Mo Atom Rearrangement Drives Layer-Dependent Reactivity in Two-Dimensional MoS₂.

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• Two-dimensional (2D) materials enable atomic-level control of chemical reactions.
• Understanding structural transformations during reactions in 2D materials is crucial but underexplored.

Purpose of the Study:

• Investigate the layer-dependent chemical reactivity of molybdenum disulfide (MoS2) during nitridation.
• Elucidate the role of atomic rearrangement in governing reactivity.

Main Methods:

• Atomic-resolution transmission electron microscopy (TEM) for product imaging.
• Local conductivity mapping.
• Analysis of nitridation atomic substitution reactions in MoS2.

Main Results:

• MoS2 chemical reactivity decreases with fewer layers, with monolayer MoS2 being least reactive.
• Molybdenum nitride (MoN) nanonetworks form, showing increased continuity with higher MoS2 layer numbers.
• Reactivity is linked to the energy cost of Mo atom diffusion for forming stable MoN lattices.

Conclusions:

• Lattice rearrangement significantly influences chemical reactivity in 2D materials.
• MoS2 layer number dictates reactivity through atomic migration and phase stability.
• 2D materials are promising platforms for fundamental materials chemistry research.