On the role of bismuth as modifier in AuPdBi catalysts: Effects on liquid-phase oxidation and hydrogenation reactions

There is much about the action of bismuth within heterogeneous catalysis that still require a deeper understanding. We observed that, when Bi was added to AuPd bimetallic nanoparticles (NPs) supported on activated carbon, Bi affected the activity and significantly alters the selectivity in two model liquid phase reactions, namely the oxidation of cinnamyl alcohol and the hydrogenation of cinnamaldehyde. A combination of transmission electron microscopy and X-ray absorption spectroscopy provided a detailed characterization of trimetallic AuPdBi systems. We propose that the introduction of bismuth on AuPd NPs results in a partial blockage of most active sites, limiting the occurrence of consecutive reactions.