Synthesis and Oxygen Storage Capacities of Yttrium-Doped CeO(2) with a Cubic Fluorite Structure

Doping CeO(2) with Y cations was achieved in this study using three strategies: doping only during the hydrothermal process (H-Y-doped CeO(2)), doping only during the impregnation process (I-Y-doped CeO(2)), and doping during both the hydrothermal and impregnation processes (H/I-Y-doped CeO(2)). During the three synthesis strategies of Y-doped CeO(2), these Y ions could be incorporated into the CeO(2) lattice in the +3 state while holding the cubic fluorite structure, and no impurity phases were detected. Pure CeO(2) crystal itself contained a certain number of intrinsic V(O) defects, and Y-doping was beneficial for the creation of extrinsic V(O) defects. The relative concentrations of V(O) defects were quantified by the values of A(592)/A(464) obtained from Raman spectra, which were 1.47, 0.93, and 1.16 for the H-Y-, I-Y-, and H/I-Y-doped CeO(2), respectively, and were higher than that of the undoped one (0.67). Moreover, the OSCs of the three Y-doped CeO(2) were enhanced, and the sequence of OSCs was: H-Y-doped CeO(2) (0.372 mmol/g) > H/I-Y-doped CeO(2) (0.353 mmol/g) > I-Y-doped CeO(2) (0.248 mmol/g) > Undoped CeO(2) (0.153 mmol/g); this result was in good agreement with the Raman spectroscopy results.