Entropy-driven durability enhancement of PtM3 (M = transition metal) type alloy catalysts for the oxygen reduction reaction

Abstract

Low-platinum (low-Pt) alloys are widely regarded as a promising alternative to commercial Pt/C catalysts, owing to their excellent balance of cost reduction and enhanced catalytic performance. However, they have long been hindered by a critical challenge—poor durability—primarily stemming from the dissolution of non-noble metals. Herein, we report a series of high-performance, stable low-Pt high-entropy intermetallic catalysts with the composition Pt(FeCoNi)_3−xIn_x (where x = 0.25, 0.5, 0.75, 1), and systematically elucidate the role of entropy in regulating both the dissolution behavior of non-noble metals and the overall catalytic performance. The optimized high-entropy intermetallic Pt(FeCoNi)_2.5In_0.5 (PFCNI) exhibited significantly superior stability to its binary counterparts. PFCNI delivered an initial mass activity of 1.04 A mg_Pt⁻¹, with only a 14.3% loss after 30 000 accelerated durability test (ADT) cycles—outperforming both commercial Pt/C and the binary reference catalysts. When integrated into a membrane electrode assembly (MEA), PFCNI retained 74.1% of its maximum power density after 30 000 accelerated stress test (AST) cycles. In contrast, the MEA based on PtNi₃ (a binary counterpart) retained merely 16.8% of its maximum power density even after a shorter duration of 20 000 AST cycles. This study demonstrates that the high-entropy effect remarkably enhances the stability of typical PtM₃-type catalysts for the acidic oxygen reduction reaction (ORR), thereby offering a promising strategy for the development of low-Pt catalysts with long-term durability.