(558v) Calculation of Catalytic Activity for Alloy Nanoparticles with Experimentally Relevant Sizes By Explicitly Predicting Adsorbate Binding Energy

We present the use of ab-initio calculations and the cluster expansion method to calculate the catalytic activity of alloy nanoparticles with experimentally relevant sizes (5 nm ‒ 10 nm) by explicitly predicting the atomic-scale structures and adsorbates binding energies on the surface. We demonstrate our approach using Pt–Ni nanoparticles as catalysts for the oxygen reduction reaction (ORR). This is accomplished by building a quaternary Pt‒Ni‒OH-Vacancy cluster expansion model to explicitly predict *OH binding energies, which are correlated to ORR activity using volcano plot. This model enables us to accurately investigate the catalytic activity of various surface sites with different coordination numbers and local atomic environments. Using this model, we evaluate how the different parameters affect the ORR activity of Pt–Ni nanoparticles: size (2 nm ‒ 10 nm), Pt composition (50% ‒ 100%), and shape. To determine the atomic structures of nanoparticles after experimental activation, we simulate the Ni dissolution process using a kinetic Monte Carlo (KMC) model. We also demonstrate the time evolution of ORR activity for Pt‒Ni nanoparticles during the KMC process. This approach provides theoretical insights on how to tune the structures of alloy nanoparticles to optimize catalytic activity.