The clathrate hydrate memory effect is a fascinating phenomenon with potential applications in carbon capture

utilization and storage (CCUS)

gas separation

and gas storage as it can accelerate the secondary formation of clathrate hydrate. However

the underlying mechanism of this effect remains unclear. To gain a better understanding of the mechanism

we conducted molecular dynamic simulations to simulate the initial formation and reformation processes of methane hydrate. In this work

we showed the evolution process of hydrate residual structures into hydrate cages. The simulation results indicate that the residual structures are closely related to the existence of hydrate memory effect

and the higher the contribution of hydrate dissociated water to the hydrate nucleation process

the faster the hydrate nucleation. After hydrate dissociation

the locally ordered structures still exist after hydrate dissociation and can promote the formation of cluster structures

thus accelerating hydrate nucleation. Additionally

the nucleation process of hydrate and the formation process of clusters are inseparable. The size of clusters composed of cup-cage structures is critical for hydrate nucleation. The residence time at high temperature after hydrate decomposition will affect the strength of the hydrate memory effect. Our simulation results provide microscopic insights into the occurrence of the hydrate memory effect and shed light on the hydrate reformation process at the molecular scale.