Developing Interface Force Fields for Water and Oxygen on Pt, and Pt3Ni, Pt3Co Alloy Surfaces for Proton-Exchange Membrane Fuel Cell (PEMFC) Applications

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–H2O, the best IFF yields a mean absolute error (MAE) of 0.32 eV for adsorption energy and 0.12 eV/Å2 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 Pt3Ni–H2O and Pt3Co–H2O. For Pt/Pt3Ni/Pt3Co–O2, energy MAEs are 0.30–0.68 eV and force MAEs are 0.42–0.85 eV/Å2; errors are larger for force components parallel to the surface, while normal components remain well captured, reflecting the challenges of describing O2 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.

界面力场（Interface Force Fields，IFFs）对于质子交换膜燃料电池（Proton Exchange Membrane Fuel Cell，PEMFC）界面的原子级建模至关重要。我们以密度泛函理论（Density Functional Theory，DFT）的吸附能与吸附力为基准，对10种优化算法与4种力场形式开展了基准测试，并提出了一套用于筛选算法-力场组合的框架。在铂-水（Pt-H₂O）界面体系中，最优界面力场的吸附能平均绝对误差（Mean Absolute Error，MAE）为0.32 eV，吸附力平均绝对误差为0.12 eV/Ų；相较于COMB3、ReaxFF与LJ混合势，其吸附能误差降低了70%~90%，吸附力误差降低了44%~48%。在Pt₃Ni-H₂O与Pt₃Co-H₂O界面体系中也可观察到类似的性能提升。在Pt/Pt₃Ni/Pt₃Co-氧气（O₂）界面体系中，吸附能的平均绝对误差为0.30~0.68 eV，吸附力的平均绝对误差为0.42~0.85 eV/Ų；平行于表面的力分量误差较大，而垂直于表面的法向力分量仍能被较好地拟合，这反映了利用经典力场描述(111)晶面金属表面的氧气解离过程所面临的挑战。该框架可实现数据高效的界面力场开发，并为质子交换膜燃料电池界面模拟中的力场形式与优化算法选择提供指导。