Composition-tunable PtCu alloy nanowires and electrocatalytic synergy for methanol oxidation reaction

The ability to impart Pt-based catalysts with high catalytic activity and low cost is essential for advancing fuel cell technologies. This report describes the synthesis of composition-tunable PtCu alloy nanowires (NWs) of ultrathin diameters (ca. 1 nm) to create synergistic catalytic sites along the nanowire surfaces. The bimetallic NWs exhibit composition-tunable fcc-type alloy phase. The electrocatalytic properties of the PtCu alloy NWs for methanol oxidation reaction were shown to display an intriguing composition-dependent catalytic synergy. The maximum mass activity for Pt₃₂Cu₆₈ NWs was about 2 times higher than that of Pt NWs. It also exhibited the highest stability and tolerance to CO poisoning. The enhanced activity and stability were attributed to a bifunctional synergy whereby the alloyed Cu atoms in the Pt lattice provides COmaneuvering sites for reducing the poisoning effect of CO intermediate species on the active surface sites of the NWs.