To rationalize the energy requirements and environmental complications of the world, supply of pure hydrogen is the most promising as well best possible approach of such issues. Purified hydrogen gas is the necessity factor for the hydrogen-based economy. Hydrogen perm-selective membrane plays a crucial role for producing a large amount of hydrogen. Palladium is one of the best materials because of its excellent affinity to absorb hydrogen. In present work, our aim to improve selectivity as well permeability of the H-2 gas compare to N-2 and CO2 gases of the block copolymer coated functionalized porous PET membrane. Porous polyethylene terephthalate (PET) membranes having pore size 0.2 mu m, functionalized with a carboxyl group. The supramolecular assembly was prepared from PS (35500)-b- P4VP (4400) and 2-(4- Hydroxyphenylazo) benzoic acid (HABA) in 1, 4-dioxane. Chemically synthesized palladium nanoparticles were deposited on carboxylated block copolymer (BC) coated porous PET membrane. It is an appropriate way to use H-2 sensitive materials with block copolymer coated functionalized membranes to enhance the selectivity of H-2. It has been found that such membranes gain better permeability and selectivity towards H-2 as compared with N-2 and CO2. Increment with the dipping time of these membranes in the palladium nanoparticle solution, permeability as well selectivity of H-2 over N-2, CO2 increases as the more attachment of Palladium nanoparticles. A fine active layer of block copolymer on the carboxyl functionalized PET membrane play a crucial role for hydrogen based gas separation. The magnitude of the permeability of such membranes for different gases shows dependency on the pore size of the upper layer (BC coated) of the membrane in addition to the molecule size of the permeating gas. Block copolymer coating of the membranes established an effective responsibility for the selectivity of H-2 over CO2 gas as well over N-2 gas. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.