Work

Structure-dependent microkinetic modeling of the CO2 desorption with surface diffusion

Year: 2025

Type: article

Abstract: The interaction of CO2 with Ni catalysts is important for many industrial processes like methanation, which is known to be structure sensitive. Consequently, structure-dependent multiscale modeling is required to accurately capture the interaction of CO2 with the various Ni facets and to provide accurate atomistic insights. While mean-field multiscale models can be constructed that account for multiple active facets, almost all of these studies neglect the diffusion of adsorbates between the facets. In this study, we close the gap by extending the open-source Cantera toolkit with capabilities for surface diffusion in mean-field microkinetic models, making it the first widely adopted software tool that includes these features. We developed a thermodynamically consistent microkinetic model for a Ni nanoparticle consisting of Ni(111), Ni(100), Ni(211), and Ni(110) using data from DFT calculations and single-crystal experiments to unravel the interaction of CO2 with these facets through the simulation of temperature-programmed desorption profiles. Including surface diffusion and coverage effects into the mean-field microkinetic model leads to a significantly improved agreement between experiments from a Ni/SiO2 catalyst and the simulations. Using a rigorous correlated uncertainty quantification of all structural and energetic parameters, we found a detailed chemical model within the uncertainty space that is in excellent agreement with the recorded CO2 desorption profile. This model highlights that Ni(110), which contributes only to a small extent to the overall Ni surface area, dominates the desorption pattern and that surface diffusion reactions play a crucial role. The implemented surface diffusion into Cantera is generic and can be applied to other (mixed) metal nanoparticles and metal/metal oxide interfaces, providing a step towards closing the material gap.

Source: Journal of Catalysis

DOI: 10.1016/j.jcat.2025.116407

Authors: Bjarne Kreitz, Gandhali Kogekar, Raffaele Cheula, C. Franklin Goldsmith

Institutions: Georgia Institute of Technology, Brown University, Aarhus University

Language: English

Topic: Catalysts for Methane Reforming

Subfield: Catalysis

Field: Chemical Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,250