Modeling solid-liquid interface reactions with next generation extended Lagrangian quantum-based molecular dynamics

TL;DR

This paper applies extended Lagrangian Born-Oppenheimer quantum molecular dynamics to model electron transfer reactions at solid-liquid interfaces, demonstrating its effectiveness in simulating catalytic processes relevant to fuel cells.

Contribution

The study introduces a novel application of XL-BOMD to simulate electron transfer at solid-liquid interfaces, reducing computational cost by requiring only one self-consistent charge relaxation.

Findings

Successfully modeled electron transfer and O2 dissociation at the interface.

Demonstrated stability and efficiency of XL-BOMD in complex electrochemical systems.

Captured atomic-scale quantum effects critical for catalytic activity.

Abstract

We demonstrate the applicability of extended Lagrangian Born-Oppenheimer quantum-based molecular dynamics (XL-BOMD) to model electron transfer reactions occurring on solid-liquid interfaces. Specifically, we consider the reduction of O$_2$ as catalyzed at the interface of an N-doped graphene sheet and H$_2$O at fuel cell cathodes. This system is a good testbed for next-generation computational chemistry methods since the electrochemical functionalities strongly depend on atomic-scale quantum mechanics. As opposed to prior iterations of first principles molecular dynamics, XL-BOMD only requires a full self-consistent-charge relaxation during the initial time step. The electronic ground state and total energy are stabilized thereafter through nuclear and electronic equations of motion assisted by an inner-product kernel updated with low-rank approximations. A species charge analysis reveals that the kernel-based XL-BOMD simulation can capture an electron transfer between the PGM-free catalyst and a solvated O$_2$ molecule mediated by H$_2$O, which results in the molecular dissociation of O$_2$.