Proton-Coupled Electron-Transfer Dynamics of Water Oxidation at N-Doped Graphene Oxides

In this contribution, the dynamics of a proton-coupled electron-transfer (PCET) process for nitrogen-doped graphene oxide (NGO) model systems is studied. The real-time electron dynamics of the overall process is calculated in the reduced density-matrix framework of time-dependent configuration interaction (ρ-TDCI) including the nonadiabatic decay channels of thermalization and proton transfer. In a preliminary electronic-structure calculation, the charge-transfer (CT) states are identified and characterized within the energy range of the sunlight spectrum. The states with the most CT character are, however, the darker ones. Computations reveal that these dark PCET-active electronic states can be accessed via excitation of bright, neighboring PCET-inactive states. Depending on the order of magnitude of the thermalization times of states, the thermal population transfer can increase the PCET efficiency for longer-lived intermediate states but can also become competitive with the PCET process itself for very high thermal population transfer rates.