Phase manipulation of MoS₂ from thermodynamically stable 2H phase to the unstable but more reactive 1T phase represents a crucial strategy for improving the reactivity in many reactions. The widely adopted wet chemistry approach uses intercalating entities especially alkali metal ions to achieve the phase transition; however, these entities are normally inert for the target reaction. Here, we describe the first use of iron atoms for the intercalation of 2H-MoS₂ layers, driving the partial transition from 2H to 1T phase. Interestingly, in the peroxymonosulfate (PMS)-based Fenton-like reactions, the interlayered confinement of Fe atoms not only activates the inert basal plane, but also adds more reactive Fe sites for the formation of metal-PMS complex as primary reactive species for pollutant removal. In the degradation of a model pollutant carbamazepine (CBZ), the Fe-intercalated MoS₂ exhibits a first order rate constant 13.3 times higher than 2H-MoS₂. This strategy is a new direction for manipulating the phase composition and boosting the catalytic reactivity of MoS₂-based catalysts in various scenarios, including environmental remediation and energy applications.

In the pursuit of heterogeneous catalysts with high reactivity, metal organic framework (MOF) nanomaterials have received tremendous attentions. However, many MOF catalysts especially Fe-based MOFs need to be utilized immediately after synthesis or being activated using high temperature, because of the easy loss of reactivity in humid environments resulting from the occupation of active Fe sites by water molecules. Here, we describe an inspiring strategy of growing MIL-101-Fe nanoparticles inside the three-dimensional confined space of graphene aerogel (GA), generating shapeable GA/MIL-101-Fe nanocomposite convenient for practical use. Compared to MIL-101-Fe, GA/MIL-101-Fe as catalyst demonstrates much higher reactivity in Fenton-like reaction, attributing to smaller MIL-101-Fe particle size, presence of active Fe(II) sites, and abundant defects in GA. Strikingly, the weakly hydrophobic nature of the composite greatly inhibits the loss of catalytic reactivity after being stored in humid air and accelerates the recovery of reactivity in mild temperature, by resisting the entrance of water molecules and helping to exclude water molecules. This work demonstrates that a delicate design of nanocomposite structure could not only improve the reactivity of the catalytic component, but also overcome its intrinsic drawback by taking advantage of the properties of host. We hope this functional nanoconfinement strategy could be extended to more scenarios in other fields.