Microkinetic Modeling of the Transient CO₂ Methanation with DFT‐Based Uncertainties in a Berty Reactor

Abstract

Abstract The transient operation of methanation reactors can become desirable when coupled with fluctuating renewable energies in Power‐to‐Gas scenarios, which requires suitable kinetic approaches that can describe the transient catalytic phenomena. A combined experimental and theoretical investigation of the transient CO 2 methanation is conducted using concentration forcing to derive a suitable microkinetic model. Methanation experiments are performed with a Ni/SiO 2 catalyst in a Berty‐type reactor at industrially relevant conditions. The microkinetics are based on previous work and were automatically constructed for the Ni(111) facet using the Reaction Mechanism Generator. A feasible set of energetic parameters of the microkinetic models was identified in a theory‐constrained optimization procedure within the DFT uncertainty space that can accurately reproduce the experimental results on a first‐principles basis. The microkinetic model unravels that the formation of H 2 O* and CH 3 * control the activity and selectivity of Ni(111) under the investigated conditions.