Synergistically Boosting the Durability of PtCo via Intermetallic Structure and Protective Layer Integration

초록

The development of cost-effective proton exchange membrane fuel cells has driven extensive research on reducing the reliance on costly platinum group metals (PGM) by employing Pt-M (M: transition metal) alloy catalysts for the oxygen reduction reaction. Despite progress, these catalysts still suffer from the dissolution of transition metals during continuous fuel cell operation. This study introduces a carbon shell-encapsulated, ordered PtCo nanocatalyst (Ord-PtCo), synthesized via a novel one-pot, two-stage annealing process, to address this issue. The integration of an ordered alloy structure with a protective carbon shell significantly enhances the catalytic activity and durability of the catalyst. In practical fuel cell tests with an ultralow Pt loading of 0.081 mgPGM cm-2 under H2-Air conditions, the Ord-PtCo achieved a current density of 0.311 A cm-2 at 0.8 V and a mass-specific rated power, normalized to Pt loading, of 8.89 W mgPGM -1 at 0.67 V, meeting the U.S. Department of Energy target for 2025. Furthermore, the catalyst demonstrated remarkable durability, registering only a 2 mV voltage loss under H2-O2 conditions and even a 6 mV voltage gain under H2-Air conditions after 30,000 cycles of accelerated degradation testing.

키워드