A first principles approach to modeling surface site stabilities on multi-metallic catalysts

The study of multi-metallic alloys and the multitude of surface compositions possible have sparked a tremendous interest in engineering low-cost materials with high activity and selectivity in heterogeneous catalysis. Multi-metallic systems provide complementary functionalities and an unprecedented tunability when designing catalyst formulations. However, due to their immense structural and compositional complexity, the investigation and identification of an optimal catalyst is a tedious and time-consuming process, both experimentally and theoretically. Therefore, theoretical design principles are highly desirable to accelerate the screening of catalyst structures across the vast compositional space. In this paper, we introduce a simple and general model for predicting the site stability of multi-metallic surfaces and nanoparticles, which is based on physical principles. The model requires only a small set of density functional theory (DFT) calculations of metal atom binding energies on monometallic and dilute alloy surface slabs to optimize the parameters in the simple model. The resulting model allows for the quantification of the stability of any particular atom site in any conceivable chemical environment across a wide range of morphologies, sizes, and arrangements by interpolating the derived parameters from a monometallic to a completely diluted alloyed system. Herein, we demonstrate the robustness of the model across an extensive data set of transition metal alloy surfaces and 147 atom cuboctahedral nanoparticles composed of  IrRhRu and PtPdRu. Our approach yields mean absolute errors of $\approx$ 0.15 eV, 0.20 eV, 0.19 eV, and 0.26 eV, relative to site binding energies calculated using DFT, respectively.