Engineering intermetallic-metal oxide interface with low platinum loading for efficient methanol electrooxidation

Abstract

Constructing a distinctive electrochemical interface with low platinum content to boost the sluggish methanol electrooxidation kinetics is critical for commercializing the direct methanol fuel cells. Herein, we have synthesized highly active electrocatalysts with unique intermetallic-metal oxide interfaces through a facile pyrolysis method. Physical characterizations demonstrate that the obtained PtFe(1:2)@a-FeOx/NC-C catalyst with low platinum content of 7.2 wt% possesses an interfacial structure composed of face-centered tetragonal (L10) PtFe intermetallic nanoparticles accompanied with amorphous iron oxide. Electrochemical measurements show that the synthesized PtFe(1:2)@a-FeOx/NC-C catalyst not only exhibits excellent methanol electrooxidation activities with a mass activity of 1.48 A mg-1Pt and a specific activity of 2.34 mA cm-2Pt in acid medium, but also possesses better CO-tolerant performance and faster methanol oxidation kinetics compared with commercial Pt/C. The improved electrochemical performances may ascribe to the modified electronic structure by alloying platinum with iron and the special PtFe@a-FeOx interface, which render strong synergistic interactions between bimetallic PtFe nanoparticles and amorphous iron oxide. Consequently, the presented strategy offers new prospects into the construction of low-cost electrocatalysts with unique electrochemical interface for enhancing catalytic performances.