AVS 66th International Symposium & Exhibition
    Fundamental Discoveries in Heterogeneous Catalysis Focus Topic Monday Sessions
       Session HC+SS-MoM

Invited Paper HC+SS-MoM3
Towards a Chemically Accurate Description of Reactions of Molecules with Transition Metal Surfaces

Monday, October 21, 2019, 9:00 am, Room A212

Session: Utilization of Theoretical Models, Machine Learning, and Artificial Intelligence for Heterogeneously-Catalyzed Reactions
Presenter: Geert-Jan Kroes, Leiden University, Netherlands
Correspondent: Click to Email
Heterogeneously catalyzed processes consist of several elementary reactions. Accurately calculating their rates requires the availability of accurate barriers for the rate controlling steps. Unfortunately, currently no first principles methods can be relied upon to deliver the required accuracy. To solve this problem, in 2009 we came up with a novel implementation of the specific reaction parameter approach to density functional theory (SRP-DFT). This allowed us to reproduce experiments for H2 reacting on copper surfaces, and to determine barrier heights for H2-Cu systems, with chemical accuracy. The original procedure used was not extendable to reactions of molecules heavier than H2 with surfaces, because the metal surface was treated as static. This problem has been solved by combining SRP-DFT with Ab Initio Molecular Dynamics (AIMD). This method was applied to the dissociative chemisorption of methane on a Ni surface, a rate-limiting step in the steam reforming reaction. We were able to reproduce experiments on CHD3 + Ni(111) with chemical accuracy, and have predicted a value of the reaction barrier height that we claim to be chemically accurate. We have new results for CHD3 + Pt(111) that are even better, and which show that the SRP density functional for methane interacting with Ni(111) is transferable to methane interacting with another group X metal surface, i.e., Pt(111). Even more interestingly for applications to catalysis, the SRP functional derived for methane reacting with Ni(111) also gives a very accurate description of molecular beam sticking experiments on CHD3 + Pt(211). Finally, thanks to a collaboration with Jörg Behler (University of Göttingen) we are now able to develop potential energy surfaces also depending on the degrees of freedom associated with the surface phonons, for polyatomic molecules interacting with metals. This has enabled us to compute statistically accurate reaction probabilities for highly activated reactions not open to investigation with AIMD, for which reaction probabilities are less than 0.01.