Fischer-Tropsch synthesis (FTS) is a key catalytic process for converting synthesis gas (CO + H₂) into hydrocarbons and fuels. Cobalt-based catalysts are widely used in industrial FTS due to their high activity and selectivity toward long-chain hydrocarbons. At the atomic scale, the reaction proceeds through a complex network of elementary surface steps involving adsorbed carbon, hydrogen, CHₓ fragments, and growing hydrocarbon chains. Under realistic reaction conditions, these intermediates can occupy a significant fraction of the surface, leading to crowded environments where adsorbates strongly influence one another.
Most elementary reaction models assume that adsorption energies and activation barriers are independent of surface coverage. In reality, adsorbates interact laterally through steric, electronic, and elastic effects. These interactions can alter adsorption strengths, modify transition-state energies, and change the relative stability of intermediates. As a result, the effective kinetics under working conditions can differ substantially from predictions based on low-coverage data.
Incorporating lateral interactions into kinetic models introduces an additional layer of complexity. Adsorption energies become coverage-dependent, and reaction rates may depend non-linearly on the populations of neighboring species. Such effects can be described using approaches ranging from mean-field interaction terms to lattice-based models or cluster expansions. Understanding how these interactions influence overall activity and product distributions is an active area of research in surface catalysis.
This project therefore connects surface thermodynamics, reaction kinetics, and statistical mechanics. By extending a microkinetic description of Fischer-Tropsch chemistry to include lateral interactions, you will explore how collective surface effects shape catalytic performance beyond the idealized dilute-coverage limit.
A report describing the theoretical framework for lateral interactions and its implementation within a kinetic model. The report should compare results with and without coverage effects, highlighting differences in predicted rates, surface compositions, and product distributions. A critical discussion of the limitations of mean-field interaction models and possible extensions (e.g., lattice Monte Carlo approaches) should also be included.