Oxygen electroreduction on MN4-macrocycle modified graphene/multi-walled carbon nanotube composites

• rGO/CNT composite was modified with Fe and Co phthalocyanines followed by pyrolysis.
• rGO/CNT supported FePc and CoPc were used as catalysts for oxygen reduction reaction.
• Metal phthalocyanine/rGO/CNT showed a remarkable ORR activity in alkaline media.
• Metal phthalocyanine/rGO/CNT is an attractive catalyst for alkaline membrane fuel cells.

In this work the electrocatalysis of oxygen reduction on iron and cobalt phthalocyanine modified reduced graphene oxide/multi-walled carbon nanotube (rGO/MWCNT) composite catalyst has been investigated. Modification of the carbon support was achieved by pyrolysing the mixture of rGO/MWCNT in the presence of metallophthalocyanine compounds at 800 °C. The surface morphology, graphitisation and surface composition of the catalyst materials were characterised by transmission electron microscopy (TEM), scanning electron microscopy (SEM), micro-Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The oxygen reduction reaction (ORR) was studied in 0.1 M KOH and 0.5 M H2SO4 solutions on glassy carbon electrodes modified with MN4-macrocycle/rGO/MWCNT catalysts employing the rotating disk electrode (RDE) method. The RDE results show that both iron and cobalt phthalocyanine modified rGO/MWCNT electrocatalysts are highly active for ORR in alkaline solution while in acid media these materials exhibit only modest ORR activity.

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