Antimony doped tin oxide (ATO) was studied as a support material for IrO2 in proton exchange membrane water electrolyser (PEMWE). Adams fusion method was used to prepare the IrO2-ATO catalysts. The physical and electrochemical characterisation of the catalysts were carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder conductivity, cyclic voltammetry (CV) and membrane electrode assembly (MEA) polarisation. The BET surface area and electronic conductivity of the supported catalysts were found to be predominantly arisen from the IrO2. Supported catalyst showed higher active surface area than the pristine IrO2 in CV analysis with 85% H3PO4 as electrolyte. The MEA performance using Nafion (R)-115 membrane at 80 degrees C and atmospheric pressure showed a better performance for IrO2 loading >= 60 wt.% than the pristine IrO2 with a normalised current density of 1625 mA cm(-2) @1.8 V for the 60% IrO2-ATO compared to 1341, mA cm(-2) for the pristine IrO2 under the same condition. The higher performance of the supported catalysts was mainly attributed to better dispersion of active IrO2 on electrochemically inactive ATO support material, forming smaller IrO2 crystallites. A 40 wt.% reduction in the IrO2 was achieved by utilising the support material. Crown Copyright (C) 2014 Published by Elsevier B.V. All rights reserved.