Pt-based bimetallic nanoparticles supported on reduced graphene oxide were prepared by a facile NaBH4 reduction and chemically probed in the selective hydrogenation of cinnamaldehyde to cinnamyl alcohol (CAO). Compared with other metals (Fe, Ni, Cu, Zn), Co effectively promoted the catalytic performance. When the mass ratio of Pt:Co was 5:1, the selectivity to CAO was 89.5 % with 94.6 % conversion, which were higher than exclusively using Pt catalyst. The enhanced selectivity and activity might be attributed to the change of the electronic environment on Pt metal surface through metal-metal interaction.