Efficient parametrization and deployment of constant potential models based on automatic differentiation: application...

In this study, we present a differentiable charge equilibration (Q_eq) approach integrated into the JAX-based Differentiable Molecular Force Field (DMFF) package. This innovation enables highly efficient automatic differentiation of various properties with respect to atomic Q_eq parameters, facilitating the construction of a versatile force field optimization and simulation framework for electrochemical catalytic interfaces. Using M-C-N catalysts as a model system, we investigate CO₂ adsorption in aqueous electrolytes. Our results reveal that the surface charge of M-C-N materials governs the orientation and density distributions of interfacial water molecules, giving rise to distinct hydration layers. Notably, a negatively charged electrode is optimal for CO₂ adsorption at the doping center as it balances electrostatic attraction and competitive adsorption of H₂O. These observations provide critical insights for the rational design of CO₂ reduction catalysts and demonstrate the importance of simulation with explicit solvent for electrochemical interfaces.