Catalytic Ozone Decomposition of Methylene Blue by MoS2 and Chitosan-Derived N-Doped Carbon Co-Modified CoFe-LDO

In this work, CoFe-layered double metal oxide (CoFe-LDO) was obtained by a co-precipitation-calcination route using CoFe-layered double metal hydroxide (CoFe-LDH) as precursor material, and then MoS 2 and chitosan-derived N-doped carbon co- modified CoFe-LDO composite catalyst (MoS 2 @CoFe-LDO/NCS) was prepared. This material was characterized by SEM, EDS, FTIR, XRD and XPS, and was synthesized to catalyze ozonation for the degradation of methylene blue (MB). The influence of CoFe-LDO dosage, O 3 flow rate, initial MB concentration, catalyst dosage, initial pH and coexisting compounds on MB removal efficiency were systematically investigated. The decomposition efficiency of 50 mg/L MB by 10%MoS 2 @CoFe-LDO/NCS reached 96.47% within 8 min under the conditions of 10% CoFe-LDO dosage (CoFe -LDO:CS), pH = 6.8, catalyst dosage of 0.4 g/L, Ozone flow rate of 1.87 mg/(L⋅min) and 25 °C. Stability tests and metal ion leaching experiments confirmed the excellent chemical stability and environmental compatibility of 10%MoS 2 @CoFe-LDO/NCS. Electrochemical characterization showed that 10%MoS 2 @CoFe-LDO/NCS possessed enhanced current density, redox activity and excellent electron transfer capability. Quenching experiments revealed that 1 O 2 , O 2 ∙ − and ∙ OH contributed to the MB degradation process, with O 2 ∙ − confirmed as the dominant reactive species.