The behavior of nanoparticles of copper and silver on an alumina support in the oxidation and dehydrogenation of ethanol is investigated. Pure alumina mainly acts as an acidic catalyst and produces diethyl ether and ethylene. Addition of copper and silver nanoparticles results in a direct conversion of ethanol into ethylene oxide. Addition of Li2O influences the selectivity by suppressing the formation of diethyl ether and ethylene. Using Ag/Li2O/Al2O3 and Cu/Li2O/Al2O3 catalysts it is possible to obtain high selectivity towards ethylene oxide at a temperature of 200 degrees C. It is suggested that at low concentrations the main role of oxygen is to prevent coke formation on the catalytic surface. Addition of CeOx results in higher selectivities towards CO. (C) 2010 Elsevier B.V. All rights reserved.