The development of catalysts free of platinum-group metals and with both a high activity and durability for the oxygen reduction reaction in proton exchange membrane fuel cells is a grand challenge. Here we report an atomically dispersed Co and N co-doped carbon (Co–N–C) catalyst with a high catalytic oxygen reduction reaction activity comparable to that of a similarly synthesized Fe–N–C catalyst but with a four-time enhanced durability. The Co–N–C catalyst achieved a current density of 0.022 A cm⁻² at 0.9 V_iR-free (internal resistance-compensated voltage) and peak power density of 0.64 W cm⁻² in 1.0 bar H₂/O₂ fuel cells, higher than that of non-iron platinum-group-metal-free catalysts reported in the literature. Importantly, we identified two main degradation mechanisms for metal (M)–N–C catalysts: catalyst oxidation by radicals and active-site demetallation. The enhanced durability of Co–N–C relative to Fe–N–C is attributed to the lower activity of Co ions for Fenton reactions that produce radicals from the main oxygen reduction reaction by-product, H₂O₂, and the significantly enhanced resistance to demetallation of Co–N–C.

对于质子交换膜燃料电池中的氧还原反应而言，开发不含铂族金属并且具有高活性和耐久性的催化剂是一个巨大的挑战。在这里，我们报告了一种原子分散的Co和N共掺杂碳（Co–N–C）催化剂，其催化氧还原反应活性与相似合成的Fe–N–C催化剂相当，但具有四倍的耐用性。Co-N–C催化剂在无0.9 V _iR（内部电阻补偿电压）的情况下达到了0.022 A cm ^-2的电流密度，在1.0 bar H ₂ / O _2下的峰值功率密度为0.64 W cm ^-2。燃料电池，高于文献报道的非铁铂族金属无催化剂。重要的是，我们确定了金属（M）–NC催化剂的两种主要降解机理：自由基对催化剂的氧化作用和活性部位的脱金属作用。Co–N–C相对于Fe–N–C的增强的耐久性归因于Co离子对Fenton反应的活性较低，Fenton反应从主要的氧还原反应副产物H ₂ O ₂产生自由基，并且显着增强Co-NC的抗脱金属性。