Electrostatic Repulsion Activates Durable Pt Catalysts for HT‐PEMFCs

ABSTRACT High‐temperature proton exchange membrane fuel cells (HT‐PEMFCs) suffer from severe performance degradation caused by phosphoric acid (PA) poisoning, which remains a critical challenge for practical applications. Unlike conventional techniques, herein, an electrostatic repulsion strategy is proposed to mitigate this issue by repelling the primary poisoning species (H 2 PO 4 − ) away from Pt active sites through the construction of a local negative charge environment. To realize this concept, oxidized sulfur (SO x ) groups are precisely incorporated into carbon support to generate localized negative electrostatics around Pt. Spectroscopic analyses and density functional theory calculations reveal strong Pt‐support interactions that spatially enable electrostatic repulsion. As a result, the as‐prepared Pt/C‐S O catalyst exhibits high oxygen reduction reaction activity and outstanding durability in PA‐containing electrolytes, far outperforming commercial Pt/C. When applied in HT‐PEMFC, the Pt/C‐S O catalyst delivers a maximum power density of 1166 mW cm −2 and maintains stable operation for over 500 h of continuous operation at 500 mA cm −2 , with an ultra‐low voltage decay rate of 26 µV h −1 , which is nearly two orders of magnitude lower than that of commercial Pt/C (1075 µV h −1 ). This study provides a mechanistically grounded and practically feasible approach to overcoming PA poisoning and durability limitations of Pt‐based catalysts in HT‐PEMFCs.