Optimizing CO₂ Hydrate Formation for Integrated Capture, Transport, and Sequestration: Key Influencing Factors and Enhancement Strategies

Hydrate-based CO₂ capture, transport, and sequestration represent an emerging strategy for mitigating carbon emissions, leveraging the high gas storage capacity and the stability of CO₂ hydrate. This integrated approach relies fundamentally on the controlled formation of hydrates, a process governed by thermodynamic, kinetic, and environmental factors. This review comprehensively analyzes key factors influencing CO₂ hydrate formation and proposes enhancement strategies applicable across the full carbon management chain. Thermodynamic promoters optimize phase equilibrium conditions, while kinetic promoters improve heat and mass transfer efficiency. Various kinetic promoters contribute uniquely across the four stages of hydrate formation, including dissolution, nucleation, growth, and equilibrium. For instance, surfactants shorten the induction time by reducing interfacial tension, nanoparticles and porous media enhance gas storage capacity by providing nucleation sites, and phase change materials improve heat and mass transfer. The complex interplay of salinity, ion concentration, and pH in marine environments collectively governs CO₂ hydrate formation efficiency and long-term sequestration stability. A systematic comparison of commonly used thermodynamic and kinetic promoters reveals that they face challenges in efficiency, environmental impact, cost, and engineering adaptability. Based on a systematic assessment of recent studies, this review recommends that future work prioritize the development of environmentally compatible composite promoters with optimized concentrations, efficacy, and cost. Furthermore, establishing a multidimensional evaluation framework will be essential to transition hydrate-based CO₂ management from laboratory research to real-world engineering applications.