Engineering the low-coordinated single cobalt atom to boost persulfate activation for enhanced organic pollutant oxidation

• Published in: Applied catalysis. B, Environmental Vol. 303; p. 120877
• Main Authors: Liang, Xiaoying, Wang, Di, Zhao, Zhiyu, Li, Tong, Chen, Zhenhuan, Gao, Yaowen, Hu, Chun
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2022; Elsevier BV
• Subjects: Active radicals; Biodegradation; Bisphenol A; Catalysts; Cobalt; Coordination number; Coordination numbers; Durability; Electron density; Electron paramagnetic resonance; Electron spin resonance; Nitrogen; Oxidation; Persulfate conversion; Pollutants; Single-atom catalysts; Wastewater; Wastewater treatment; Persulfate conversion; Single-atom catalysts; Coordination number; Electron density; Active radicals
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2021.120877

Two atomically dispersed cobalt catalysts with different nitrogen coordination numbers (denoted as CoSA-Nx-C) were synthesized and firstly compared to activate peroxydisulfate (PDS) for bisphenol A (BPA) degradation. Theoretical calculations unveiled that lowering the CoN coordination number from four to three can apparently increase the electron density of the single Co atom in CoSA-N3-C to enhance PDS conversion. The low-coordinated CoSA-N3-C with CoN3 coordination structure displays a high specific activity of 0.067 L min1 m2, which is 1.31 times greater than that of CoSA-N4-C with normal CoN4 configuration (0.051 L min1 m2) in PDS activation. Electron paramagnetic resonance (EPR) measurements and quenching tests confirmed the primary role of sulfate radical (SO4•−) in BPA oxidation over CoSA-N3-C with PDS. Moreover, CoSA-N3-C delivers favorable durability for PDS activation and potential practicability for realistic wastewater remediation. These findings provide a novel and useful avenue to coordination number modulation of SACs for wider environmental applications. [Display omitted] •Single-atom Co catalyst was firstly applied in peroxydisulfate (PDS) activation.•Lowering coordination number can enhance the electron density of single Co atom.•Single-atomic CoN3 sites deliver higher affinity to PDS than CoN4 centers.•Low-coordinated CoSA-N3-C outperforms CoSA-N4-C with CoN4 sites in PDS conversion.•CoSA-N3-C shows good stability and applicability in actual wastewater remediation.