Accelerated Fe(III)/Fe(II) cycle for rapid elimination of Rhodamine B by a novel Mo2C co-catalytic Fe2+/H2O2 system

Commercial molybdenum carbide (Mo 2 C) and ferrous iron (Fe 2+ ) were investigated for the first time to co-catalyze the activation of H 2 O 2 for the treatment of organic contaminants . Compared with traditional Fenton process, the presence of Mo 2 C decomposed hydrogen peroxide (H 2 O 2 ) more effectively and accelerated the conversion of Fe 3+ /Fe 2+ . The Rhodamine B (RhB) degradation rate constant in Mo 2 C/Fe 2+ /H 2 O 2 reached appropriately three times that in Fe 2+ /H 2 O 2 , and the co-catalytic reactivity of Mo 2 C was significantly higher than that of MoS 2 . In addition, Mo 2 C/Fe 2+ /H 2 O 2 exhibited a board effective pH range of 2.8–8.8, and four-cycle experiments confirmed the stability and reusability of Mo 2 C. The results of X-ray photoelectron spectroscopy (XPS) indicated that Mo(Ⅱ) and Mo(IV) played major roles in Fe 3+ reduction. Electron Paramagnetic Resonance analysis and quenching experiments demonstrated that hydroxyl radical (·OH), superoxide anion radical (O 2 − ) and singlet oxygen radical ( 1 O 2 ) were all involved in Mo 2 C/Fe 2+ /H 2 O 2 . Particularly, Mo 2 C/Fe 2+ /H 2 O 2 significantly enhanced the generation of ·OH and 1 O 2 in comparison to Fe 2+ /H 2 O 2 . Moreover, toxicity assessment analysis by ECOSAR suggested that the toxicity of most degradation products of RhB decreased after treatment. Overall, this study offers a promising Mo 2 C co-catalyzed Fenton process for rapid and efficient abatement of organic contaminants.