Cobalt tetramethoxyphenylporphyrin functionalized graphene for oxygen reduction reaction in neutral media

• CoTPP modified graphene (CoTPP–graphene) is successfully synthesized.
• The method used here can prevent the aggregation of graphene.
• CoTPP–graphene can be a good alternative to Pt for oxygen reduction reaction in neutral media.

Graphene was modified with cobalt tetramethoxyphenylporphyrin (CoTPP) by an ultrasonic treatment and was used as a non-noble catalyst for oxygen reduction reaction (ORR) in neutral media. The resulting CoTPP–graphene was characterized by scanning electron microscopy (SEM), UV–vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy, which confirmed that CoTPP could be strongly supported onto graphene through π–π interaction. The electrochemical activity of CoTPP–graphene towards ORR was evaluated by cyclic voltammogram (CV). The CV results suggested the excellent catalytic activity of CoTPP–graphene in neutral electrolytes. Compared to electrodes modified with the mechanical mixture of graphene and CoTPP (N-CoTPP–graphene), the peak potential of ORR detected at the CoTPP–graphene electrode was more positive and the peak current was much higher, implying the necessary of ultrasonic and the enhanced activity of CoTPP after adsorbing on graphene surface. Thus, the CoTPP–graphene can be used as a good catalyst for ORR.