Boosting Electrocatalytic Activity of Single Atom Catalysts Supported on Nitrogen‐Doped Carbon through N Coordination Environment Engineering

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 18; no. 10; pp. e2105329 - n/a
• Main Authors: Zhang, Xiaoran, Xu, Xiaomin, Yao, Sixian, Hao, Chao, Pan, Can, Xiang, Xue, Tian, Zhi Qun, Shen, Pei Kang, Shao, Zongping, Jiang, San Ping
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.03.2022
• Subjects: Carbon; Catalytic activity; Chemical synthesis; Cobalt; Coordination; Density functional theory; Donors (electronic); Dopants; Electronic structure; Functionals; Mathematical analysis; Metal air batteries; N coordination environment engineering; Nanotechnology; Nitrogen; oxygen reduction reactions; polymer electrolyte membrane fuel cells; Proton exchange membrane fuel cells; Reaction kinetics; Single atom catalysts; Zinc-oxygen batteries; Zn–air batteries; N coordination environment engineering; polymer electrolyte membrane fuel cells; oxygen reduction reactions; Zn-air batteries; single atom catalysts
• DOI: 10.1002/smll.202105329
• ISSN: 1613-6810

Nonprecious group metal (NPGM)‐based single atom catalysts (SACs) hold a great potential in electrocatalysis and dopant engineering has been extensively exploited to boost their catalytic activity, while the coordination environment of dopant, which also significantly affects the electronic structure of SACs, and consequently their electrocatalytic performance, have been largely ignored. Here, by adopting a precursor modulation strategy, the authors successfully synthesize single cobalt atom catalysts embedded in nitrogen‐doped carbon, Co–N/C, with similar overall Co and N concentrations but different N types, that is, pyridinic N (NP), graphitic N (NG), and pyrrolic N (NPY). Co–N/C with the Co–N4 moieties coordinated with NG displays far superior activity for oxygen reduction (ORR) and evolution reactions, and superior activity and stability in both zinc–air batteries and proton exchange membrane fuel cells. Density functional theory calculation indicates that coordinated N species in particular NG functions as electron donors to the Co core of Co–N4 active sites, leading to the downshift of d‐band center of Co–N4 and weakening the binding energies of the intermediates on Co–N4 sites, thus, significantly promoting catalytic kinetics and thermodynamics for ORR in a full pH range condition. Cobalt single atom catalysts embedded in nitrogen‐doped carbon (Co–N/C) with the controlled N types, that is, pyridinic N (NP), graphitic N (NG), and pyrrolic N (NPY), are successfully synthesized via a precursor modulation strategy. Co–N/C with the Co–N4 moieties coordinated with NG displays superior activities for oxygen reduction and evolution reactions in wide pH ranges.