Here we report a new strategy to enhance the ORR activity of valve-metal-oxide electrocatalysts by combining an aliovalent cation Fe) with ZrO2 (particle size <10 nm). This results in a strong increase of the ORR activity, which is clearly higher than that obtained by the individual components. The highest ORR activity for a carbon supported ZrO2 catalyst with 12 wt% ZrO2 is observed upon the addition of 0.36-1.0 wt% Fe ( Fe/Zr atomic ratios of 0.02-0.08). (C) The Author(s) 2017. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: [email protected]. All rights reserved.