The Surprising Role of Urea in Promoting CO₂ Hydrate Formation: Enhanced Molecular Diffusivity via Weakening of the Hydrogen-Bond Network.

ABSTRACT: Urea is known to act as a kinetic promoter for CO₂ hydrate formation by reducing the nucleation induction time. Recent molecular simulation studies suggest that urea facilitates CO₂ hydrate growth by lowering the mass transfer resistance of CO₂ in water, as evidenced by increased diffusivity of both CO₂ and water. However, the enhancement of water diffusivity is counterintuitive, given urea's relatively large size, strong affinity for water, and its tendency to increase the fraction of hydrate-like water structures─conditions typically associated with reduced mobility. To resolve this apparent contradiction, we employ molecular dynamics simulations to examine how urea modifies the hydrogen-bonding network of water, considering both structural and

SUBMITTER: Hsu JW 

PROVIDER: S-EPMC12516713 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature