Novel vermiculite/tannic acid composite aerogels with outstanding CO2 storage via enhanced gas hydrate formation

Gas hydrate-based CO2 storage, using only water cages, provides an environmentally friendly and energy-efficient solution to reduce greenhouse gas emissions. However, the sluggish formation kinetics of gas hydrate is hindered by the limited reaction interfaces, thereby impeding the practical utilization of hydrate-based greenhouse gas storage. Herein, we reported a novel strategy to fabricate natural vermiculite and tannic acid composite aerogels as the effective substrates for boosting CO2 hydrate formation. The results show that the formation kinetics of CO2 hydrate in the aerogels exhibits composition dependence and an outstanding CO2 storage capacity of 130.1 v/v (corresponding to 0.114 mol CO2/mol water). Inverse gas chromatography was used to analyze the surface energy and its components of the aerogels. Raman spectra and nuclear magnetic resonance were used to unravel the water molecule assembly and states. The CO2 uptake capacity can be further improved by compressing the aerogel to 75 % of the original volume, showing an impressive storage capacity of 146.8 v/v. The as-made aerogels demonstrated outstanding cycle stability and short induction time for CO2 hydrate formation. The results of this study pave the way for designing effective CO2 hydrate promoters and facilitating promising CO2 capture and storage technologies via gas hydrate.