Synthesis and characterization of Pt3Co bimetallic nanoparticles supported on MWCNT as an electrocatalyst for methanol oxidation

Abstract

The impregnation method was used to synthesize Pt and Pt₃Co supported on MWCNTs applying NaBH₄ as the reducing agent. The structure, morphology, and chemical composition of the electrocatalysts were characterized through SEM, XRD, and EDX. X-ray diffraction showed a good crystallinity of the supported Pt nanoparticles on the composites and showed the formation of Pt₃Co alloy. The SEM images revealed that the particles of Pt₃Co were deposited uniformly on the surface of MWCNT with a diameter of 10 nm. EDX analysis confirmed the surface segregation of Co and Pt occurred (1:3 surface atomic ratio Pt-Co) for the Pt₃Co/MWCNT nanocomposite. The Pt₃Co/MWCNTs and Pt/MWCNTs electrocatalysts' electrochemical performance was assessed against the methanol oxidation reaction (MOR) in 0.5 M H₂SO₄ solution using the chronoamperometry (CA) and the cyclic voltammetry (CV) methods. The minimum onset potential and the largest oxidation current density were obtained at Pt₃Co/MWCNTs electrocatalyst. The Pt₃Co/MWCNT catalyst with a good alloying degree has been shown to have better anti-poisoning ability, electrochemical activity, and long-term durability than Pt/MWCNT catalysts, approved by the bimetallic catalysts' bi-functional mechanism.