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

Several CeO 2 -CuO/Cu 2 O nanocomposites with different CuO structures were used to identify the structure sensitivity of CuO in the CeO 2 -CuO/Cu 2 O catalyzed CO oxidation. The CO oxidation catalyzed by various CuO-CeO 2 interfacial sites involves a typical Mars-van Krevelen mechanism, in which the CuO-CeO 2 interfaces in the CeO 2 -CuO/c-Cu 2 O (cubes) nanocomposites are more intrinsically active, exhibiting ca. 15 kJ mol −1 lower activation energy than those in the CeO 2 -CuO/o-Cu 2 O (octahedra) and CeO 2 -CuO/d-Cu 2 O (rhombic dodecahedra) nanocomposites at CeO 2 loadings no less than 0.75 wt%. The higher activity is relevant to lower coordinated oxygen ions on CuO/c-Cu 2 O surface and thus better CO reactivity for the CeO 2 -CuO/c-Cu 2 O nanocomposites, which therefore indicates that the active oxygen species on CuO-CeO 2 interface should come from CuO rather than CeO 2 . Moreover, a highly active 13.2 %CeO 2 -CuO/c-Cu 2 O(s) catalyst for CO oxidation is realized on fine Cu 2 O cubes, which thus has high density of active sites.