Search

Rigorous emission regulations and the advancements in combustion engines have forced researchers to develop new strategies for removing CO at low temperatures. The Cu/CeO 2 -ZrO 2 (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 CO 2. 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-Al 2 O 3. [Display omitted] • La greatly enhanced the thermal stability of Cu/CeZrO 2 in CO oxidation. • Cu/CeZrLaO 2 outperformed PtPd/Al 2 O 3 under simulated lean-burn exhaust conditions. • La maintained the surface-active oxygen and OSC of Cu/CeZrO 2 catalyst. • The active oxygen sites promoted the decomposition of surface carbonate species. [ABSTRACT FROM AUTHOR]

Single-crystal nanocrystals of catalytic metals and oxides are essential for understanding chemical interactions on well-defined catalyst surfaces. However, a comprehensive understanding of the crystallographic origins for such enhancement has been lacking. This work provides formal evidence of the structure–property relationship through a model study on single-crystal TiO 2. Our approach involves transient pulse heating to manipulate porosity and phase in epitaxially-grown TiO 2 nanosheets along the (0 0 1) plane. Furthermore, we could introduce high-entropy alloy nanoparticles into the system, which exhibited excellent catalytic activity toward CO oxidation, achieving T 90 at 143 °C. This improved performance is attributed to the interplay between the catalytic nanoparticles and the multiphase support, facilitating CO and O 2 adsorption. Our study contributes to a fundamental understanding of structure–property relationships in heterogeneous catalyst systems. Overall, our thermal shock synthesis approach shows much promise for developing single crystal-based advanced nanocatalysts with broad practical implications. [ABSTRACT FROM AUTHOR]

The influence of iron oxide, FeO x , on Pt for CO oxidation was investigated. A film of FeO x , nominally 0.8-nm thick, was added to a Pt/Al 2 O 3 catalyst by Atomic Layer Deposition. The film was found to wet the Pt surface after oxidation at 773 K and 973 K, as shown by aberration-corrected, transmission electron microscopy. In-situ infrared spectra and CO chemisorption measurements showed that the addition of the FeO x greatly suppressed CO adsorption but enhanced CO oxidation rates due to FeO x -Pt interfaces. The FeO x layer also improved the stability of the catalyst by mitigating the sintering of Pt particles at 973 K. • Atomic-scale FeO x overlayer augments the CO oxidation activity and thermal stability of the Pt/Al 2 O 3 at 973 K. • TEM and CO chemisorption shows that FeO x overlayer wets the Pt surface and greatly suppresses CO adsorption on Pt. • In-situ infrared spectra shows that CO oxidation occurs without CO adsorption on FeO x -overcoated Pt catalyst. • FeO x overlayers near Pt enhances CO oxidation rates through the FeO x -Pt interfaces. [ABSTRACT FROM AUTHOR]