Fe–nitrogen–doped carbon with dual active sites for efficient degradation of aromatic pollutants via peroxymonosulfate activation

Fenton-like catalysis has received much attention as the promising technology for organic pollutant degradation, whereas it suffers from low atomic utilization, poor catalysts durability and difficult after-treatment to hamper the catalytic oxidation activity. Herein, a Fe– and nitrogen-codoped carbon (Fe–N–C) originated from nanocellulose-based hydrochar, nitrogen source, and iron salt precursor was developed for improved PMS activation and identification of exclusive role of each species. The catalyst formed with interconnected bamboo-shaped 3D tubular structures and high Fe-doping level (up to ~9.0 wt%) not only realized excellent efficiencies in oxidative degradation of various aromatic pollutants, but was also endowed with high durability and stability toward PMS activation. Compared with that of the control catalysts only comprising either C–N network or supported Fe nanoparticles (Fe–C) with FeIV–oxo complex sites, the co-existent active sites of Fe–N configuration and atomic Fe cluster in Fe–N–C could simultaneously improve the graphitization degree, and act as a “support” for constructing the stable structure. It is likely that the coordinated Fe–N formed with annealing process is devoted to decompose PMS by radical generation for pollutants degradation via a radical oxidation process; while the enhanced C–N bonded with graphitic N contribute to produce 1O2 through the nonradical processes interacted with PMS. This Fe–N–C/PMS-coupled process provided a designed strategy to construct the highly active and stable metal-nitrogen-codoped hydrothermal carbons, and deepened insights on structure-activity-stability relationship for persulfate-based environmental remediation.