Developing efficient electrocatalysts for direct ammonia fuel cells has been researched intensively. Herein, a Pt-NiO/C catalyst is prepared and applied to ammonia oxidation reaction (AOR). The introduction of NiO can decrease the average crystallite sizes and modify the electronic structure of Pt. Compared with Pt/C catalyst, as-prepared Pt-NiO/C presents the larger electrochemical surface area (ECSA), higher peak current density, lower activation energy and better stability for AOR. It suggests that Pt-NiO/C is a promising system for AOR in direct ammonia fuel cells. (C) 2017 The Electrochemical Society. All rights reserved.