Abstract
For gas separation through laminar-structured graphene oxide (GO) membranes, precise nanostructure manipulation is of critical significance for the acquirement of high performance. In this study, facile engineering of GO membranes is realized by combining spraying and solvent evaporation-induced assembly technique. Disordered-to-ordered and porous-to-compact GO membrane structures can be finely and conveniently manipulated via controlling the spraying times and evaporation rate during GO assembly. The as-fabricated GO membranes possess the optimal gas separation performance with H-2/CO2 selectivity of 20.9 and H-2 permeance of 2.7 x 10(-8) mol Pa-1 m(-2) s(-1), which exceeds the upper bound of polymeric membranes. A probable transport mechanism for different gas molecules is applied to clarify the relationships between membrane structure and gas permeation. This study may explore an efficient and facile approach to fabricate defect-free GO membranes with high controllability and practicability. (C) 2016 Elsevier B.V. All rights reserved.