TY - JOUR
T1 - Solvent-mediated oxidative polymerization to atomically dispersed iron sites for oxygen reduction
AU - Yao, Xiuyun
AU - Zhu, Youqi
AU - Han, Zhanli
AU - Yang, Lifen
AU - Tian, Jiachen
AU - Xia, Tianyu
AU - Peng, Hui
AU - Cao, Chuanbao
N1 - Publisher Copyright:
© 2023 Elsevier B.V.
PY - 2023/8/15
Y1 - 2023/8/15
N2 - Fe single-atom catalysts open up broad prospects for oxygen reduction reaction (ORR), but the chemical state evolution of Fe species before forming isolated sites is rarely understood. Herein, mechanistic investigation on the formation of isolated Fe sites is presented through solvent-mediated oxidative pyrrole polymerization strategy. The slow reaction kinetics of oxidative Fe3+ ions with the predesigned methanol solvent molecules can endow highly dispersed Fe sites in polypyrrole and thus Fe single-atom catalysts after pyrolysis. The Fe single-atom catalyst (Fe-SA/PNC) performs superior ORR activity with a half-wave potential of 0.90 V versus RHE and 12.8 times higher turnover frequency than that of commercial Pt/C. When assembled into Zn-air batteries, the Fe-SA/PNC cathode delivers a 1.68 V open circuit potential and ultra-long cycling stability over 9000 cycles, superior to the most reported catalysts so far. Experimental and theoretical results reveal that the rich adjacent non-coordinated graphitic nitrogen atoms can enhance electronic conductivity and promote O2 adsorption and OH- desorption, thus enabling high oxygen reduction and battery performances.
AB - Fe single-atom catalysts open up broad prospects for oxygen reduction reaction (ORR), but the chemical state evolution of Fe species before forming isolated sites is rarely understood. Herein, mechanistic investigation on the formation of isolated Fe sites is presented through solvent-mediated oxidative pyrrole polymerization strategy. The slow reaction kinetics of oxidative Fe3+ ions with the predesigned methanol solvent molecules can endow highly dispersed Fe sites in polypyrrole and thus Fe single-atom catalysts after pyrolysis. The Fe single-atom catalyst (Fe-SA/PNC) performs superior ORR activity with a half-wave potential of 0.90 V versus RHE and 12.8 times higher turnover frequency than that of commercial Pt/C. When assembled into Zn-air batteries, the Fe-SA/PNC cathode delivers a 1.68 V open circuit potential and ultra-long cycling stability over 9000 cycles, superior to the most reported catalysts so far. Experimental and theoretical results reveal that the rich adjacent non-coordinated graphitic nitrogen atoms can enhance electronic conductivity and promote O2 adsorption and OH- desorption, thus enabling high oxygen reduction and battery performances.
KW - Alkaline reversible Zn-air batteries
KW - Chemical state evolution
KW - Fe single-atom catalyst
KW - High open circuit potential
KW - Ultra-long cycling stability
UR - http://www.scopus.com/inward/record.url?scp=85151014899&partnerID=8YFLogxK
U2 - 10.1016/j.apcatb.2023.122675
DO - 10.1016/j.apcatb.2023.122675
M3 - Article
AN - SCOPUS:85151014899
SN - 0926-3373
VL - 331
JO - Applied Catalysis B: Environmental
JF - Applied Catalysis B: Environmental
M1 - 122675
ER -