Axial g-C3N4 coordinated iron(III) phthalocyanine mediated ultra-efficient peroxymonosulfate activation for high-valent iron species generation

• Published in: Applied catalysis. A, General General, 2022-07, Vol.641, p.118679, Article 118679
• Main Authors: Ding, Yan, Cui, Kangping, Liu, Xueyan, Li, Chen-Xuan, Guo, Zhi, Cui, Minshu, Chen, Yihan
• Format: Article
• Language: English
• Subjects: Axial coordination; Carbon nitride; Catalysts; DFT calculations; Dyes; Electron transfer; High-valent iron-oxo species; Iron; Ligands; Molecular orbitals; Oxidation; Peroxymonosulfate activation; Pollutants; Two-electron transfer
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2022.118679

Herein, a new axial g-C3N4 coordinated iron(III) phthalocyanine (FeP/CN) was fabricated for peroxymonosulfate (PMS) activation. Around 100% degradation of acetaminophen (AP), 2,4-dichlorophenol (2,4-DP), sulfadiazine (SDZ), and methyl orange (MO) (30 mg L-1) were achieved within 20 min by adding 0.02 g L-1 FeP/CN5 (3.62 wt% Fe) and 0.2 mM PMS. High-valent iron-oxo species (FeIV=O) was demonstrated as the main reactive species, which mediated a two-electron transfer process with pollutants. Characterizations and computational analysis revealed that the axial g-C3N4 ligand provided Fe(III) coordination environments to generate FeIV=O species directly through PMS activation, and increased the reactivity of the FeIV=O species in pollutants oxidation due to the narrowed HOMO-LUMO gap. Besides, small displacement of Fe atom (0.23 Å) from the macrocycles plane due to the axial g-C3N4 ligand decreased the iron demetalization rate from 3.54% to 0.28% in the catalyst/PMS system. This work offered an excellent strategy to design high-efficiency catalysts for FeIV=O generation. [Display omitted] •Axial g-C3N4 anchored iron phthalocyanine was successfully fabricated.•High-valent iron-oxo species was the main reactive species for the oxidation.•PMS dosage was greatly saved due to the two-electron transfer process of FeIV=O.•Five ligated Fe(III)-N moieties mediated the generation of FeIV=O directly.•The reactivity of FePc was significantly elevated by the axial ligand of g-C3N4.