Parameterization of ReaxFF Force Field for Pd-Ceria From First Principles DFT Calculations

Recent Density Functional Theory (DFT) studies of Pd/ceria have demonstrated the stability and activity of the Pd-ceria system. However, the computational intensity inherent to quantum-level calculations prevents DFT studies from reaching the necessary length and time scales required to characterize the structural rearrangement and reaction dynamics of the catalyst surface.  For this reason, a Reactive Force Field (ReaxFF) model, parameterized with quantum mechanical data obtained from DFT, that is capable of reaching the required length and time scales will be used to study the dynamic restructuring of the catalyst surface during reaction. DFT calculations are performed to identify the optimal structure and energy of various Pd/O/C/H species. Climbing Image-Nudged Elastic Band (CI-NEB) calculations are used to identify transition states and activation energies. The resultant DFT data is then used to train the ReaxFF force field for use in reactive molecular dynamics (RMD) simulations of the Pd-ceria catalyst.