• Three Ag-CeO 2 /SiO 2 catalysts were prepared by different sequences of impregnation. • Red-ox reaction between Ce3+ surf and Ag+ aq provides strong Ag–CeO 2 interaction. • Ag–CeO 2 interaction enhanced oxidative dehydrogenation of ethanol to acetaldehyde. • Maximum of acetaldehyde yield ∼88% was achieved for Ag catalysts at 230–260 °C. • Control of interfacial interaction plays a key role for catalyst design. Three Ag-CeO 2 /SiO 2 catalysts were prepared by different methods, namely, sequential impregnation, co-impregnation and impregnation of pre-reduced CeO 2 /SiO 2 and are tested in the oxidative dehydrogenation of ethanol. The order of introduction of silver and ceria precursors is found to influence the catalytic activity that increases in the order of preparation method: sequential impregnation < co-impregnation < impregnation of pre-reduced CeO 2 /SiO 2. Results of TPR-H 2 , TEM HR, XPS and Raman characterizations show the best interfacial Ag–CeO 2 interaction and highest defectiveness of CeO 2 nanoparticles in the catalyst prepared by impregnation of pre-reduced CeO 2 /SiO 2. A correlation between Ag–CeO 2 interaction and catalytic activity is found in the series of Ag-CeO 2 /SiO 2 catalysts depending on the preparation method. Enhanced Ag–CeO 2 interfacial interaction leads to increased activity in oxidative dehydrogenation of ethanol. [ABSTRACT FROM AUTHOR]