Fermi-Based Kinetic Model for the Sabatier Reaction: Sabatier Principle and Beyond It

The CO₂ methanation reaction (also known as the Sabatier reaction) is an important route to convert waste carbon into greater value. In this study, kinetic modeling of the Sabatier reaction proceeding via the CO route has been presented by considering weak and strong chemisorption concepts rooted in electronic theory. Based on the single-route mechanism of the Sabatier reaction, the dependence of the reaction rate on the position of the catalyst Fermi level with respect to the antibonding states of the reagent (CO₂) and the product (CH₄) is demonstrated with the classic Sabatier volcano shape. The model was applied to explain experimental results of reaction rates for Ni- and Ru-based catalytic systems and to understand the origin of the enhancement of turnover frequencies established for dynamic catalysis.