Volcano Curves for in Silico Prediction of Mono- and Bifunctional Catalysts: Application to Ammonia Decomposition

Computational screening of catalysts with complex microstructures and/or multiple interacting sites is challenging. Here, we evaluate the ammonia decomposition on perfect and patched core-shell bimetallic facets using a hierarchy of kinetic models, namely, scaling relations (SRs)-based mean-field microkinetic models (SR-MKM), and first-principles (FP) and SR-based spatially resolved kinetic Monte Carlo (FP- and SR-KMC) simulations. SR-KMC volcanos possess a double-peak on perfect facets and a single peak on patched bimetallic facets. When lateral interactions of the most abundant surface intermediate are strong, only the KMC method predicts the volcano accurately. Dual site (bifunctional) materials exhibit a considerably different volcano curve from monofunctional materials and thus, multifunctional materials' property prediction requires KMC calculations. Our computational screening highlights the importance of the microstructure of multifunctional catalysts.