Slow-released corrosive charge of zerovalent iron rendered superior Fenton-like catalysis: the tailored electron generation, transfer and utilization derived from spatial MoS2 encapsulation

Abstract

Nano zerovalent iron (nZVI) has attracted great interest for the heterogeneous Fenton-like catalysis in environmental remediation due to its high capacity and low cost. However, toxicity and pollution risks arising from the rapid chemical corrosion in the oxygenated aqueous medium largely limit its more practical applications. In this study, the two-dimensionally defective MoS₂ was introduced as the key spatial protector to tailor the electron generation, transfer pathway and utilization efficiency of corrosive charge released from the chemical corrosion of nZVI in aqueous medium during reactions. We rationally designed and controllably prepared the nZVI@MoS₂ hybrid, in which MoS₂ spatially encapsulated nZVI to form the core-shell structure. Fenton-like catalysis on nZVI@MoS₂ produced reactive species to decompose refractory pollutants. Inner nZVI core transferred electrons to PMS through outer MoS₂ shell to activate PMS. Moreover, the MoS₂ shell promoted the Fe(II)/Fe(III) redox-cycling on nZVI and slowed down chemical corrosion of metallic core for superior and sustainable catalysis. Quenching and electron paramagnetic resonance tests indicated the involved hydroxyl radical, sulfate radical, superoxide radical and singlet oxygen with good reusability. Our work provided a new strategy to refine the environmental potential of nZVI benchmark with high industrial importance by two-dimensional transition metal sulfides for the superior environmental Fenton-like catalysis.