Dual confinement strategy for Pt–Co intermetallic electrocatalysts with superior durability in proton exchange membrane fuel cells

Abstract

Proton exchange membrane fuel cells (PEMFCs) are promising for the development of clean energy devices. However, their applications are hindered by the durability and high cost of Pt-based catalysts. Ordered intermetallic compounds (IMCs) offer enhanced activity and stability, but their synthesis typically requires high-temperature annealing, which leads to severe nanoparticle (NP) sintering. Herein, we develop a dual dopamine coating strategy to achieve PtCo IMCs with small particle sizes (<4 nm) and high ordering degrees (>63%). The first polydopamine-derived carbon layer confines the Pt–Co NPs during high-temperature reduction, while the second coating enables a moderate-temperature annealing step that promotes atomic ordering without compromising structural integrity. The resulting catalyst exhibits a remarkable half-wave potential (E_1/2) of 0.967 V versus RHE—a 75 mV improvement over commercial Pt/C—and retains nearly 100% of its initial mass activity after 40 000 accelerated durability tests. When integrated into a PEMFC cathode, the catalyst demonstrates excellent stability with only 10 mV voltage loss at 0.8 A cm⁻² after 30 000 cycles, surpassing the DOE 2025 target. The exceptional durability is attributed to the effects of spatial confinement and enhanced atomic ordering, which inhibits NP coalescence and metal dissolution. This work provides an effective route for synthesizing highly active and durable IMC electrocatalysts for PEMFC applications.