The manipulation of the interfacial evaporation property of graphene porous membranes

Abstract

Graphene membranes of excellent solar absorption and photothermal conversion efficiency have been used in solar-driven water evaporation (SDWE) systems as light-harvesting material. The interfacial evaporation property between graphene membranes and seawater is an important issue to further promote the development of SDWE. In this work, manipulation strategies are presented based on porous structures for tailoring the evaporation performance of graphene membranes. The non-equilibrium molecular dynamic (NEMD) simulation results show that the pore size, pore concentration, and distribution pattern are all key factors in enhancing the evaporation rate. The evaporation performance can achieve the best optimisation when the pore size is 3.1 Å and the pore concentration is the lowest. Moreover, the periodic distribution of porous structures can greatly increase the evaporation rate (about 100 water molecules per nanosecond) due to the improvement of adsorption and desorption balance compared with the random structure. The optimised configuration of the graphene porous used in SDWE systems is proposed, which could increase the evaporation rate to 357.1%. This study could provide some theoretical guidance on graphene membranes for application in both photothermal conversion and solar-driven water purification.