In this work, three types of carbon - Vulcan XC-72R, long vapor-grown carbon nanotubes (LVGCNTs, 7 mu m long, 100 nm in diameter), and short vapor-grown carbon nanotube (SVGCNT, 3 mu m long, 100 nm in diameter) - were investigated as materials composing a micro-porous layer (MPL). Vulcan XC-72R was sprayed on carbon paper to form an MPL with various carbon loadings from 0.5 to 3.0 mg cm(-2), and formed a custom-made gas diffusion layer (GDL) which was subjected to further study. Physical property tests such as through-plane resistance, gas permeability and contact angle were measured. Based on the results of these tests, the best carbon loading for the Vulcan XC-72R was applied to LVGCNT and SVGCNT for a fuel cell performance test. The physical properties and fuel cell performance of the custom-made GDL were investigated and compared with those of the commercially available GDL SGL 10BC. (c) 2012 Elsevier Ltd. All rights reserved.