The enhanced electrocatalytic activity and stability of supported Pt nanopartciles for methanol electro-oxidation through the optimized oxidation degree of carbon nanotubes

• The oxidized states of CNTs were controlled by varied amounts of KMnO4 with a Hummer's method.
• Pt/MO-CNTs showed the best performance towards MOR.
• The Pt/MO-CNTs catalyst exhibited good activity and stability in single cell test.
• The enhancement was due to the small metal size and the modified electron structure.

Carbon nanotubes (CNTs) with different oxidation degrees are synthesized by the modified Hummer's method and used as the support materials for platinum (Pt) catalysts. The effect of their oxidation degree on the catalytic activity and stability of the supported Pt catalysts for methanol electrooxidation is investigated for the first time. The electrocatalytic activity for methanol oxidation reaction increases with increasing the oxidation degree due to more oxygen-containing species introduced to CNTs, which improves the dispersion of Pt nanoparticles and also modifies the electronic structure of Pt catalysts. However, under more severe oxidation condition, the stability of Pt catalysts decreases due to the destruction of graphitic structure of CNTs. Therefore, the optimized treatment condition for the CNTs is mild oxidation, which provides the supported Pt catalysts with both excellent catalytic activity and stability.

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