Stabilization of 1T-MoS₂ Sheets by Imidazolium Molecules in Self-Assembling Hetero-layered Nanocrystals

Influence of noncovalent intramolecular and host–guest interactions on imatinib binding to MoS2 sheets: a PXRD/DFT study

The revealed pattern of imatinib drug binding to MoS2 sheets is promising for the combined exploitation of these species for therapeutic purposes.

Self-Assembly of MoS2 Monolayer Sheets by Desulfurization

Self-assembled structures of two-dimensional (2D) materials exhibit novel physical properties distinct from those of their parent materials. Herein, the critical role of desulfurization on the self-assembled structural morphologies of molybdenum disulfide (MoS₂) monolayer sheets is explored using molecular dynamics (MD) simulations. MD results show that there are differences in the atomic energetics of MoS₂ monolayer sheets with different desulfurization contents. Both free-standing and substrate-hosted MoS₂ monolayer sheets show diversity in structural morphologies, for example, flat plane structures, wrinkles, nanotubes, and folds, depending on the desulfurization contents, planar dimensions, and ratios of length to width of MoS₂ sheets. Particularly, at the critical desulfurization content, they can roll up into nanotubes, which is in good agreement with previous experimental observations. Importantly, these observed differences in the molecular structural morphologies between free-standing and substrate-hosted MoS₂ monolayer sheets can be attributed to interatomic interactions and interlayer van der Waals interactions. Furthermore, MD results have demonstrated that the surface-driven stability of MoS₂ structures can be indicated by the desulfurization contents on one surface of MoS₂ monolayer sheets, and the self-assembly of MoS₂ monolayer sheets by desulfurization can emerge to adjust their surface-driven stability. The study provides important atomic insights into tuning the self-assembling structural morphologies of 2D materials through defect engineering in the future science and engineering applications.

Phase Engineering of Transition Metal Dichalcogenides with Unprecedentedly High Phase Purity, Stability, and Scalability via Molten-Metal-Assisted Intercalation

The crystalline phase of layered transition metal dichalcogenides (TMDs) directly determines their material property. The most thermodynamically stable phase structures in TMDs are the semiconducting 2H and metastable metallic 1T phases. To overcome the low phase purity and instability of 1T-TMDs, which limits the utilization of their intrinsic properties, various synthesis strategies for 1T-TMDs have been proposed in phase-engineering studies. Herein, a facile and scalable synthesis of 1T-phase molybdenum disulfide (MoS₂ ) via the molten-metal-assisted intercalation (MMI) approach is introduced, which exploits the capillary action of molten potassium and the difference between the electron affinity of MoS₂ and the ionization potential of potassium. Highly reactive molten potassium metal can readily intercalate into the MoS₂ interlayers, inducing an efficient phase transition from the 2H to 1T crystal structure. The ionic bonding between the intercalated potassium and sulfur lowers the energy barrier of the 1T-phase transition, enhancing the phase stability of the 1T crystals. Owing to the high purity and stability of the 1T phase, the electrocatalytic performance for the hydrogen evolution reaction is significantly higher in 1T-MoS₂ (MMI) than in 2H-MoS₂ and even in 1T-MoS₂ synthesized using n-butyllithium.

Probing Hydrogen-Bonding Properties of a Negatively Charged MoS2 Monolayer by Powder X-ray Diffraction and Density Functional Theory Calculations

The contributions of various noncovalent interactions in stabilization of the assembled and delaminated MoS₂-hexamethylenetetramine (HMTA)-layered compound resulted from the assembly of protonated HMTA molecules and negatively charged 1T-MoS₂ monolayers have been considered on the basis of powder X-ray diffraction pattern modeling, density functional theory calculations, and atoms in molecules quantum theory analysis. The structure with HMTA cations involved in NH···S bonding with MoS₂ layers was concluded to be more advantageous than the alternative one with NH···N bonding between the cations. Delamination was demonstrated to essentially influence the hierarchy of interactions and leads to significant strengthening of the NH···S hydrogen bond established between HMTA and the MoS₂ monolayer surface. The method applied in this study for evaluation of the monolayer MoS₂ properties on the basis of the 3D structure of the MoS₂-organic compound is expected to be helpful to gain insights into the interactions occurring in many MoS₂-based systems.

Nanostructured tungsten sulfides: insights into precursor decomposition and the microstructure using X-ray scattering methods

The entire path from a thiotungstate precursor via its decomposition intermediate to nanosized WS₂ with heavy stacking disorder is traced using various X-ray scattering methods.

Amidoximated poly(vinyl imidazole)-functionalized molybdenum disulfide sheets for efficient sorption of a uranyl tricarbonate complex from aqueous solutions

A new method is developed for effective uranium(vi) sorption from aqueous solution through amidoximated poly(vinyl imidazole)-functionalized MoS₂ sheets.

Methyl-functionalized MoS2 nanosheets with reduced lattice breathing for enhanced pseudocapacitive sodium storage

Methyl-functionalized MoS₂ (M-MoS₂) nanosheets have been synthesized via a facile second solvothermal method.

Electrostatic Origin of Stabilization in MoS2-Organic Nanocrystals

Negatively charged molybdenum disulfide layers form stable organic-inorganic layered nanocrystals when reacted with organic cations in solution. The reasons why this self-assembly process leads to a single-phase compound with a well-defined interlayer distance in given conditions are, however, poorly understood to date. Here, for the first time, we quantify the interactions determining the cation packing and stability of the MoS₂-organic nanocrystals and find that the main contribution arises from Coulomb forces. The study was performed on the series of new layered compounds of MoS₂ with naphthalene derivatives, forming several distinct phases depending on reaction conditions. Starting with structural models derived from powder X-ray diffraction data and TEM, we evaluate their cohesion energy by modeling layer separation with periodic PW-DFT-D calculations. The results provide a reliable approach for estimation of the stability of MoS₂-based heterolayered compounds.