Effects of composition on electrochemical properties of a non-precious metal catalyst towards oxygen reduction reaction

• Co-PPy-TsOH/C as catalysts towards oxygen reduction reaction (ORR).
• Co-PPy-TsOH/C prepared with various amount of pyrrole and TsOH.
• Elemental contents of Co, N, C, S, H and O in Co-PPy-TsOH/C catalysts.
• Electrochemical properties of ORR peak potential and electron-transfer number.
• Correlation between pyrrole/TsOH amount, elemental contents and properties.

A family of non-precious metal catalysts, Co-PPy-TsOH/C, has been synthesized with different amount of pyrrole and p-toluenesulfonic acid (TsOH). Elemental contents of Co, N, C, S, H and O in the obtained catalysts have been measured with physicochemical techniques and the performance of these catalysts towards oxygen reduction reaction (ORR) have been evaluated with electrochemical techniques. Then, the results obtained have been discussed with principal component analysis and linear correlation analysis to find the correlation/anticorrelation between the composition and electrochemical properties. It is revealed that the used amount of pyrrole has much more apparent effect than TsOH on elemental contents in the Co-PPy-TsOH/C catalysts, while both of them influence the ORR activity and mechanism of the catalysts. Besides, the effects of the contents of each element on the electrochemical performance have also been analyzed to guide the future development of similar catalysts.