Quatermetallic Pt-based ultrathin nanowires intensified by Rh enable highly active and robust electrocatalysts for methanol oxidation

Abstract

Inferior stability and anti-poisoning capacity of Pt-based ultrathin nanowires (NWs) are critical weaknesses under detrimental acidic running conditions for proton-exchange membrane fuel cell applications due to their energetic surface. Here 1.5-nm-thin quatermetallic PtCoNiRh NWs with high atomic-exposure are fabricated to serve as robust electrocatalysts for acidic methanol oxidation reaction (MOR). Surpassing Rh-free PtCoNi NWs and most of state-of-the-art catalysts, the PtCoNiRh NWs achieve extremely high MOR activity (1.36 A·mg−1Pt and 2.08 mA cm−2) with substantially lowered onset-potential and improved CO-tolerance. The anticorrosion effect of incorporated-Rh can effectively stabilize the PtCoNiRh NWs in the corrosive MOR. Electrochemical in situ Fourier transform infrared spectroscopy and density functional theory simulation cooperatively reveal that the methanol dehydrogenation is inclined to occur at the interatomic Pt–Rh sites, where the intermediate COads prefers bridge binding mode rather than linear mode with facilitated removal. Integratedly, the complete 6e−-transferred MOR process is reliably accelerated and stays efficient on the quaternary PtCoNiRh NWs.