Carbon supported Au–Pd core–shell nanoparticles for hydrogen production by alcohol electroreforming

Abstract

Bimetallic nanoparticle catalysts generally exhibit enhanced activity and selectivity in electrocatalytic reactions as combining metals allows tuning of the electronic and surface structures. In this article, monodisperse faceted icosahedral Au–Pd core–shell nanocrystals of small size (<12 nm) supported on Vulcan XC-72 (Au–Pd/C) are investigated for hydrogen production by alcohol electroreforming. We investigate a range of renewable alcohols including diols, such as ethylene glycol, glycerol, 1,2-propanediol, 1,3-propanediol, and 1,4-butanediol. Au–Pd/C shows selectivity for the partial oxidation of the diols to the corresponding mono-carboxylates. These include chemicals like lactate and glycolate that are important industrial intermediates. We have also investigated changes to the catalyst nanostructure under electrocatalytic conditions. Significantly, clustering of the NPs on the carbon support occurs without a negative effect on the activity. The palladium shell becomes elongated suggesting some migration of Pd from the shell occurring through alloy formation at the gold–palladium interface.