PtRu alloy nanoparticles (NPs) in a commercial PtRu/C catalyst were encapsulated within few-layer graphitic boron nitride (h-BN) shells to form PtRu@h-BN/C core-shell catalysts, which were used as CO-tolerant anode catalyst in proton exchange membrane fuel cells (PEMFCs). Electrochemical results reveal that the PtRu@h-BN/C catalysts show similar activity in hydrogen oxidation reaction (HOR) as the PtRu/C catalysts but present enhanced CO-tolerance in fuel cell tests. Single cell performance with the PtRu@h-BN/C catalyst has been lowered by less than 20% with 30 ppm CO/25% CO2 introduced into H-2 feed gas, while the PtRu/C catalyst suffers from a decrease of 60% under the same conditions. The reaction data and characterization results suggest that h-BN ultrathin shells can achieve a good balance between durability and activity, enabling the PtRu@h-BN/C material to act as a potential anode catalyst for PEMFCs. (C) 2018 Elsevier B. V. All rights reserved.