Carbon support engineering for mass transport and durability in PEMFC catalyst layers

Carbon support engineering is used to improve mass transport and long-term durability in proton-exchange membrane fuel cell (PEMFC) catalyst layers. This perspective reviews structural design approaches such as hierarchical pore architectures and graphitized core-shell composites, as well as surface functionalization with heteroatoms including N, F, and Br. These strategies are discussed in relation to oxygen and proton transport resistance, three-phase boundary formation, and ionomer distribution. Mechanistic insights from in situ characterization and modeling are used to connect carbon morphology and interfacial chemistry to carbon corrosion pathways and stability under electrochemical operation. This perspective provides a rationale for selecting support structures and functional groups to mitigate corrosion while maintaining efficient transport, supporting the development of scalable high-performance PEMFC systems.