CatMAP: A Software Package for Descriptor-Based Microkinetic Mapping of Catalytic Trends

Abstract

Descriptor-based analysis is a powerful tool for understanding the trends across various catalysts. In general, the rate of a reaction over a given catalyst is a function of many parameters-reaction energies, activation barriers, thermodynamic conditions, etc. The high dimensionality of this problem makes it very difficult and expensive to solve completely, and even a full solution would not give much insight into the rational design of new catalysts. The descriptor-based approach seeks to determine a few ''descriptors'' upon which the other parameters are dependent. By doing this it is possible to reduce the dimensionality of the problem-preferably to 1 or 2 descriptors-thus greatly reducing computational efforts and simultaneously increasing the understanding of trends in catalysis. The ''CatMAP'' Python module seeks to standardize and automate many of the mathematical routines necessary to move from ''descriptor space'' to reaction rates for heterogeneous (electro) catalysts. The module is designed to be both flexible and powerful, and is available for free online. A ''reaction model'' can be fully defined by a configuration file, thus no new programming is necessary to change the complexity or assumptions of a model. Furthermore, various steps in the process of moving from descriptors to reaction rates have been abstracted into separate Python classes, making it easy to change the methods used or add new functionality. This work discusses the structure of the code and presents the underlying algorithms and mathematical expressions both generally and via an example for the CO oxidation reaction. Graphical Abstract

Mechanistic Insights into Ethylene Transformations on Ir(111) by Density Functional Calculations and Microkinetic Modeling

“…The reaction rate was obtained from the CatMAP code . We plotted the volcano plot of catalyst activity for ethane production from ethylene hydrogenation over different metal surfaces as a function of H* and C 2 H 4 * adsorption energies by providing the adsorption energies, reaction energies and barriers on the Ir(111), Pd(111), Pt(111), and Rh(111) surfaces.…”

Degree of rate control approach to computational catalyst screening

“…All rate volcanoes generated by the NB method were constructed using the Catalysis Microkinetic Analysis Package (CatMAP) module for Python [36,37], which is a web-accessible program that essentially follows the procedure described above for the NB method, described in more detail in [5,16]. CatMAP allows for the calculation of catalytic rates, as well as the degree of rate control, given the standard-state free energies of all the adsorbed intermediates and transition states.…”

“…It also generates the linear scaling relationships for each adsorbate and transition state using the DFT energies for a select set of materials [37].…”

Theory and applications of surface micro‐kinetics in the rational design of catalysts using density functional theory calculations

“…Similarly, the scaling relation indicates that there are linear relationships between adsorption energies of similar adsorbates, and for a complicated system, the energies of all intermediates can usually be related to one or two key intermediates . Therefore, with the BEP and scaling relations, the reaction rate can finally be expressed as a function of the adsorption energy of one or two key intermediates by solving the micro‐kinetics of the catalytic system . As shown in Figure , when the adsorption strength is weak, the whole reaction is limited by the activation of the reactant; if the binding is strong, the desorption of the product would be limited.…”