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. [Display omitted] •La greatly enhanced the thermal stability of Cu/CeZrO2 in CO oxidation.•Cu/CeZrLaO2 outperformed PtPd/Al2O3 under simulated lean-burn exhaust conditions.•La maintained the surface-active oxygen and OSC of Cu/CeZrO2 catalyst.•The active oxygen sites promoted the decomposition of surface carbonate species.