Ultrathin Pt3Pb nanowires prepared in the aqueous phase for enhanced methanol electrooxidation

Abstract

Pt-based alloy nanowires have become an ideal platform for commercial application in direct methanol fuel cells (DMFCs). Regrettably, most of the nanowires are prepared in an oil phase system. The plentiful hydrophobic molecules are adsorbed on the surface of the nanowires and build a barrier that prevents mass transfer of the substrate molecules, resulting in the decrease of the catalytic efficiency. Therefore, it is very urgent to prepare Pt-based nanowires in an aqueous system to improve the performance of electrocatalysts. Herein, we use a H₂-assisted strategy to prepare 3.5 nm-thin Pt₃Pb nanowires in aqueous solution. Taking the methanol oxidation reaction as the catalytic model, the Pt₃Pb nanowires show mass activity of 3.56 A mg⁻¹ and specific activity of 7.46 mA cm⁻² for the MOR, which are 4.88 and 4.60 times higher than those of Pt/C. The improved performance of the Pt₃Pb nanowires is attributed to the ultrathin structure, synergistic effect of the alloy and abundant accessible defects.