Transition metal dichalcogenides (TMDs) have recently received a lot of attention because they exhibit thickness- and composition-dependent properties. In particular, TMDs have direct band gaps when bulk TMDs with indirect band gaps reach monolayers, resulting in intriguing chemical, electrical, and optical properties. One noteworthy feature of the TMD nanosheets from the structural point of view is that they can possess chalcogen defects that are known to be active sites. An oxidation-reduction process, which occurs in radical scavenging, can also be influenced by these reactive sites, and its designated energy barrier can be provided by the adjacent atoms across the surface of the TMD nanosheets, which can play a decisive role in enhancing the radical scavenging ability. Herein, we introduce a TMD-based antioxidation platform having excellent radical scavenging performance as well as structural stability under harsh storage conditions. The key to this approach is to fabricate a stable suspension of TMD nanosheets with an ultrathin platelet configuration that exhibits the defect-mediated one-step hydrogen atom transfer. Accordingly, we fabricated the stable suspension of TMD nanosheets by enveloping them with a monolayer of an amphiphilic diblock copolymer, poly(ε-caprolactone)-b-poly(ethylene oxide) (PCL-b-PEO). We subsequently characterized the optical and structural properties of PCL-b-PEO-enveloped TMD nanosheets. Finally, we demonstrated that the TMD nanosheets fabricated in our study showed outstanding radical scavenging activities in aqueous media by using ABTS assay (2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) under a variety of storage conditions. These characteristics highlight that the TMD nanosheets fabricated in this study can be used as promising radical scavengers, encouraging the further investigation of these functional TMD materials for biological applications.

Outstanding radical scavenging of transition metal dichalcogenide nanosheets via defect-mediated one-step hydrogen atom transfer in aqueous media

256th National Meeting (2018)

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