Optimization of Ce0.6Zr0.4−x Al1.3x O2 solid solution based on oxygen storage capacity

Improvement of Air/Fuel Ratio Operating Window and Hydrothermal Stability for Pd-Only Three-Way Catalysts through a Pd–Ce2Zr2O8 Superstructure Interaction

“…The XRD patterns of Pd/50CZA-f, Pd/50CZA-a, and Pd/50CZA-ro (Figure a) show that no Pd species were detected because of either the high dispersion or the overlap of the diffraction peaks with those features of the tetragonal Ce 0.5 Zr 0.5 O 2 (JCDPS 38-1436) phase . Additionally, weak features due to the γ-Al 2 O 3 (JCDPS04-0880) phase were observed, which limited the degradation of surface areas, as mentioned above. , However, the CeAlO 3 phase, a species that has no reducibility, , was never present, confirming that 50% Al 2 O 3 in CZA is optimum from the perspective of Al 2 O 3 and CZ interactions . XRD results are consistent with STM elemental mapping taking Pd/50CZA-ro as an example, which shows Pd dispersed over the CZ and Al 2 O 3 (Figure b1).…”

“…27 Additionally, weak features due to the γ-Al 2 O 3 (JCDPS04-0880) phase were observed, which limited the degradation of surface areas, as mentioned above. 3,4 However, the CeAlO 3 phase, a species that has no reducibility, 19,26 was never present, confirming that 50% Al 2 O 3 in CZA is optimum from the perspective of Al 2 O 3 and CZ interactions. 3 XRD results are consistent with STM elemental mapping taking Pd/50CZA-ro as an example, which shows Pd dispersed over the CZ and Al 2 O 3 ( Figure 2b1).…”

“…One is doping with other metal ions. The composite oxide of Al 2 O 3 and CZ (CZA) has been practically applied in TWCs as OSC materials since 2001. , The higher OSC is contributed to the so-called “diffusion barrier” of Al 2 O 3 . The other approach is redox (ro) treatment composed of high-temperature reduction treatment (e.g., > 900 °C in H 2 atmosphere) with a mild-temperature reoxidation (e.g., 500–650 °C). , The promoted OSC for CZ after ro-treatment (CZ-ro) is related to the presence of the cubic, fully oxidized, pyrochlore-like superstructure, Ce 2 Zr 2 O 8 . ,− …”

“…The composite oxide of Al 2 O 3 and CZ (CZA) has been practically applied in TWCs as OSC materials since 2001. 3,4 The higher OSC is contributed to the so-called "diffusion barrier" of Al 2 O 3 . The other approach is redox (ro) treatment composed of high-temperature reduction treatment (e.g., > 900 °C in H 2 atmosphere) with a mild-temperature reoxidation (e.g., 500−650 °C).…”

Recent advances in gasoline three-way catalyst formulation: A review

“…13,24 Priya et al 25 find that Ce 0.6 Zr 0.4 O 2 has the highest OSC, while Madier et al 26 report that Ce 0.63 Zr 0.37 O 2 has the highest OSC. In a more complex mixed oxide experiment, Priya et al 27 also synthesized a series of Ce 0.6 Zr (0.4–x) Al 1.3x O 2 oxides (x = 0, 0.1, 0.2, 0.3, and 0.4), finding that Ce 0.6 Zr 0.2 Al 0.26 O 2 had the highest OSC. However, such materials can undergo phase separation into separate Ce-rich and Zr-rich particles at high temperatures.…”