Unraveling nucleation pathway in methane clathrate formation

• DOI: 10.1073/pnas.2011755117
• Publication Date: 2020-09-22T00:40:48Z
• Authors: Liwen Li; Jie Zhong; Youguo Yan; Jun Zhang; Jiafang Xu; Joseph S. Francisco; Xiao Cheng Zeng
• Keywords: 13. Climate action; 01 natural sciences; 0104 chemical sciences

Significance Understanding the clathrate formation mechanism has important implications on natural gas exploitation, storage, and transportation. A key toward clathrate formation is the hydrate nucleation, which involves complex interplay between water and guest molecules at nanoscale and multiple kinetic stages. Herein, by tracing the kinetic evolution of multiple ternary water-ring aggregations based on trajectories of large-scale molecular dynamics simulations, we identified a generic nucleation pathway to clathrate formation. This observed nucleation pathway is driven by numerous compression/shedding processes among the methane hydration layers, and it can explain the widely accepted “blob” model of clathrate nucleation. The molecular insight into the nucleation pathway allows us to quantitatively assess the nucleation timescales as well as the critical nucleus sizes in the clathrate formation.