▎ 摘　　要

Tuning active configurations of different nitrogen (N) species and elucidating their influence on the catalytic activity for oxygen reduction reaction (ORR) is important to develop N-doped carbon (N/C) as efficient metal-free catalysts. The challenge is to selectively control the active N sites of N/C. Herein, we approach this challenge by modulating N active species in graphene structured N/C with specific precursors via a one-step pyrolysis process. In this method, 5-aminouracil is selected as the N-containing precursor platform to modulate the pyridinic N (NP), while 2,6-diaminopyridine and 1,3-diaminobenzene are used to modulate graphitic N (NG) and pyrrolic N (NPY), respectively. N/C materials with specific different N configurations such as N/C -NP + NG, N/C -NP + NP and N/C -NP + NPY are successfully synthesized and identified by microstructure and phase characterization. Electrochemical results demonstrate that N/C -NP + NG exhibits the best ORR performance, achieving an onset potential (E-onset) of 0.98 V and half-wave potential (E-1/2) of 0.86 V vs. RHE, respectively, which is comparable to that obtained on conventional Pt/C. By contrast, N/C -NP + NPY exhibits the lowest activity for ORR. Density functional theory (DFT) simulation further validates that the NP + NG configuration produces strong electronic distribution on carbon matrix that leads to high charge and high spin density on surrounding carbon atoms. This work provides a facile approach to design N doped graphene structured carbon materials with active N configurations for ORR. (C) 2021 Elsevier Ltd. All rights reserved.