Efficient Activation of Peroxymonosulfate for Degradation of Rhodamine B by Anchoring CoFe 2 O 4 on MoS 2 Nanoflower-Modified Biochar

In this study, CoFe 2 O 4 anchored by MoS 2 modified biochar (CoFe 2 O 4 @MoS 2 –BC) was synthesized using a hydrothermal approach and utilized to activate peroxymonosulfate (PMS) to degrade rhodamine B (RhB). The effects of pH value, catalyst and PMS dosage, RhB concentration, and coexisting compounds were systematically investigated. Within 7 min, CoFe 2 O 4 @MoS 2 –BC achieved a removal rate of 99.63% for 100 mg·L –1 RhB. The outstanding stability and environmental compatibility of CoFe 2 O 4 @MoS 2 –BC was verified by cycling and metal ion leaching experiments. The contribution of 1 O 2, SO 4 •–, • OH, and • O 2 – in the degradation procedure was revealed by quenching experiments, among which 1 O 2 was the predominant active species. Electrochemical characterization indicated that CoFe 2 O 4 @MoS 2 –BC exhibited enhanced current density, redox activity, and superior electron transfer capability. Comprehensive characterization analysis and experimental data revealed that the high efficiency of CoFe 2 O 4 @MoS 2 –BC was attributed to Co 2+ /Co 3+, Fe 2+ /Fe 3+, and Mo 4+ /Mo 6+ redox cycling on the CoFe 2 O 4 @MoS 2 –BC surface. The cycles of Co 2+ /Co 3+ and Fe 2+ /Fe 3+ were enhanced by Mo, while unsaturated S increased the reactivity of Mo, thereby accelerating the redox of metal ions; oxygen vacancies (O v ) enhance the mobility of surrounding oxygen ions mobility and promoted the conversion from lattice oxygen (O lat ) to reactive oxygen species (O*), thereby activating PMS effectively. This research is expected to provide innovative insights that will inform the design and development of excellent activity and stability of heterogeneous metal-based catalysts.