Sulfur-confinement synthesis of an L10-PtZn intermetallic catalyst for enhanced oxygen reduction

Abstract

Proton exchange membrane fuel cells (PEMFCs) are promising for mobile and renewable energy storage due to their high efficiency and zero-carbon emissions. However, the slow kinetics of the oxygen reduction reaction (ORR) at the cathode remains a significant challenge. In this work, we successfully synthesized an L1₀-PtZn intermetallic compound (IMC) with a core–shell structure using a thiourea molecule-assisted strategy based on strong metal–support interactions with Pt–S bonding. The as-prepared PtZn-IMC catalyst exhibited significantly enhanced oxygen reduction reaction (ORR) performance, achieving a mass activity (MA) of 1.50 A mg_Pt⁻¹, approximately six-fold higher than that achieved by commercial Pt/C nanoparticles. Moreover, the catalyst demonstrated remarkable stability, retaining 93% of MA in rotating disk electrode (RDE) tests and showing only a 7.9% peak power density loss in membrane electrode assembly (MEA) measurements. Density functional theory (DFT) calculations reveal that the ordered PtZn structure lowered the Pt d-band center, improving the ORR kinetics and structural stability. This work demonstrates the potential of core–shell structure PtZn-IMC as an efficient and stable catalyst for PEMFC applications.