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

Commercial molybdenum carbide (Mo2C) and ferrous iron (Fe2+) were investigated for the first time to co-catalyze the activation of H2O2 for the treatment of organic contaminants. Compared with traditional Fenton process, the presence of Mo2C decomposed hydrogen peroxide (H2O2) more effectively and accelerated the conversion of Fe3+/Fe2+. The Rhodamine B (RhB) degradation rate constant in Mo2C/Fe2+/H2O2 reached appropriately three times that in Fe2+/H2O2, and the co-catalytic reactivity of Mo2C was significantly higher than that of MoS2. In addition, (MoC)-C-2/Fe2+/H2O2 exhibited a board effective pH range of 2.8-8.8, and four-cycle experiments confirmed the stability and reusability of Mo2C. The results of X-ray photoelectron spectroscopy (XPS) indicated that Mo(II) and Mo(IV) played major roles in Fe3+ reduction. Electron Paramagnetic Resonance analysis and quenching experiments demonstrated that hydroxyl radical (.OH), superoxide anion radical (O-2(-)) and singlet oxygen radical (O-1(2)) were all involved in Mo2C/Fe2+/H2O2. Particularly, Mo2C/Fe2+/H2O2 signifi-cantly enhanced the generation of .OH and O-1(2) in comparison to Fe2+/H2O2. 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 Mo2C co-catalyzed Fenton process for rapid and efficient abatement of organic contaminants.

Automated summary

Commercial molybdenum carbide (Mo2C) and ferrous iron (Fe2+) were investigated as co-catalysts for the activation of H2O2 in the treatment of organic contaminants. The presence of Mo2C effectively decomposed H2O2 and accelerated the conversion of Fe3+/Fe2+ compared to traditional Fenton process. Mo2C/Fe2+/H2O2 exhibited a significantly higher catalytic reactivity than MoS2, and the degradation rate constant of Rhodamine B in Mo2C/Fe2+/H2O2 was three times higher than that in Fe2+/H2O2. XPS analysis showed that Mo(II) and Mo(IV) played major roles in Fe3+ reduction, and EPR analysis confirmed the involvement of .OH, O-2(-), and O-1(2) in Mo2C/Fe2+/H2O2. ECOSAR toxicity assessment revealed a decrease in the toxicity of RhB degradation products after treatment. Overall, this study presents a promising Mo2C co-catalyzed Fenton process for efficient abatement of organic contaminants.