Structure sensitivity of CuO in CO oxidation over CeO2-CuO/Cu2O catalysts

• Published in: Journal of catalysis Vol. 405; pp. 333 - 345
• Main Authors: Zhang, Zhenhua, Fan, Liping, Liao, Weiqi, Zhao, Feiyue, Tang, Cen, Zhang, Jing, Feng, Ming, Lu, Ji-Qing
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.01.2022
• Subjects: Active structure; CeO2-CuO/Cu2O; CO oxidation; Structure sensitivity; Surface restructuring; Active structure; CeO2-CuO/Cu2O; Structure sensitivity; CO oxidation; Surface restructuring
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2021.12.015

[Display omitted] •The CO oxidation catalyzed by various CuO-CeO2 interfacial sites involves a typical Mars-van Krevelen mechanism.•The CuO-CeO2 interfaces in the CeO2-CuO/c-Cu2O (cubes) nanocomposites are more intrinsically active at CeO2 loadings no less than 0.75 wt%.•The higher activity is relevant to lower coordinated oxygen ions and thus better CO reactivity for the CeO2-CuO/c-Cu2O nanocomposites.•The active oxygen species on CuO-CeO2 interface in catalyzing CO oxidation should come from CuO rather than CeO2.•A highly active 13.2 %CeO2-CuO/c-Cu2O(s) (small) catalyst with high density of active sites for CO oxidation is realized on fine Cu2O cubes. Several CeO2-CuO/Cu2O nanocomposites with different CuO structures were used to identify the structure sensitivity of CuO in the CeO2-CuO/Cu2O catalyzed CO oxidation. The CO oxidation catalyzed by various CuO-CeO2 interfacial sites involves a typical Mars-van Krevelen mechanism, in which the CuO-CeO2 interfaces in the CeO2-CuO/c-Cu2O (cubes) nanocomposites are more intrinsically active, exhibiting ca. 15 kJ mol−1 lower activation energy than those in the CeO2-CuO/o-Cu2O (octahedra) and CeO2-CuO/d-Cu2O (rhombic dodecahedra) nanocomposites at CeO2 loadings no less than 0.75 wt%. The higher activity is relevant to lower coordinated oxygen ions on CuO/c-Cu2O surface and thus better CO reactivity for the CeO2-CuO/c-Cu2O nanocomposites, which therefore indicates that the active oxygen species on CuO-CeO2 interface should come from CuO rather than CeO2. Moreover, a highly active 13.2 %CeO2-CuO/c-Cu2O(s) catalyst for CO oxidation is realized on fine Cu2O cubes, which thus has high density of active sites.