Developing Interface Force Fields for Water and Oxygen on Pt, and Pt 3 Ni , Pt 3 Co Alloy Surfaces for Proton-Exchange Membrane Fuel Cell (PEMFC) Applications

High Resolution Image Download MS PowerPoint Slide Interface force fields (IFFs) are crucial for the atomistic modeling of PEMFC interfaces. We benchmark ten optimization algorithms and four force-field forms against DFT adsorption energies and forces and present a framework for selecting the algorithm/force-field combination. At Pt–H 2 O, the best IFF yields a mean absolute error (MAE) of 0.32 eV for adsorption energy and 0.12 eV/Å 2 for forces, cutting energy error by 70–90% and force error by 44–48% compared to COMB3, ReaxFF, and LJ mixing. Similar improvements are observed for Pt 3 Ni–H 2 O and Pt 3 Co–H 2 O. For Pt/Pt 3 Ni/Pt 3 Co–O 2, energy MAEs are 0.30–0.68 eV and force MAEs are 0.42–0.85 eV/Å 2; errors are larger for force components parallel to the surface, while normal components remain well captured, reflecting the challenges of describing O 2 dissociation on (111) metal surfaces using classical force fields. The framework enables data-efficient IFF development and guides the selection of force-field forms and optimization algorithms for PEMFC and interfacial simulations.