Confinement-Modulated Proton-Transfer Kinetics in Graphene and Graphene-Oxide Nanochannels: A Markovian Statistical...

Ångström-scale confinement profoundly alters the structure, hydrogen-bond topology, and dielectric response of water, giving rise to anomalous proton transport and reactivity in two-dimensional nanochannels. Despite recent experimental reports of giant in-plane dielectric constants and superionic-like proton conduction, the microscopic kinetics governing proton-transfer reactions under such extreme confinement remain poorly understood. Here, we combine reactive molecular dynamics (ReaxFF MD), ab initio molecular dynamics (AIMD) simulations, and a continuous-time Markovian statistical framework to quantitatively resolve hydroxide-water proton-transfer kinetics in pristine and functionalized graphene nanochannels. By analyzing the waiting-time statistics of individual proton-transfer events, we demonstrate that proton hopping follows exponential waiting-time distributions, consistent with a memoryless Markov process characterized by a single, well-defined rate constant on picosecond time scales. Nanoconfinement accelerates proton transfer by factors of 2-4 relative to bulk water, corresponding to an effective activation-energy-conversion reduction of approximately 6-10 kJ mol^-1. Structural defects, surface charge, and oxygen functional groups in graphene oxide further amplify this effect by generating strong interfacial electric fields and catalytic hotspots that promote proton hopping. These microscopic kinetic trends provide a quantitative mechanistic basis for the enhanced dielectric response and fast in-plane proton transport observed experimentally in Ångström-scale channels. More broadly, our results establish a general statistical framework for linking atomistic proton-transfer dynamics to emergent transport phenomena, offering new insights into confinement-induced reactivity, dielectric anomalies, and ion transport in low-dimensional aqueous systems.