Ru-based nanoparticles were deposited on carbon nanotubes and graphene via an organometallic approach involving mixed-metal clusters modified with appropriate ligands. These ligands allowed either covalent or non-covalent pi-pi interactions with the carbonaceous surfaces. The immobilized clusters were then coalesced at different temperatures to give carbon-supported nanoparticles of different sizes. The obtained catalysts were tested in the selective hydrogenation of cinnamaldehyde. It was found that the nature of the metal(s), support nature, incorporation method and activation temperature all had a profound influence on activity and selectivity. Interestingly, the selectivity could be shifted from cinnamyl alcohol (COL) to hydrocinnamaldehyde (HCAL) by changing the reaction solvent. The best catalysts gave a very high selectivity in cinnamyl alcohol, which is not the more thermodynamically favored product, and could be reused several times without loss of activity or selectivity. (C) 2015 Elsevier Inc. All rights reserved.