Study of the impregnation sequence of active phase and effect of cobalt content over Co-CeO2/MgAl2O4 catalysts in ethanol steam reforming

Co-CeO2/MgAl2O4 catalysts were obtained by varying the impregnation order (sequential or co-impregnation) of active phase (Co) and Ce and were evaluated in the ethanol steam reforming (ESR) reaction. Results from TPR and XPS revealed that the impregnation order influenced the metal-metal and/or metal-support interactions and Co0/Con+, Ce3+/Ce4+ and the Co/Ce surface molar ratio, affecting the catalyst behavior in the ESR reaction. The solids prepared by sequential impregnation, Co/Ce/S and Ce/Co/S exhibited a greater de-gree of reduction than the solid obtained by co-impregnation (CoCe/S), though these systems displayed low dispersion of Co species and low content of surface Co & DEG;. The solid CoCe/S showed the highest dispersion (68.5%) and greater presence of Co0 on the surface. The effect of the cobalt content (4, 8 and 12 wt%) was also examined in catalysts prepared using the co-impregnation method. With the increase in cobalt content, a greater loss of stability and a greater amount of carbon deposits were observed. The highest H2 yield (5.3 mol H2/mol C2H5OH) and stability were achieved over the solid obtained by co -impregnation with 8 wt% Co, which was attributed to the high dispersion of the active phase and its high content of surface metallic cobalt. & COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.