Powder and structured catalysts based on CuO-CeO2 nanoparticles dispersed on different silica are studied in CO preferential oxidation. Silica of natural origin (Celite) and fumed silica (aerosil), both commercial materials, and synthesized mesoporous SBA-15 with 20, 200 and 650 m(2)g(-1) respectively, are selected as supports. CuCe/Celite coated on cordierite monolith displays the highest activity, reaching CO conversion above 90% between 140 and 210 degrees C and more than 99% around 160 degrees C. The addition of 10% CO2 and 10% H2O partially deactivates the monolithic catalyst. The lower surface area of CuCe/Celite favors the contact between CuO and CeO2 nanoparticles promoting a better interaction of Cu+2/Cu+ and Ce+3/Ce+4 redox couples. Raman spectroscopy reveals oxygen vacancies and XPS results show high metal lattice surface oxygen concentration and surface enrichment of Cu and Ce which promote the catalytic activity. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.