Manganese Single-Atom-Engineered TiO2 Enables High-Performance Pt Catalysts for Proton Exchange Membrane Fuel Cells

Abstract The instability of carbon supports in platinum (Pt)-based catalysts under high potentials severely hinders the long-term performance of the corresponding proton exchange membrane fuel cells (PEMFCs). Developing robust oxide supports that can simultaneously stabilize Pt nanoparticles and regulate their intrinsic catalytic properties remains an important challenge. In this work, we report a single-atom engineering strategy to strengthen metal–support interactions and construct a Mn single-atom-modified TiO2-supported Pt catalyst (Pt/Mn1–TiO2) to significantly improve the performance of PEMFCs. The atomically dispersed Mn sites induce pronounced interfacial charge transfer, leading to an optimized electronic structure and a downshifted d-band center of Pt, thereby modulating the adsorption of oxygenated intermediates and enhancing intrinsic oxygen reduction reaction (ORR) activity. Meanwhile, the strengthened interfacial anchoring can effectively suppress Pt oxidation, migration, and agglomeration, resulting in a superior structural stability. As a result, Pt–Mn1/TiO2 exhibits a high half-wave potential of 0.937 V (vs RHE) and significantly enhanced mass/specific activities in acidic media. In a practical H2–O2 fuel cell, it delivers a peak power density of 2.37 W cm–2, outperforming commercial Pt/C, while maintaining minimal performance degradation during long-term operation. This work provides a general strategy for achieving synergistic enhancement of activity and durability in oxide-supported Pt catalysts via single-atom interfacial engineering.