Pt nanoparticles with about 2 nm are successfully deposited onto similar to 50 nm commercial TiO2 and various Nafion/xPt-TiO2/(1-x)Graphene oxide composite membranes are prepared. Water uptake of composite membrane is enhanced with GO content by maximum 15.3% due to hydrophilic GO compared to casting Nafion. Ion exchange capacity and proton conductivity are also enhanced with GO content but too much GO incorporation seems to reduce them probably due to the blocking effect by 2-dimensional GO sheets. Hydrophilic TiO2 alone does not seem to exhibit sufficient water retention ability to exert excellent cell performance. The results clearly show that the cell performance under low humidifying condition including zero humidity is significantly affected by retention ability of water formed from Pt sites. Thermogravimetric analysis shows that free water retained by membrane could be increased by 32% with the addition of TiO2 and 45% further with additional GO compared with that of casting Nafion, respectively. The cell performance is significantly enhanced by sinergistic effect upon addition of appropriate amount of Pt-TiO2 and GO to Nafion: that is, at 0.6 V, 1.0 A/cm(2) and 0.54 A/cm(2) for Nafion/0.8Pt-TiO2/0.2GO, and 0.42 A/cm(2) and 0.0(2) A/cm(2) for casting Nafion under 100% RH and 0% RH. (C) 2016 Elsevier B.V. All rights reserved.