Development of platinum group metal (PGM)-free catalysts for oxygen reduction reaction (ORR) is essential for affordable proton exchange membrane fuel cells. Herein, a new type of atomically dispersed Co doped carbon catalyst with a core–shell structure has been developed via a surfactant-assisted metal–organic framework approach. The cohesive interactions between the selected surfactant and the Co-doped zeolitic imidazolate framework (ZIF-8) nanocrystals lead to a unique confinement effect. During the thermal activation, this confinement effect suppressed the agglomeration of Co atomic sites and mitigated the collapse of internal microporous structures of ZIF-8. Among the studied surfactants, Pluronic F127 block copolymer led to the greatest performance gains with a doubling of the active site density relative to that of the surfactant-free catalyst. According to density functional theory calculations, unlike other Co catalysts, this new atomically dispersed Co–N–C@F127 catalyst is believed to contain substantial CoN₂₊₂ sites, which are active and thermodynamically favorable for the four-electron ORR pathway. The Co–N–C@F127 catalyst exhibits an unprecedented ORR activity with a half-wave potential (E_1/2) of 0.84 V (vs. RHE) as well as enhanced stability in the corrosive acidic media. It also demonstrated high initial performance with a power density of 0.87 W cm⁻² along with encouraging durability in H₂–O₂ fuel cells. The atomically dispersed Co site catalyst approaches that of the Fe–N–C catalyst and represents the highest reported PGM-free and Fe-free catalyst performance.

中文翻译：

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由表面活性剂辅助的MOF衍生的 高活性原子分散的CoN ₄燃料电池阴极催化剂：碳壳限制策略†

对于可负担得起的质子交换膜燃料电池，开发用于氧还原反应（ORR）的不含铂族金属（PGM）的催化剂至关重要。在这里，已经开发了一种新型的具有核-壳结构的原子分散的掺Co碳催化剂。表面活性剂辅助的金属有机框架方法。所选表面活性剂和共掺杂的沸石咪唑酸酯骨架（ZIF-8）纳米晶体之间的内聚相互作用导致独特的封闭效应。在热活化过程中，这种限制作用抑制了Co原子位的团聚并减轻了ZIF-8内部微孔结构的塌陷。在所研究的表面活性剂中，相对于不含表面活性剂的催化剂，Pluronic F127嵌段共聚物可实现最大的性能提升，且活性位点密度增加一倍。根据密度泛函理论计算，与其他Co催化剂不同，这种新型原子分散的Co–N–C @ F127催化剂被认为含有大量的CoN _{2 + 2}这些位点对于四电子ORR途径是活跃的，并且在热力学上是有利的。Co–N–C @ F127催化剂具有空前的ORR活性，半波电势（E _1/2）为0.84 V（相对于RHE），并在腐蚀性酸性介质中具有更高的稳定性。它还显示出高初始性能，功率密度为0.87 W cm ^-2，并且在H ₂ -O ₂燃料电池中具有令人鼓舞的耐用性。原子分散的Co中心催化剂接近Fe–N–C催化剂，代表了报道的最高无PGM和无Fe催化剂性能。