Engineering FeN4 active sites onto nitrogen-rich carbon with tubular channels for enhanced oxygen reduction reaction performance

Nitrogen coordinated Fe single atoms (Fe-N x SAs) anchored in carbon support is one of the most efficient electrocatalysts for oxygen reduction reaction (ORR). Engineering the microenvironment of Fe-N x 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-N 4 sites. Then, we introduce a rational strategy to anchor Fe-N 4 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 HClO 4 . 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. • DFT reveals that Fe-(N-C 2 ) 4 -2N achieves optimal adsorptions of ORR intermediates. • Fe-SAs@NCTCs possesses abundant Fe SAs in nitrogen-rich carbon support. • Hierarchical porous structure with tubular channels renders rapid mass transport. • Fe-SAs@NCTCs exhibits remarkable ORR performances in alkaline and acidic media. • Zn–air battery assembled using Fe-SAs@NCTCs shows excellent performance.