Cobalt-based Fischer–Tropsch synthesis (FTS) catalysts are an integral part of the gas-to-liquid (GTL) process. Due to the cost of both cobalt and noble metals, which are often used as promoters, an extended catalyst life is required to make the process economically feasible. Fundamental understanding of the deactivation mechanisms at play during FTS is key to extending catalyst lifetime. Current insights in the deactivation process point out that carbon deposition and surface reconstruction are two important deactivation mechanisms. In this study, we aim at building a mesoscale ReaxFF-based model to describe such processes.
In previous research projects, a vast dataset of atomic structures was developed using density functional theory calculations. From such a dataset, it is possible to generate a reactive force field (ReaxFF) that describes the multi-body interactions between the atoms. Such force fields descriptions are typically 103-105 times faster to evaluate than the DFT calculations, which makes performing larger scale simulations using such force fields computationally feasible.
In this project, you will further develop a cobalt-carbide force field using the ParAMS training suite. Using this force fields, you will perform larger scale molecular dynamics and Grand-Canonical Monte-Carlo simulations to model a cobalt-carbide lattice and particle and investigate which deactivation processes occur as function fo the carbon potential in the system.
The research questions questions pertaining to this study are:
Movie 1: Conceptual idea how carbon deposition on a cobalt lattice can result in the formation of highly active sites towards CO dissociation via surface reconstruction. In contrast to this conceptual promoting role of carbon, in this study we will focus on deactivating roles of carbon.