Unraveling the High-Activity Origin of Single-Atom Iron Catalysts for Organic Pollutant Oxidation via Peroxymonosulfate Activation

• Published in: Environmental science & technology Vol. 55; no. 12; pp. 8318 - 8328
• Main Authors: Gao, Yaowen, Zhu, Yue, Li, Tong, Chen, Zhenhuan, Jiang, Qike, Zhao, Zhiyu, Liang, Xiaoying, Hu, Chun
• Format: Journal Article
• Language: English
• Published: Easton American Chemical Society 15.06.2021
• Subjects: Binding sites; Catalysts; Catalytic oxidation; Contaminants; Dissolved oxygen; Dosage; Environmental cleanup; Industrial wastes; Industrial wastewater; Iron; Nanoparticles; Organic contaminants; Oxidation; Pollutants; Reduction; Single atom catalysts; Treatment and Resource Recovery; Wastewater; Wastewater treatment; single-atom catalysts; electronic polarization; organic pollutant oxidation; electron migration; PMS reduction and oxidation
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/acs.est.1c01131

Single-atom catalysts (SACs) have emerged as efficient materials in the elimination of aqueous organic contaminants; however, the origin of high activity of SACs still remains elusive. Herein, we identify an 8.1-fold catalytic specific activity (reaction rate constant normalized to catalyst’s specific surface area and dosage) enhancement that can be fulfilled with a single-atom iron catalyst (SA-Fe-NC) prepared via a cascade anchoring method compared to the iron nanoparticle-loaded catalyst, resulting in one of the most active currently known catalysts in peroxymonosulfate (PMS) conversion for organic pollutant oxidation. Experimental data and theoretical results unraveled that the high-activity origin of the SA-Fe-NC stems from the Fe–pyridinic N4 moiety, which dramatically increases active sites by not only creating the electron-rich Fe single atom as the catalytic site but also producing electron-poor carbon atoms neighboring pyridinic N as binding sites for PMS activation including synchronous PMS reduction and oxidation together with dissolved oxygen reduction. Moreover, the SA-Fe-NC exhibits excellent stability and applicability to realistic industrial wastewater remediation. This work offers a novel yet reasonable interpretation for why a small amount of iron in the SA-Fe-NC can deliver extremely superior specific activity in PMS activation and develops a promising catalytic oxidation system toward actual environmental cleanup.