Enhancement of electrocatalytic properties of carbonized polyaniline nanoparticles upon a hydrothermal treatment in alkaline medium

The electrocatalytic activity of carbonized polyaniline nanostructures (Carb-nanoPANI) towards oxygen reduction reaction (ORR), estimated in 0.1 mol dm−3 KOH solution, was significantly improved upon a hydrothermal treatment in 1 mol dm−3 KOH solution. Namely, the onset of ORR was shifted by ∼70 mV to more positive potentials, and the number of electrons consumed per O2 molecule was enhanced in comparison to the original material. The number of electrons involved in ORR depended on loading, and with a loading of 0.5 mg cm−2, for the potentials lower than −0.5 V vs SCE, the number of electrons approached 4. For this material, high stability of electrochemical behavior and resistance to the poisoning by ethanol was evidenced by potentiodynamic cycling.

► Carbonized polyaniline nanoparticles were treated hydrothermally in 1 M KOH.
► Hydrothermal treatment improved the electrocatalytic activity towards ORR.
► Significant effect of catalyst loading was evidenced too.
► At the loading 0.5 mg cm−2 the 4e− reaction path was achieved.