High stability of thiol-protected colloidal platinum nanoparticles with reduced ligand coverages in the hydrogenation of 3-hexyne

Abstract

The influence of different thiol ligands on the activity and particularly the stability of colloidal platinum nanoparticles is studied by using the catalytic semihydrogenation of 3-hexyne as model reaction. It is shown that a reduced ligand concentration during functionalization leads to an increase in the catalyst activity, while the stability of the particles as colloids in solution is surprisingly maintained, which also holds for the selectivity. Furthermore, it is demonstrated that the concept of reduced ligand coverages can also be applied to different thiol-based surfactants with varying steric demands. As shown for cyclohexanethiol-capped platinum nanoparticles, after eight recycling runs the particles maintain their activity and selectivity in all cycles. Electron microscopy further confirms that the particle size is preserved after the catalytic runs.