Despite tremendous progress in catalyst development for rate-limiting cathodic oxygen reduction reaction (ORR), reducing Pt usage while meeting performance requirements in practical proton exchange membrane fuel cells (PEMFCs) remains a challenge. The ORR in PEMFCs occurs at a catalyst–electrolyte–gas three-phase interface. A desirable interface should exhibit highly active and available catalytic sites, as well as allow efficient oxygen and proton feeding to the catalytic sites and timely removal of water to avoid interface flooding. Here, we report the design of a three-phase microenvironment in PEFMCs, showing that carbon surface chemistry can be tuned to modulate its interaction with the ionomers and create favorable transport paths for rapid delivery of both reactants and products. With such an elaborate interfacial design, for the first time we have demonstrated PEMFCs with all key ORR catalyst performance metrics, including mass activity, rated power, and durability, surpassing the US Department of Energy targets.

尽管在用于限速阴极氧还原反应（ORR）的催化剂开发方面取得了巨大进展，但在满足实际质子交换膜燃料电池（PEMFC）的性能要求的同时，减少Pt用量仍然是一个挑战。PEMFC中的ORR发生在催化剂-电解质-气体的三相界面处。理想的界面应显示出高活性和可用的催化位点，并允许将有效的氧气和质子进料到催化位点并及时去除水以避免界面溢流。在这里，我们报告了P​​EFMCs中三相微环境的设计，表明可以调节碳表面化学性质以调节其与离聚物的相互作用，并为快速输送反应物和产物创造有利的运输途径。有了如此精致的界面设计，