Abstract
Nitrogen coordinated Fe single atoms (Fe-Nx SAs) anchored in carbon support is one of the most efficient electrocatalysts for oxygen reduction reaction (ORR). Engineering the microenvironment of Fe-Nx sites to achieve enhanced activity is still challenging. Herein, we theoretically demonstrate that nitrogen dopants in carbon skeletons can optimize the adsorption of ORR intermediates on Fe-N4 sites. Then, we introduce a rational strategy to anchor Fe-N4 sites in nitrogen-rich carbon support with abundant tubular channels (Fe-SAs@NCTCs). Fe-SAs@NCTCs exhibits encouraging ORR performance with a half-wave potential of 0.91 V in 0.1 M KOH and 0.80 V in 0.1 M HClO4. The assembled rechargeable Zn-air battery presents high power density and operates steadily with a narrow voltage gap of 0.76 V for 650 h. The results verify that the outstanding ORR activity can be attributed to the abundant nitrogen dopant, hierarchical porous structure, and abundant tubular channels.
NSTL