Comparative investigation on the properties of carbon-supported cobalt-polypyrrole pyrolyzed at various conditions as electrocatalyst towards oxygen reduction reaction

• Pyrolyzed carbon-supported cobalt-polypyrrole as catalyst towards ORR.
• Effects of pyrolysis temperature and duration on the ORR performance.
• Transformation of cobalt acetate into CoO and then metallic cobalt.
• Quaterary-N plays important role on the ORR performance.
• Pyrolysis at 800 °C for 2 h is the optimal condition to prepare the best catalyst.

A series of non-precious metal catalysts named as Co-PPy-TsOH/C towards oxygen reduction reaction (ORR) were synthesized by pyrolyzing carbon supported cobalt-polypyrrole at various temperatures for diverse durations. The catalytic activity of these catalysts was evaluated with electrochemical techniques of cyclic voltammetry, rotating disk electrode and rotating ring-disk electrode. Physicochemical techniques, such as XRD, TEM and XPS, were employed to characterize the structure/morphology of the catalysts in order to understand the effects of pyrolysis conditions on the ORR activity. The results showed that both pyrolysis temperature and the duration have essential effects on the structure/morphology as well as ORR activity of the Co-PPy-TsOH/C catalysts, pyrolyzing the precursor at 800 °C for 2 h is the optimal condition to synthesize the catalyst with the best ORR performance.