Catalytic hydrodeoxygenation of phenol over graphene-supported Ru nanoparticles was investigated by means of periodic DFF calculations to propose a mechanism for the direct deoxygenation (DDO) pathway. The calculated interaction energies and activation barriers for the C-O scission on bare particle models of Ru/C catalysts are in good agreement with previous computational studies on the flat Ru(0001) surface and more realistic Ru surfaces with step edges and terraces. The results for graphene-supported Ru10Hx particles indicate that a model of the Ru/C catalyst with explicit hydrogens chemisorbed on the surface of metallic nanoparticle is essential for a complete understanding of the DDO process. (C) 2016 Elsevier By. All rights reserved.