Ethanol and ethanol dimer dehydrogenation to ethoxy on Cu surfaces were studied using DFT calculations with the PBE/DNP method. The dehydrogenation barrier decreases from 1.15 eV on Cu(111) to 0.72 eV on Cu(110) and further to 0.67 eV on Cu(100). The presence of hydrogen bond decreases the barrier to 1.02 eV on Cu(111) and 0.67 eV on Cu(110), but increases the barrier to 0.75 eV on Cu(100). Thus, the most effective catalyst surface is the clean Cu(100) and the ethanol adsorbed Cu(110). These results were analyzed based on the d-band center theory and the structural information of the adsorbed molecules. (C) 2013 Elsevier B.V. All rights reserved.