The two-dimensional (2D) honeycomb graphene lattices were demonstrated to be promising hydrogen separation membranes. To effectively operate as hydrogen separation membranes, porous defects and enlargement of pores in these materials must be created. The defect-free 2D stanene (Sn), which is realized in experiment, possesses densely packed intrinsic pores as large as 4.66 angstrom. This work analysed honeycomb 2D Sn-based membranes for hydrogen purification using density functional theory calculations, and found that a fluorinated 2D Sn membrane exhibits excellent hydrogen purification. This purification performance was then tuned for better balanced permeability and selectivity by applying a moderate strain to the membrane. The defect-free fluorinated 2D Sn membrane was identified as suitable for hydrogen purification. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.