Amino Acid Promotes Ultrarapid Clathrate Formation from Liquid CO2 for Offshore Carbon Dioxide Sequestration

Achieving global net-zero emissions necessitates advancements in sustainable CO2 sequestration technologies. CO2 sequestration in subsea sediments in the form of clathrates presents a promising option due to inherent reaction conditions, high CO2 storage capacity, and superior stability. However, the sluggish CO2 hydrate formation kinetics significantly constrains its field-scale application, particularly in the process of CO2 hydrate cap formation to prevent the CO2 leakage. Herein, we propose a biomolecular strategy by using the low-dose hydrophobic amino acid l-methionine to address this challenge. Combining morphological imaging and in situ Raman spectroscopy, l-methionine was found to disrupt the rigid CO2 hydrate films and induces self-organized liquid CO2 transport channels, significantly reducing CO2 mass transfer resistance. Molecular-level analysis further reveals that the hydrophobic group of l-methionine leads to a 70% decrease in the energy barrier of the CO2 diffusion. This biocompatible promoter enables ultrahigh CO2 uptake (120.6 v/v) with a 15-fold enhancement over pure water. Rapid CO2 hydrate formation for hydrate-sediment cementation was further validated using the acquired South China Sea clayey-silty marine sediments. This environmentally benign strategy demonstrates extraordinary CO2 hydrate formation kinetics from liquid CO2 compared to the state-of-the-art promoters, offering a promising and practical solution for long-term offshore CO2 storage to mitigate climate change.