Metallomacrocyclic-carbon complex: A study of bifunctional electrocatalytic activity for oxygen reduction and oxygen evolution reactions and their lithium-oxygen battery applications

•A superior bifunctional FePc-carbon electrocatalyst is proposed for Li-O2 battery.•Proposed composites exhibit better catalytic activity in both ORR and OER than Pt/C.•RGO_BM FePc exhibits the highest activity with good reversibility and overpotential.•Ball-milling effect and role of carbon in improving catalytic activity are detailed.

A metallophthalocyanine - carbon complex is designed by a simple approach to achieve superior, bifunctional catalytic activity. A simple and cost-effective technique is utilized to prepare carbon_iron phthalocyanine composites. Furthermore, to investigate ball milling effects, iron phthalocyanine is ball milled, which is used to prepare the carbon_ball-milled iron phthalocyanine composites. All the prepared composites exhibit better catalytic activity in both oxygen reduction and oxygen evolution reactions than Pt/C, indicating carbon support significantly improves the stability, conductivity, and surface properties of iron phthalocyanine. The ball-milling improves specific surface area, which in turn enhances the oxygen evolution reaction activity of the composites. When the carbon-iron phthalocyanine composites were applied to an air-cathode catalyst in a lithium-oxygen battery, high reversibility and low over-potential were attained. Among all the synthesized catalysts, the reduced graphene oxide_ball-milled iron phthalocyanine composite exhibits superior bifunctional electrocatalytic activity with high reversibility (92%) and low over-potential (0.7 V) due to enhanced surface properties.

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