Longitudinal unzipping of 2D transition metal dichalcogenides

Abstract

Unzipping of the basal plane offers a valuable pathway to uniquely control the material chemistry of 2D structures. Nonetheless, reliable unzipping has been reported only for graphene and phosphorene thus far. The single elemental nature of those materials allows a straightforward understanding of the chemical reaction and property modulation involved with such geometric transformations. Here we report spontaneous linear ordered unzipping of bi-elemental 2D MX2 transition metal chalcogenides as a general route to synthesize 1D nanoribbon structures. The strained metallic phase (1T′) of MX2 undergoes highly specific longitudinal unzipping owing to the self-linearized oxygenation at chalcogenides. Stable dispersions of 1T′ MoS2 nanoribbons with widths of 10–120 nm and lengths up to ~4 µm are produced in water. Edge abundant 1T′ MoS2 nanoribbons reveal the hidden potential of idealized electrocatalysis for hydrogen evolution reactions at a competitive level with the precious Pt catalyst.

Review of strategies toward the development of alloy two-dimensional (2D) transition metal dichalcogenides

“…, valence band maximum to the conduction band ( Fan et al., 2017 ; Onofrio et al., 2017 ). Similar phenomena were observed for MX 2 lattice where phase transformation of MX 2 from 2H to 1T is also supported by experimental justification by synthesis of Li intercalation using powder metallurgy route ( Figure 2 C) ( Padmajan Sasikala et al., 2020 ). For NbX 2 and TaX 2 , no such phase transfer occurs, but their Fermi level showed moving into a gap that is not suitable for electron transport ( Fan et al., 2017 ).…”

“…Doping of V in MoS 2 was reported as poor p-type conduction behavior than WS 2 and WSe 2 as the doped sample was determined to have a degenerate state ( Figure 2 B) ( Li et al., 2021 ; Williamson et al., 2019 ). Doping of Fe in WS 2 lattice resulted in n-type with defect coupling and lattice distortion similar to Mo-doped WS 2 lattice ( Padmajan Sasikala et al., 2020 ). Doping of Fe in MoTe 2 lattice-induced spins on nearby Te and Mo atoms is parallel to dopants.…”

Epitaxial growth of inch-scale single-crystal transition metal dichalcogenides through the patching of unidirectionally orientated ribbons

“…For instance, one-dimension (1D) monolayer MoS 2 ribbon is predicted to possess novel properties such as metallic edge states 4 , 1D confined plasmons 5 , ferromagnetic behaviors 6 , etc. Besides, it can present improved catalytic property in hydrogen evolution reaction (HER) due to the abundant active edge sites 7 , and more importantly, maintained high carrier mobility 8 . So far, the fabrication of monolayer TMDs ribbons has largely depended on micro-nanofabrication approaches, by using electron beam or optical lithography patterning techniques 9 .…”

Active Site Engineering on Two-Dimensional-Layered Transition Metal Dichalcogenides for Electrochemical Energy Applications: A Mini-Review

“…Although the surface of 2D-layered materials with minimal roughness and dangling bonds can be regarded as basal planes, which are useful for electrical applications, the catalytic activity of 2D-layered material basal planes is poor. The catalytic activity is basically located at the edge sites of 2D-layered materials because more dangling bonds can trigger more catalysis [28,29]. Therefore, a new strategy has been proposed to achieve controllable defect engineering in MoS 2 ultrathin nanosheets for creating more active edge sites [30].…”