ReaxFF Force Field Development and Application for Toluene Adsorption on MnMO_x (M = Cu, Fe, Ni) Catalysts

Abstract

In numerous studies, the application of the molecular dynamics scheme based on the reactive force field (ReaxFF) method has been proven effective in modeling the catalytic behavior of metal–organic compounds. Recently, this method has been successfully applied for M x O y (M = Cu, Fe, Mn, Ni) transition-metal oxides. Yet, bimetallic metal oxides of the type MnMO x (M = Cu, Fe, Ni) were also present in the experimental system but could not be modeled since not all of the force field parameters were available at the time. To bridge this gap, the force field for modeling bimetallic metal oxides had to be developed. Here, we establish the needed force field parameter sets (namely, Cu/Mn/O, Fe/Mn/O, and Ni/Mn/O) and apply them to the problem of toluene adsorption on bimetallic oxide catalyst surfaces to verify their validity. Each training set consisted of at least 10 crystal structures containing at least Cu–Mn–O, Fe–Mn–O, or Ni–Mn–O atoms in contact obtained from the available structure databases. The parameter training has been done using the in-home-compiled version of the ReaxFF code. After training the force fields for geometry reproduction, the parameters were refined using the optimization by atom charges, comparing the ReaxFF values to those obtained for the respective structures using periodic crystal density functional theory (DFT) codes. The as-developed force fields were then applied to the process of toluene adsorption/degradation on MnMO x catalysts. Results obtained show agreement with previous experimental expectations, although some remarks are given since the initially presumed crystal structure of bimetallic oxide Mn 1– x M x O y crystallites may still have an impact on theoretical predictions. The presented are, to the best of the authors’ knowledge, the first applications of the ReaxFF approach to the Mn–(Cu|Fe|Ni)–O–C–H interaction.

The formation mechanism of Sc-based metallofullerenes: a molecular dynamics simulation study

“…Therefore, the development and testing of force field parameters often precedes ReaxFF MD simulations. 32–42…”

“…Therefore, the development and testing of force field parameters often precedes ReaxFF MD simulations. [32][33][34][35][36][37][38][39][40][41][42] To the best of our knowledge, no reactive force fields tailored for Sc exist to date. We used the parameters of Zr 43 to form the initial parameter set.…”

Unraveling the Interplay between Quantum Transport and Geometrical Conformations in Monocyclic Hydrocarbons’ Molecular Junctions

“…To simulate the rupture–formation cycles of the gold nanowire with the target molecules, we used the LAMMPS code − with a reactive force-field (ReaxFF) potential, , which reproduces the single-molecule junctions , and mechanical, catalytic behavior of metal–organic compounds. , …”

“…38,39 To simulate the rupture−formation cycles of the gold nanowire with the target molecules, we used the LAMMPS code 40−42 with a reactive force-field (ReaxFF) potential, 43,44 which reproduces the single-molecule junctions 45,46 and mechanical, catalytic behavior of metal−organic compounds. 47,48 The simulated nanowire is oriented along the (001) crystallographic direction and has been created with an area of narrower cross-section (≈17 × 17 × 25 Å 3 ) where rupture will take place. 49 In this area of constriction, we place four molecules on each of the four square crystallographic facets of the gold nanowire (see the "Input" panels in Figure 3); hence, 16 molecules are deposited in total for each initial condition.…”

optimade-python-tools: a Python library for serving and consuming materials data via OPTIMADE APIs

“…Database : The largest open access collection of experimental crystal structures 49 . It is widely used by the scientific community to explore different material categories such as superconductors 21 , metal-organic frameworks 11 , high entropy alloys 118 , organic molecules 17 as well as for conformer sampling 84 or custom force field generation 45 . Having a set of experimental structures readily available under the same format as is required for computational materials research is highly beneficial since these structures serve as initial points for material property calculations 127 or for the search of new materials 101 .…”