Platinum-Ruthenium Nanoparticles: Active and Selective Catalysts for Hydrogenation of Phenylacetylene

Bimetallic metal nanoparticles are often more catalytically active than their monometallic counterparts, due to a so-called 'synergistic effect'. Atomically precise ruthenium-platinum clusters have been shown to be active in the hydrogenation of phenylacetylene to styrene (a reaction of importance to the polymer industry). However, the synthesis of these clusters is generally complex, and cannot be modified to produce clusters with differing metal compositions or ratios. Hence, any truly systematic study of compositional effects using such clusters is hindered by the inaccessibility of certain metal ratios. In this study, a series of larger bimetallic ruthenium-platinum colloids of varying metal ratios was synthesised in solution and immobilised on silica. Catalytic activity was evaluated by hydrogenation of phenylacetylene to styrene. Both bimetallic and monometallic colloids were active catalysts for the hydrogenation of phenylacetylene to styrene and further to ethylbenzene. Of those studied, a catalyst composed of 73% platinum-27% ruthenium (by moles) showed the highest activity. This suggests that synergistic effects play an important role in the catalysis of this reaction. To our knowledge this is the first systematic study of ruthenium-platinum nanoparticle catalytic activity on this reaction.