Enhanced hydrothermal stability and oxygen storage capacity of La3+ doped CeO2-γ-Al2O3 intergrowth mixed oxides

La3+-doped CeO2-γ-Al2O3 intergrowth mixed oxide powders were synthesized using an improved amorphous citric precursor (IACP) method and then steam-aged with 90% steam and 10% air for 12 h at 788 °C. The synthesized materials were characterized through X-ray diffraction, energy-dispersive X-ray spectrometry, H2 temperature programmed reduction, Brunauer–Emmett–Teller, and oxygen storage/release capacity (OSC) measurements. La3+ was successfully doped into the CeO2-γ-Al2O3 lattice to form an intergrowth system. Strong intergrowth interactions were observed between CeO2, La2O3, and γ-Al2O3 crystallites. The (Ce0.92La0.08)0.4Al0.6O2−z(CLA) sample showed a maximum OSC of 979 μmol g−1; however, the pure ceria sample showed a low OSC of 315 μmol g−1. The CLA samples maintained a relatively high OSC of 880 μmol g−1 even after hydrothermal treatment. These results may be attributed to the incorporation of La3+ ions into the ceria lattice to form a CeO2–La2O3 solid solution as well as to the intergrowth interactions between the CeO2–La2O3 solid solution and γ-Al2O3. Such interactions affected structural homogeneity and oxygen vacancy formation and inhibit the CLA particles from sintering during steam-aging.