Iridium based materials are one of the most active electrocatalysts used for the oxygen evolution reaction (OER) in polymer electrolyte membrane (PEM) water electrolysers. To increase the utilization, the iridium electrocatalyst is typically dispersed on a high-surface area support material. This results in less iridium being required and consequently reduced catalyst cost. In this work, six metal carbides and oxides were characterized and evaluated as supports for iridium electrocatalyst. The supports studied included: tantalum carbide (TaC), niobium carbide (NbC), titanium carbide (TiC), tungsten carbide (WC), niobium oxide (NbO2), and antimony-doped tin oxide (Sb2O5-SnO2). (C) 2017 Elsevier Ltd. All rights reserved.