Au25 clusters as precursors for the synthesis of AuPd bimetallic nanoparticles with isolated atomic Pd-surface sites

Abstract

This study documents the synthesis of Al2O3-supported AuPd bimetallic nanoparticles with isolated atomic Pd-surface sites using Au25(SC8H9)18 clusters as starting precursors. Here, previously synthesized thiolate protected AuPd bimetallic clusters were supported on Al2O3 and subjected to thermal and LiBH4 treatments. Extended X-ray absorption fine structure (EXAFS) analysis shows that thermal and LiBH4 treatments of Al2O3 supported AuPd bimetallic clusters result in the formation of AuPd/Al2O3 bimetallic nanoparticles with isolated atomic Pd-surface sites. EXAFS data also shows that Pd atoms present on the surface were still bonded with thiolate stabilizers. Finally, AuPd/Al2O3 catalysts were tested for the hydrogenation of allyl alcohol. Data show that while Au25/Al2O3 materials were inactive for the hydrogenation reaction, Al2O3 supported AuPd bimetallic clusters were catalytically active. The catalytic activity was further enhanced after thermal and LiBH4 treatment and this was attributed to the enhanced access of substrates to surface Pd sites.