N-doped graphene analogue synthesized by pyrolysis of metal tetrapyridinoporphyrazine with high and stable catalytic activity for oxygen reduction

Abstract

We fabricated N-doped graphene analogue by pyrolysis of metal tetrapyridinoporphyrazine (MTAP), a kind of N rich metal phthalocyanine derivative with four pyridine substituents. The combination results of elemental analysis, X-ray photoelectron spectroscopy and electron-energy-loss spectrometry mapping show that the obtained N-doped graphene analogue is nitrogen-rich and has uniform distribution of C and N atoms. The atomic ratio of N/C in the obtained graphene is about 20.5%. The majority of N atoms are present in a pyridine type environment. Theoretical analysis based on DFT calculations has been performed for a deep understanding of the role of MTAP in the synthesis of the N-doped graphene analogue. Electrochemistry results show the N-doped graphene analogue exhibits a one-step, four-electron pathway for oxygen reduction reaction, and shows almost identical voltammetric responses before and after about 100 000 cycles, indicating that it has high and stable electrocatalytic activity for oxygen reduction.