The oxidant supply coupled with the cooling task in open-cathode proton exchange membrane fuel cells (PEMFCs) creates a simple system configuration. Based on a simulated condition which was previously established for evaluating cell performance of different membrane electrode assemblies, this work has conducted performance optimization by altering electrocatalysts, thickness of micro-porous layer (MPL) and membranes. The thickness of the catalyst layers was around similar to 35 mu m with 20 wt% Pt/C, and reduced to only 12 mu m with 60 wt% Pt/C. Although a thick catalyst layer resulted in a stable performance at various air stiochiometric ratios, especially under high temperatures where cell performance decreased due to a low Pt utilization and poor mass transport of proton and reactants in the cathode. The cathode with 2 mg cm(-2) carbon loading in the MPL gave the best performance and the cell voltage varied between 0.71 and 0.62 V at 800 mA cm(-2) in the temperature range from 50 degrees C to 60 degrees C. Finally, different membranes were investigated, and a thin composite Nafion/PTFE membrane around 17 gm showed better performance comparing to Nafion 211, which can be attributed to a good water retention capacity owing to easy crossover of hydrogen and water through the membrane. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.