Hollow COF-derived carbon supports enable PtCo alloy catalysts with exceptional activity and durability for oxygen reduction reaction in fuel cells

The development of high-performance and durable oxygen reduction reaction catalysts under harsh working environments remains a key challenge in advancing proton exchange membrane fuel cells. Here, we report a series of hollow-structured covalent organic framework-derived carbon as support materials for PtCo alloy nanocatalysts. These hollow architectures provide unique spatial confinement and encapsulation effects, which not only facilitate efficient mass transport but also protect active sites from degradation in acidic media, thereby ensuring simultaneous enhancement in activity and stability. The optimized PtCo@NC TAPBT catalyst delivers a peak power density of 1.23 W cm −2 under H 2 -Air conditions and a mass activity of 1.06 A mg Pt −1 at 0.9 V, representing 2.41 times higher than that of commercial Pt/C (0.40 A mg Pt −1 ). Moreover, the fuel cell assembled with this catalyst exhibits outstanding durability, showing a voltage degradation of only 8 mV after 30000 cycles at 0.8 A cm −2 and a mass activity retention of 87.7% (0.93 A mg Pt −1 ). Notably, this performance exceeds the U.S. Department of Energy’s 2025 initial mass activity target (0.44 A mg Pt −1 ) by a factor of 2.1, highlighting the potential of HCOF-derived carbon materials for next-generation fuel cell applications.