Automatic mechanism generation involving kinetics of surface reactions with bidentate adsorbates

Abstract

The open-source Reaction Mechanism Generator (RMG) has been enhanced with new features to handle multidentate adsorbates. New reaction families have been added based upon ab initio data from 26 reactions involving C_xO_yH_z bidentate adsorbates with two heavy atoms on Pt(111). Additionally, the estimation routines for thermophysical properties were improved and extended towards bidentate species. Non-oxidative dehydrogenation of ethane over Pt(111) is used as a case study to demonstrate the effectiveness of these new features. RMG not only discovered the pathways from prior literature but also uncovered new elementary steps involving abstraction reactions. Various mono- and bimetallic catalysts for this process were screened using linear scaling relations within RMG, where a unique mechanism is generated for each catalyst. These results are consistent with prior literature trends, but they add additional insight into the rate-determining steps across the periodic table. With these additions, RMG can now explore more intricate reaction mechanisms of heterogeneously catalyzed processes for the conversion of larger molecules, which will be particularly important in fuel synthesis.