Molecular dynamics insights into water confined in zeolite-templated carbon nanomaterials

Abstract

Water confined in zeolite-templated carbons (ZTCs) exhibits properties fundamentally different from those of bulk liquid, with profound implications for energy storage, separation technologies, and catalysis. Despite the technological importance of water behavior in ZTC nanopores, molecular-level understanding remains limited. This work presents comprehensive molecular dynamics (MD) simulations investigating the structure, dynamics, and hydrogen bonding characteristics of water confined within faujasite-derived ZTC. Classical MD simulations were developed with validated force fields to characterize radial and spatial distribution functions, hydrogen bond networks and lifetimes, cluster size distributions, domain formation, translational and rotational dynamics, and velocity autocorrelation functions. Systematic comparison with bulk liquid water reveals confinement-induced modifications to tetrahedral hydrogen bonding networks, spatial organization into discrete domains, hydrogen bond dynamics, and transport properties. The three-dimensional hierarchical pore topology of ZTC creates unique confinement environments distinct from one-dimensional nanotubes or two-dimensional slit pores. These findings provide molecular-level insights essential for the rational design of ZTC-based materials for electrochemical energy storage, water desalination membranes, proton exchange systems, and aqueous-phase catalysis, thereby advancing fundamental understanding of water confinement in complex carbon nanostructures.