Two differently structured Nb-doped TiO2 support materials, i.e., mesoporous microspheres and nanofibers, were synthesized and used as Pt catalyst supports for the oxygen reduction reaction (ORR), which is a critical research topic for PEM fuel cells. Compared to a commercially available Pt/C catalyst, improved electrochemical ORR stability was observed when using the novel supports in an acidic environment. XRD, SEM, TEM, and BET were used to characterize the morphologies of these supports and the attached Pt catalyst. Electrochemical methods were used to measure both the ORR mass activity and stability of these materials. Improvement in both the specific area and conductivity were identified as the area for further development. Crown Copyright (c) 2012 Published by Elsevier Ltd. All rights reserved.