High-performance long-term driving proton exchange membrane fuel cell implemented with chemically ordered Pt-based alloy catalyst at ultra-low Pt loading.

In proton exchange membrane fuel cells (PEMFCs), it is very important to develop a cathode catalyst with high oxygen reduction reaction activity and high chemical stability while reducing the Pt content. Alloying Pt with transition metals is one of options to achieve this goal, but it generally suffers from stability issues caused by transition metals. We demonstrate a mass-producible carbon layer-protected and chemically ordered PtFe alloy cathode nanocatalyst of about 4 nm size with high activity, stability, and Pt utilization efficiency. The catalyst is prepared via a facile and easily scaled synthesis route where the formation of PtFe nanoparticles, phase transition from chemically disordered to chemically ordered PtFe phase, and carbon layer-covering occurs simultaneously. The synthesized catalyst with the highest degree of phase transition to chemically ordered PtFe achieves a mass activity of 848 A g Pt −1 at 0.9 V on rotating disk electrode, and maintains its performance over 30,000 stability test cycles. The PEMFC with this catalyst also stably performs 0.8 A cm−2 at 0.66 V (1.1 A cm−2 at 0.6 V) over 30,000 stability test cycles at an ultra-low total Pt loading of 0.100 mg Pt cm−2, far exceeding the 2025 US Department of Energy (DOE) stability target. [Display omitted] • A carbon-layer-protected fct -PtFe nanocatalyst for ORR is synthesized. • The catalyst maintains high fuel cell performance over 30,000 cycles. • The performance of the fuel cell surpasses the 2025 DOE target. • The facile synthesis route enables the mass production of the catalysts. [ABSTRACT FROM AUTHOR]