Accelerated Fe3+/Fe2+ cycle in Mo2C-based Fe catalyst to promote peroxymonosulfate activation

The harmful impact of organic pollutants on aquatic ecosystems underscores the pressing need for effective remediation. While activating peroxymonosulfate (PMS) with Fe catalyst offers a promising approach for eliminating these pollutants, its widespread use is hindered by the sluggish regeneration of Fe2+ from Fe3+. Here, this study demonstrates for the first time that combining an Fe catalyst with Mo2C (Fe-Mo2C) enhances the Fe³⁺/Fe2⁺ cycle, thereby improving PMS activation. The Fe-Mo2C/PMS system achieved near-complete degradation of carbamazepine (CBZ) within only 8 min, with an impressive observed rate constant (kobs) of up to 0.624 min−1, about 15 times greater than that of Fe-C catalyst. It also exhibits the capability to degrade a broad range of common antibiotics, phenols, and dye-like organic compounds. Through electron paramagnetic resonance (EPR) analysis and quenching experiments, it was verified that hydroxyl radicals (·OH), sulfate radicals (SO4·-), singlet oxygen (1O2), and superoxide radicals (·O2−) species during the reaction, with the former three serving as the primary active species. These findings offer a hopeful avenue for the systematic development and enhancement of catalysts specifically designed to efficiently remediate organic pollutants in wastewater. [Display omitted] •A novel Fe-Mo2C catalyst was synthesized using a coprecipitation and calcination method.•The introduction of Mo2C accelerated the Fe3+/Fe2+ cycle for peroxymonosulfate activation.•The catalytic system achieved a notable rate constant of 0.624 min−1 for carbamazepine removal.•SO4·-, ·OH, 1O2 and ·O2− were identified as the primary active species.