CuO nanoparticles supported by ceria for NOx-assisted soot oxidation: insight into catalytic activity and sintering.

The current work introduces Cu nanoparticles (Cu-NPs) stabilized by organosilane and deposited as CuO-NPs onto ceria with two different morphologies: spongy, microstructured ceria synthesized by Solution Combustion (CeO 2 -SCS) and nanostructured ceria nanocubes (CeO 2 -NC). Catalytic activity tests have demonstrated that combination of CuO-NPs and CeO 2 -SCS bring significance to CO and NO oxidations as it results in easier reducibility and better metal dispersion on the surface. However, CuO-NPs with CeO 2 -NC give the opposite effect on CO and NO oxidations: the increase of Cu loading lowers the catalytic activity. However, Cu/CeO 2 -NC combination, especially the one with low Cu loading, gives the best synergy for normal soot oxidation with oxygen, thanks to the structure-sensitivity of the reaction. In the presence of NO x , Cu/CeO 2 -SCS catalysts are active for soot oxidation at low temperature as the catalysts favor early NO 2 formation. Lastly, a series of repeated tests with NO x -assisted soot oxidation was carried out to confirm that CuO-NPs suffer easily from particle sintering, possibly via migration and coalescence. [ABSTRACT FROM AUTHOR]