▎ 摘　　要

Graphene oxide (GO) membranes have generated a great deal of interest in the development of high performance membranes for gas separation. However, metastable GO undergoes structural transformation with temperature and time, which would cast its impact on the permeation properties of the membranes. Herein, we report a significant enhancement (nearly 20 times) in the gas permeability of annealed GO membranes compared to the as-prepared ones owing to the creation of easy permeation pathways for gas molecules. We also demonstrated that these membranes perform very well for H-2/CO2 separation compared to the previously reported inorganic membranes and are well above the upper bounds of polymeric membranes.