Tunable active-sites of Co- nanoparticles encapsulated in carbon nanofiber as high performance bifunctional OER/ORR electrocatalyst

The development of low-cost electrocatalysts with high oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) performance is crucial for devices used to convert and store hydrogen energy. Research on OER and ORR catalysts has attracted a lot of attention. The limited single-functional catalysts can be expanded as bi-functional catalysts to meet the extra requirement of preparing high-performance catalysts. In this study, we prepared Co-ZIF/CNF in which carbon nanofibers uniformly encapsulated Conanoparticles by electrospinning and simple pyrolysis. Co-ZIF/CNF contains both CoOx and Co-N-y active sites, showing bifunctional activity for OER and ORR. The optimized catalyst Co-ZIF(1.5)/10CNF(2) has a low OER overpotential of 390 mV, an onset potential of 0.93 V and a half-wave potential of 0.85 V of ORR, exhibiting an outstanding OER and ORR catalytic performance. The catalyst retained 87.53 % of its current after 12 h, showing great stability. This paper provides a new strategy for designing and preparing OER and ORR bifunctional catalysts. (c) 2022 Published by Elsevier Inc.

Automated summary

In this study, low-cost Co-ZIF/CNF electrocatalysts with high OER and ORR performance were prepared using electrospinning and simple pyrolysis. The Co-ZIF/CNF catalysts contain both CoOx and Co-N-y active sites, exhibiting bifunctional activity for OER and ORR. The optimized catalyst Co-ZIF(1.5)/10CNF(2) shows outstanding OER and ORR catalytic performance with a low OER overpotential of 390 mV, an onset potential of 0.93 V, and a half-wave potential of 0.85 V for ORR. The catalyst also demonstrates great stability with 87.53% current retention after 12 hours. This study provides a new strategy for designing and preparing bifunctional catalysts for OER and ORR.