Synthesis of Pt–Co nanoparticles on multi-walled carbon nanotubes for methanol oxidation in H2SO4 solution

Pt and Pt–Co supported on MWCNTs were synthesized by the impregnation method using NaBH4 as the reducing agent. The effect of varying NaBH4 concentration on particle size, morphology and chemical composition of Pt–Co/MWCNTs was studied. A homogeneous distribution of Pt–Co nanodeposits with particle size of 2–5 nm was attained in TEM images at Pt–Co/MWCNTs “×70” powder. EDX analysis confirmed the reduction of higher amount of Co in Pt–Co/MWCNTs “×40” electrocatalyst. The electrochemical activity of Pt/MWCNTs and Pt–Co/MWCNTs electrocatalysts was examined towards methanol oxidation reaction in 0.5 M H2SO4 solution by employing the cyclic voltammetry and the chronoamperometry techniques. The lowest onset potential and the highest oxidation current density were gained at Pt–Co/MWCNTs “×70” electrocatalyst. Its good stability over the long-term performance study elects it as a promising candidate for the DMFCs applications.

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► Pt Co nanodeposits with particle size of 2–5 nm are formed.
► Higher amount of Co in Pt–Co/CNTs “×40” is reduced.
► Pt–Co/CNTs “×70” electrode records the lowest potential of methanol oxidation.
► Pt–Co/CNTs “×70” electrode showed long-term cycleability and CO tolerance.