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

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. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

By studying the CO oxidation catalyzed by CeO2-CuO/Cu2O nanocomposites with different CuO structures, it was found that the CuO-CeO2 interfaces in the CeO2-CuO/c-Cu2O (cubes) nanocomposites exhibit higher intrinsic activity, indicating that the active oxygen species originates from CuO. An active 13.2% CeO2-CuO/c-Cu2O(s) catalyst for CO oxidation was achieved on fine Cu2O cubes, possessing a high density of active sites.