(391a) Automatically Generated Microkinetic Model Examines Selective NOx Reduction over Pt(111)

Building up an understanding of how 3-way catalytic converters oxidize hydrocarbons and carbon monoxide, while simultaneously reducing NOx is important to the design of future catalysts. Previously, Kreitz et al. (DOI:10.1021/acscatal.2c03378) generated a microkinetic model for the oxidation of carbon monoxide and small hydrocarbons over Pt/Al₂O₃. While these oxidative reactions are taking place, selective reduction of nitric oxide over Pt/Al₂O₃ also occurs. In order to better understand the ability of Pt to selectively reduce NOx, a detailed microkinetic model is generated using the workflow of the Reaction Mechanism Generator (RMG).
RMG is an open source software which uses uses a cheminformatics framework in combination with DFT data, generic reaction templates, and estimation routines to automatically generate microkinetic models. Prior to now, RMG was unable to consider reactions with nitrogenous adsorbates. Here we expand the databases, reaction templates, and estimation routines within RMG so that it can explore nitrogen chemistry. With these new features in place, RMG was able to converge on a microkinetic model for the selective reduction of NOx on Pt(111).Following this, an ensemble of mechanisms within the correlated uncertainty space of the DFT data were then generated as proposed by Kreitz et al. (DOI:10.1002/anie.202306514). From this ensemble of possible mechanisms, a unique microkinetic model can be identified in good agreement with the data. Degree of rate control analysis was performed on the model to evaluate rate controlling steps and intermediates. With these added features, RMG is now equipped to consider other reactions where nitrogen chemistry is important as well.