Understanding improved thermal stability of lanthanum-modified Cu/CeO₂-ZrO₂ for CO oxidation under lean-burn exhaust conditions

Rigorous emission regulations and the advancements in combustion engines have forced researchers to develop new strategies for removing CO at low temperatures. The Cu/CeO₂-ZrO₂ (Cu/CZ) catalyst has received an extensive attention due to its low cost and high CO oxidation activity at low temperatures. Nonetheless, the poor thermal stability of Cu/CZ remains as a major challenge for practical applications. In this study, we systematically investigated the effect of La doping on the hydrothermal stability of Cu/CZ. The La-doped catalyst, Cu/CZL, retained a high CO oxidation ability even after thermal aging at 800 °C for 20 h. La doping not only helped preserve the surface-active oxygen and oxygen storage capacity of Cu/CZ during thermal aging, but also enhanced its ability to efficiently convert intermediate surface carbonate species into CO₂. These promoting effects of La resulted in the excellent CO oxidation activity over the aged-Cu/CZL under the simulated exhaust condition, significantly outperforming the conventional counterpart, PtPd/γ-Al₂O₃.