Novel Mn-Cu-Containing CeO Nanopolyhedra for the Oxidation of CO and Diesel Soot: Effect of Dopants on the Nanostructure and Catalytic Activity.

Ceria-based catalysts doped with manganese and copper were obtained via the hydrothermal synthesis. Four systems were synthesized: CeO (pure ceria), CeMn (Mn/Ce at. ratio = 1/19), CeCu (Cu/Ce at. ratio = 1/19) and CeMnCu (Mn/Cu/Ce at. ratio = 1/1/38). The catalytic activity of the prepared materials was tested for the CO and soot oxidations. Complementary techniques (XRD, N physisorption at − 196 °C, FESEM, XPS, Raman spectroscopy, CO-TPR and Soot-TPR) were performed to investigate their physico-chemical properties. The samples were characterized by nanocubes, in the case of CeO, and by nanopolyhedra for binary (CeMn and CeCu) and ternary oxides (CeMnCu). The CO-TPR analysis has confirmed that the reducibility follows the order: CeO < CeMn < CeMnCu < CeCu. A similar trend appears for the surface defective sites (Raman spectroscopy). These findings suggest the beneficial role of dopants in improving the structural defects and the surface reducibility of ceria. Both properties promote the CO oxidation activity. In fact, the CeCu was the most effective catalyst for the CO oxidation. The CeMn sample exhibited the best performance in soot oxidation. The following order was achieved: CeMnCu < CeCu < CeO ≈ CeMn, in agreement with the reduction profiles obtained by the Soot-TPR above 400 °C. Graphical Abstract: [ABSTRACT FROM AUTHOR]