Advanced carbon architectures for Pt-based oxygen reduction electrocatalysts in polymer electrolyte membrane fuel cells.

Polymer electrolyte membrane fuel cells (PEMFCs) represent a promising platform for clean energy conversion, generating electricity through the hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR) with high efficiency and near-zero emissions. However, the sluggish ORR at the cathode remains the dominant kinetic limitation hindering the widespread commercialization of PEMFCs. Recent studies suggest that carbon supports play a far more active role than simply providing electrical conductivity, as they can also influence catalytic ORR activity, durability, and mass transport efficiency. In conventional Pt-based catalysts, electrochemical carbon corrosion under harsh fuel cell operating conditions triggers nanoparticle detachment, agglomeration, Ostwald ripening, and dissolution, ultimately causing severe losses in electrochemically active surface area and overall fuel cell performance. This review highlights recent advances in the architectural design of carbon supports for Pt-based ORR electrocatalysts in PEMFCs, focusing on three principal strategies: (i) nitrogen-mediated structural modulation, (ii) nanoparticle-support interfacial anchoring, and (iii) protective carbon encapsulation. Particular emphasis is placed on the understanding of how these engineered carbon architectures mitigate carbon corrosion and enhance Pt stability. The insights discussed herein aim to provide rational design principles for next-generation carbon supports that enable highly active and durable ORR electrocatalysts in PEMFC technologies.