Self-standing foam-like Pd-based alloys nanostructures for efficient electrocatalytic ethanol oxidation

In this work, self-standing binary porous PdM (M = Ni, Fe and Co) foam-like nanostructures are rationally designed by a rapid and one-step aqueous-solution method, including ice co-reduction of metal precursors using sodium borohydride. Amongst the tested PdM nanostructures, the PdNi nanostructures delivered a superior alkaline ethanol oxidation reaction (EOR) activity and stability than those of PdFe, PdCo, and commercial Pd/C catalysts. The EOR mass activity of PdNi (4.81 A/mgPd) was 1.32, 1.51, and 24.05-folds of PdFe (3.62 A/mgPd), PdCo (3.19 A/mgPd) and Pd/C (0.2 A/mgPd), respectively based on equal Pd mass loading. This was attributed to the lower synergetic effect of PdNi, which enhanced activation/dissociation of H2O to afford OH- species required for fast EOR kinetics; meanwhile, porous foam-like nanostructure improved electron mobility and increased accessible active sites. This study reveals that low synergism in porous PdM nanocrystals is beneficial for augmenting the EOR activity, which may allow the design of other binary Pd-based alloys for various electrocatalytic reactions.