Electrospun cobalt nanoparticles embedded in pyrrole doped hollow mesoporous carbon nanofibers as efficient and durable oxygen electrocatalysts for rechargeable zinc-air battery

Abstract

The development of a bifunctional electrocatalyst with high durable activity and cost-effectiveness is the bottleneck of rechargeable Zinc-air batteries (RZABs) technology. Herein, by using the synergistic effect of pyrrole and cobalt, we synthesized a catalyst-cobalt nanoparticle-embedded pyrrole-doped hollow porous carbon nanofiber (Co-Py/HMPCNF) by a convenient electrospinning and high-temperature calcination route. We found that the addition of pyrrole significantly improved the ORR (oxygen reduction reaction) and OER (oxygen evolution reaction) activities of the catalyst, and the optimized Co-Py(1.5mL)/HMPCNF-900 (with a pyrrole content of 1.5 mL and a carbonization temperature of 900 °C) exhibited a positive onset potential (1.055 V) for ORR and OER showed excellent oxygen electrocatalytic activity and stability in terms of low overpotential (0.36 V at 10 mA cm−2), the RZABs constructed using Co-Py(1.5mL)/HMPCNF-900 exhibited an open-circuit voltage of 1.42 V, which is comparable to the Pt/C system, and its stability still does not fail after 278 h, which is better than that of the Pt/C catalyst. A detailed comparison of Co-Py(1.5mL)/HMPCNF-900 with other similar catalyst studies (Table S2) shows that Co-Py(1.5mL)/HMPCNF-900-based catalyst has great potential for practical application of RZABs and it is worth mentioning that the preparation process of this catalyst is simple and inexpensive.