Polysulfone (PSf) membrane shows acceptable gas separation performance, but its application is limited by the "trade-off" between selectivity and permeability. In this study, PSf mixed matrix membranes (MMMs) incorporated with palladium (Pd) nanoparticles in the inversed microemulsion were proposed for hydrogen (H-2) separation. Pd nanoparticles can be kinetically stabilized and dispersed using electrostatic and/or steric forces of a stabilizer which is typically introduced during the formation of Pd nanoparticles in the inversed microemulsion. Pd nanoparticles were synthesized by loading (PdCl2) into the polymeric matrix, polyethylene glycol (PEG) which acts as reducing agent and stabilizer. The dry-wet phase inversion method was applied for the preparation of asymmetric PSf MMMs. The effects of Pd (0-4 wt%) on the membrane characteristics and separation performance were studied. Experimental findings verified that the MMMs are able to achieved a high H-2/N-2 selectivity of 21.69 and a satisfactory H-2 permeance of 46.24 GPU due to the changes in membrane structure from fully developed finger-like structure to closed cell structure besides the growth of dense layer. However, the selectivity of H-2/CO2 decreased due to the addition of PEG. (c) 2014 Elsevier B.V. All rights reserved.