Sulfur‐Tuned Main‐Group Sb−N−C Catalysts for Selective 2‐Electron and 4‐Electron Oxygen Reduction

• Published in: Advanced materials (Weinheim) Vol. 36; no. 27; pp. e2402963 - n/a
• Main Authors: Yan, Minmin, Yang, Hao, Gong, Zhichao, Zhu, Jiarui, Allen, Christopher, Cheng, Tao, Fei, Huilong
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.07.2024
• Subjects: Catalysts; catalytic selectivity; Chemical reduction; Controllability; Dopants; Electronic structure; Energy conversion; Fuel cells; Hydrogen peroxide; main‐group metals; Metal air batteries; oxygen reduction reaction; Oxygen reduction reactions; Selectivity; single atom catalysts; Sulfur; Sulfur content; sulfur doping; Zinc-oxygen batteries; sulfur doping; main‐group metals; catalytic selectivity; oxygen reduction reaction; single atom catalysts
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202402963

The selective oxygen reduction reaction (ORR) is important for various energy conversion processes such as the fuel cells and metal‐air batteries for the 4e− pathway and hydrogen peroxide (H2O2) electrosynthesis for the 2e− pathway. However, it remains a challenge to tune the ORR selectivity of a catalyst in a controllable manner. Herein, an efficient strategy for introducing sulfur dopants to regulate the ORR selectivity of main‐group Sb−N−C single‐atom catalysts  is reported. Significantly, Sb−N−C with the highest sulfur content follows a 2e− pathway with high H2O2 selectivity (96.8%) and remarkable mass activity (96.1 A g−1 at 0.65 V), while the sister catalyst with the lowest sulfur content directs a 4e− pathway with a half‐wave potential (E1/2 = 0.89 V) that is more positive than commercial Pt/C. In addition, practical applications for these two 2e−/4e− ORR catalysts are demonstrated by bulk H2O2 electrosynthesis for the degradation of organic pollutants and a high‐power zinc‐air battery, respectively. Combined experimental and theoretical studies reveal that the excellent selectivity for the sulfurized Sb−N−Cs is attributed to the optimal adsorption‐desorption of the ORR intermediates realized through the electronic structure modulation by the sulfur dopants. A series of main‐group Sb−N−C single‐atom catalysts are developed with varied oxidation states of the Sb sites via changing the contents of sulfur dopants, resulting in tunable ORR selectivity toward either the 4‐electron or 2‐electron pathway.