Orbital hybridization to regulate the electronic structures and surface chemisorption properties of transition metals is of great importance for boosting the oxygen reduction reaction (ORR) in proton-exchange membrane fuel cells (PEMFCs). Herein, we developed a core–shell rambutan-like nanocarbon catalyst (FeAl-RNC) with atomically dispersed Fe–Al atom pairs from metal–organic framework (MOF) material. Experimental and theoretical results demonstrate that the strong p–d orbital hybridization between Al and Fe results in an asymmetric electron distribution with moderate adsorption strength of oxygen intermediates, rendering enhanced intrinsic ORR activity. Additionally, the core–shell rambutan-like structure of FeAl-RNC with abundant micropores and macropores can enhance the density of active sites, stability, and transport pathways in PEMFC. The FeAl-RNC-based PEMFC achieves excellent activity (68.4 mA cm^–2 at 0.9 V), high peak power (1.05 W cm^–2), and good stability with only 7% current loss after 100 h at 0.7 V under H₂–O₂ condition.

中文翻译：

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通过与 Al 掺杂剂的 p-d 杂化实现原子 Fe 位点的高效质子交换膜燃料电池性能

轨道杂化调节过渡金属的电子结构和表面化学吸附特性对于促进质子交换膜燃料电池（PEMFC）中的氧还原反应（ORR）具有重要意义。在此，我们开发了一种核壳类红毛丹纳米碳催化剂（FeAl-RNC），其具有来自金属有机骨架（MOF）材料的原子分散的Fe-Al原子对。实验和理论结果表明，Al 和 Fe 之间强烈的 p-d 轨道杂化导致不对称电子分布，氧中间体的吸附强度适中，从而增强了内在的 ORR 活性。此外，FeAl-RNC的核壳红毛丹结构具有丰富的微孔和大孔，可以提高PEMFC中活性位点的密度、稳定性和传输途径。基于FeAl-RNC的PEMFC具有优异的活性（0.9 V时为68.4 mA cm ^–2）、高峰值功率（1.05 W cm ^{–2 ）和良好的稳定性，在H} ₂下0.7 V下100小时后电流损失仅为7% –O ₂条件。