Investigating the synergistic initiating effect on promoting methane hydrate formation via mixed graphene and sodium cholate.

[Display omitted] • Graphene and sodium cholate synergistically accelerate the rapid formation of methane hydrate. • This synergistic acceleration is achieved by increasing partial hydrogen-bonded intermediate water induced by graphene. • Mixed graphene and sodium cholate shows impressive recycling stability for enhancing methane hydrate formation. Gas hydrate is viewed as a promising form to store and transport methane, while the sluggish formation kinetics limits its large-scale utilization. Recently, many nanomaterials have been reported to accelerate the formation of methane hydrate, but their performance is difficult to satisfy the practical application. Additionally, the promoting mechanism of the nanomaterials is yet to be figured out. Here we studied the effect of graphene and sodium cholate on methane hydrate formation. Graphene and sodium cholate show a synergistic effect on methane hydrate formation, corresponding to the induction time halved in the mixture of them than sodium cholate solution. This acceleration was achieved by the increase of intermediate water (IW) induced by the added graphene. IW has the potential to accelerate the nucleation of methane hydrate based on its partial hydrogen-bonded structure. Meanwhile, the mixture of graphene and sodium cholate express excellent recycling stability during the repeated methane hydrate formation − dissociation. The insight of this study can apply to develop high-efficiency kinetic additives for methane hydrate. [ABSTRACT FROM AUTHOR]