A comprehensive review on the incremental synthesis characteristics and regulation mechanism of natural gas hydrates enhanced by porous skeleton structure: challenges, perspectives and future directions

Natural gas has been widely regarded as a clean transitional fuel owing to its relatively low carbon intensity, high combustion efficiency and stable energy output. Hydrate-based natural gas storage and transportation has therefore attracted increasing attention as an emerging solid-state energy storage technology. However, the practical deployment remains limited by long hydrate induction times, slow formation kinetics and insufficient gas storage density. Porous skeleton systems, with tunable confinement environments and interfacial regulation capabilities, offer a promising route to intensify natural gas hydrate formation and improve storage performance. This review comprehensively summarizes the confinement effects and interfacial regulation mechanisms of porous skeleton materials during natural gas hydrate formation, with particular emphasis on their roles in promoting hydrate synthesis. The roles of key structural parameters, including pore size, specific surface area, pore volume, surface chemistry, pore topology and network connectivity, in governing hydrate nucleation, growth kinetics, and gas-storage capacity are discussed in detail. The underlying microscopic mechanisms are further examined, including gas enrichment, interfacial water restructuring, heterogeneous nucleation, mass and heat transfer, and pore-scale hydrate growth. On this basis, the kinetic laws and regulatory mechanisms of porous skeleton-enhanced hydrate formation are clarified. Finally, the deficiencies and future development directions for hydrate-based natural gas storage and transportation technology were identified. Future research should focus on artificial intelligence-assisted material design, molecular- and interfacial-scale mechanistic studies, and multiphysics coupling models. These advances will provide a scientific foundation for the rational design of porous skeleton systems and the development of hydrate-based natural gas storage technology.