A solvothermal synthesis of phosphorus doped carbon nanotube as a bi-functional electrocatalyst for oxygen reduction and oxygen evolution reaction

Abstract

Electrocatalysts for the oxygen reduction and oxygen evolution reactions play a critical role in the performance of metal-air batteries. In this study, a phosphorus doped carbon nanotube (P-CNT) is facilely synthesized via a one-step process and in-situ solvothermal method. The electrocatalytic activity for the oxygen reduction reaction (ORR) and oxygen evolution reaction(OER) of the catalyst was studied with the rotating ring-disk electrode (RRDE) technique. The doping of phosphorus can obviously improve the electrocatalytic activity of CNT towards both the ORR and OER. Four electron reduction pathway is dominant on P-CNT during the ORR process, which is comparable to the commercial Pt/C (20 wt%). The electrocatalytic activity of P-CNT towards the OER is superior to that of Pt/C (20 wt%). Moreover, the long-term stability of P-CNT outperforms that of Pt/C (20 wt%). The high electrocatalytic activity and long-term stability of P-CNT are attributed to P-doping in CNT and the strong coupling between phosphorus and carbon.