Development and Application of a ReaxFF Reactive Force Field for Ni-Doped MoS₂

Abstract

The properties of MoS2 can be tuned or optimized through doping. In particular, Ni doping has been shown to improve the performance of MoS2 for various applications, including catalysis and tribology. To enable investigation of Ni-doped MoS2 with reactive molecular dynamics simulations, we developed a new ReaxFF force field to describe this material. The force field parameters were optimized to match a large set of density functional theory (DFT) calculations of 2H-MoS2 doped with Ni, at four different sites (Mo-substituted, S-substituted, octahedral intercalation, and tetrahedral intercalation), under uniaxial, biaxial, triaxial, and shear strain. The force field was evaluated by comparing ReaxFF- and DFT-relaxed structural parameters, the tetrahedral/octahedral energy difference in doped 2H, energies of doped 1H and 1T monolayers, and doped 2H structures with vacancies. We demonstrated the application of the force field with reactive simulations of sputtering deposition and annealing of Ni-doped MoS2 films. Results show that the developed force field can successfully model the phase transition of Ni-doped MoS2 from amorphous to crystalline. The newly developed force field can be used in subsequent investigations to study the properties and behavior of Ni-doped MoS2 using reactive molecular dynamics simulations.

Experimental Studies on TiO2 NT with Metal Dopants through Co-Precipitation, Sol–Gel, Hydrothermal Scheme and Corresponding Computational Molecular Evaluations

“…Furthermore, a modern technique for simulating Ni-doped MoS 2 to understand the effect of doping was found to be the reactive force field (ReaxFF), connecting quantum mechanical and experiments [188]. This makes TNT metal doping using ReaxFF a particularly useful tool to understand the dynamics of doping research [189].…”

Electrodeposited MoxSyOz/Ni Tribological Coatings

“…Electrodeposition is a promising low-cost alternative coating method for complex geometries that offers similar flexibility in compositional and microstructural control to PVD techniques yet has the added ability to deposit amorphous and sulfur-rich coatings, both of which are difficult to achieve with PVD. Amorphous PVD coating microstructures are deposited by co-sputtering with metal/metal-oxide dopants, such as nickel, , or by the inclusion of oxygen. , Both metal-doped and high oxygen-containing coatings are capable of achieving ultralow friction (μ < 0.05) and improved wear resistance compared to pure MoS 2 films due to densification. Depending on the electrodeposition parameters, an aqueous solution of MoS 4 2– results in MoS 3 , an amorphous material that is rarely used as a solid lubricant yet has been shown to provide low friction and wear due to the formation of MoS 2 under mechanical shear.…”