis.