NH4HCO3, (NH4)(2)SO4 and (NH4)(2)C2O4 were used as pore-formers to prepare MEAs of proton exchange membrane fuel cells (PEMFC). The addition of NH4HCO3 presented the. best performance of the MEA. ESEM analysis showed that the addition of NH4HCO3 made the dispersion of the catalyst on the surface of the MEA more uniform, and made the surface more porous, leading to low resistance for gas diffusion. The addition of NH4HCO3 reduced the Pt loading in MEA from 0.4 to 0.2 mg cm(-2) and kept the performance of MEA to be unchanged, leading to the cost reduction of the PEMFC. The ratio of the Pt loading and NH4HCO3 was optimized to be the proper value of 1:2, which presented the maximum power density of 0.332 W cm(-2). Addition of NH4HCO3 is an effective way to improve the performance of MEAs, reducing the cost of PEMFC. (c) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.