Abstract
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•Facile synthesis of iron phthalocyanine nanoparticles and their composite.•Synergist distal effect on nanosized FePc via O-atom on CNTs surface.•An inclusive relationship between Fe3+/2+ redox and ORR potentials.•Superior ORR performance of iron phthalocyanine nanoparticles.
The lethargic kinetics of oxygen reduction reaction (ORR) at cathode typically desires to be catalyzed by highly competent catalysts to get better performance of fuel cell devices for efficient energy conversion. Herein, we fabricated a nanocomposite of multiwall carbon nanotubes decorated with iron phthalocyanine nanoparticles (FePcNPs@CNTs) using a single-step facile microwave strategy. The morphologies and composition of the FePcNPs and FePcNPs@CNTs were confirmed by using multiple analytical techniques. Further, these materials were taken under the ORR electrocatalytic investigations in O2-saturated 0.1 M KOH. The results demonstrated the composite FePcNPs@CNTs to have superior ORR activity as evidenced by the significant reduction in over-potential (onset potential, +1.03 V and half-wave potential, +0.97 V) in comparison to commercial FePc and 20% Pt/C. In addition, the electrochemistry of FePcNPs, FePcNPs@CNTs in N2-saturated 0.1 M KOH indicated that more positive formal potential of Fe2+/Fe3+ redox couple facilitated the strong interaction between Fe2+ and O2; weaken the OO bond followed by 4e− ORR. This work confirms that bio-inspired molecules at the nanoscale can be applied to achieve 4e− ORR.