Proton exchange membrane fuel cells convert hydrogen and oxygen into electricity without emissions. The high cost and low durability of Pt-based electrocatalysts for the oxygen reduction reaction hinder their wide application, and the development of non-precious metal electrocatalysts is limited by their low performance. Here we design a hybrid electrocatalyst that consists of atomically dispersed Pt and Fe single atoms and Pt–Fe alloy nanoparticles. Its Pt mass activity is 3.7 times higher than that of commercial Pt/C in a fuel cell. More importantly, the fuel cell with a low Pt loading in the cathode (0.015 mg_Pt cm⁻²) shows an excellent durability, with a 97% activity retention after 100,000 cycles and no noticeable current drop at 0.6 V for over 200 hours. These results highlight the importance of the synergistic effects among active sites in hybrid electrocatalysts and provide an alternative way to design more active and durable low-Pt electrocatalysts for electrochemical devices.

质子交换膜燃料电池将氢气和氧气转化为电能而不会排放。Pt基电催化剂用于氧还原反应的高成本和低耐久性阻碍了其广泛应用，非贵金属电催化剂的发展受到其低性能的限制。在这里，我们设计了一种由原子分散的 Pt 和 Fe 单原子和 Pt-Fe 合金纳米粒子组成的混合电催化剂。其 Pt 质量活性是燃料电池中商业 Pt/C 的 3.7 倍。更重要的是，阴极中 Pt 负载量低的燃料电池（0.015 mg _Pt  cm ^-2) 具有出色的耐久性，在 100,000 次循环后具有 97% 的活性保持率，并且在 0.6 V 下超过 200 小时没有明显的电流下降。这些结果突出了混合电催化剂中活性位点之间协同效应的重要性，并为设计用于电化学装置的更活泼、更耐用的低 Pt 电催化剂提供了另一种方法。