Redox properties and VOC oxidation activity of Cu catalysts supported on Ce1−xSmxOδ mixed oxides

Highlights: • Complete elimination of ethyl acetate is achieved at 260 °C with Cu/CeO2 catalysts. • Samarium has a detrimental impact on VOC oxidation, proportional to its content. • Incorporation of Sm in ceria has a detrimental effect on textural characteristics and reducibility. • Increase of Sm/Ce ratio results in a more reduced Cu species, inactive for VOC oxidation. • A correlation between VOC activity and catalysts redox properties is established. -- Abstract: A series of Cu catalysts supported on Ce1−xSmxOδ mixed oxides with different molar contents (x = 0, 0.25, 0.5, 0.75 and 1), was prepared by wet impregnation and evaluated for volatile organic compounds (VOC) abatement, employing ethyl acetate as model molecule. An extensive characterization study was undertaken in order to correlate the morphological, structural and surface properties of catalysts with their oxidation activity. The optimum performance was obtained with Cu/CeO2 catalyst, which offers complete conversion of ethyl acetate into CO2 at temperatures as low as 260 °C. The catalytic performance of Cu/Ce1−xSmxOδ was interpreted on the basis of characterization studies, showing that incorporation of samarium in ceria has a detrimental effect on the textural characteristics and reducibility of catalysts. Moreover, high Sm/Ce atomic ratios (from 1 to 3) resulted in a more reduced copper species, compared to CeO2-rich supports, suggesting the inability of these species to take part in the redox mechanism of VOC abatement. Sm/Ce surface atomic ratios are always much higher than the nominal ratios indicating an impoverishment of catalyst surface in cerium oxide, which is detrimental for VOC activity