Deciphering the Role of Native Defects in Dopant-Mediated Defect Engineering of Carbon Electrocatalysts
Ning Li, Mengyang Li, Kun Guo*, Ziqian Guo, Ruijie Wang, Lipiao Bao, Gao-Lei Hou*, Xing Lu*
Adv. Energy Mater. 2024, 2401008
https://doi.org/10.1002/aenm.202401008
Abstract
Doping–dedoping chemistry lays the cornerstone for converting heteroatom dopants into intrinsic defects as the emerging active sites of carbon catalysts, but the defect content is yet hindered by inadequate doping efficiencies. Comprehending crucial factors behind the doping of pristine carbon and their correlation to the catalytic properties of dedoped carbon is thus of high significance. Here, the overlooked impact of native defects in pristine carbon on dopant-mediated defect engineering of carbon catalysts is explicitly unveiled. Intact fullerene (C60), C60-derived carbon, and carbon black in distinct pentagon/edge defect states are employed as respective precursors to undergo a nitrogen doping–dedoping treatment. Theoretical and experimental evidence consistently indicates that native pentagons change the preferred N doping site from the edge to the basal plane, leading to a substantially higher doping level. Importantly, in addition to pentagons from the removal of zigzag-edged pyridinic N, N dopants in in-plane pentagons are more easily dedoped than those in hexagons, generating even more pentagons in a new pentagon–heptagon–pentagon structure as oxygen reduction active sites. The optimized defect-rich carbon gives an outstanding half-wave potential of 0.834 V (0.846 V for Pt/C) via the four-electron pathway, excellent long-term durability, and prospective applicability in zinc–air batteries.
