Investigating Grain Boundary Structures and Energetics of Rutile with Reactive Molecular Dynamics

Abstract

Determining quantitative grain boundary (GB) energies as a function of microscopic orientation parameters is essential in order to understand the population of boundaries present in polycrystalline ceramics and films, and the physical properties that result from these boundaries. Here, we investigate the use of two reactive potentials, COMB3 and ReaxFF, to predict free surface and grain boundary structures and energies in the TiO 2 rutile system, and compare these results against previously reported ab initio surface and interfacial energies. We demonstrate reactive MD potentials to be generally capable of reproducing key features anticipated for GB structures and energetics, including relative GB and surface energy, charge distributions and potential for different polar and nonpolar terminations, and energy cusps at low-energy interfaces (e.g., coherent twin boundaries, coherent site lattice boundaries). This work establishes the foundation for further use of reactive MD to simulate libraries of oxide GBs and dynamic processes occurring along those GBs.

Metastability at Defective Metal Oxide Interfaces and Nanoconfined Structures

“…DFT can be used to model grain boundaries, dislocations, and polycrystalline interfaces, however, the number of atoms needed to be simulated is significantly increased from the pure bulk case and interatomic potentials might become more appropriate, as shown for TiO2 [70][71][72] .…”

Facet-Dependent Photocatalytic Behavior of Rutile TiO2 for the Degradation of Volatile Organic Compounds: In Situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy and Density Functional Theory Investigations

“…It is crucial to emphasize that extensive research has been dedicated to investigating the surface structure of single-crystal TiO 2 particles due to their significant influence on their chemical reactivity. The distinctive atomic coordination environments and variations in energy levels across various exposed crystal surfaces result in significant divergences in the catalytic performance of these materials . The performance disparities emphasize the pivotal impact of specific crystal facets on the catalytic behavior of TiO 2 -based catalysts.…”

“…The distinctive atomic coordination environments and variations in energy levels across various exposed crystal surfaces result in significant divergences in the catalytic performance of these materials. 5 The performance disparities emphasize the pivotal impact of specific crystal facets on the catalytic behavior of TiO 2 -based catalysts. Grasping these surface structure−activity relationships is essential for tailoring and optimizing the photocatalytic system design, enhancing efficiency in various applications.…”

A Cumulative Approach to Crystalline Structure Characterization in Atomistic Simulations

“…Nevertheless, the PCNP is better at distinguishing bulk features while being less optimal for surface feature detection. Applications such as the performance of metallic micropillars , and energetics found in rutile grain boundaries require accurate detection and identification of surface features. Thus, there is a need for a characterization method that can effectively distinguish both surface and bulk features while being applicable to arbitrary atomic structures.…”