Sun Ning, Ru Sen, Zhang Chao, Liu Wei, Luo Qiquan, Jiao Jiqing, Lu Tongbu
MOE International Joint Laboratory of Materials Microstructure, Institute for New Energy Materials and Low Carbon Technologies, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384, China.
Haihe Laboratory of Sustainable Chemical Transformations, Tianjin 300192, China.
Fundam Res. 2022 Aug 9;5(4):1488-1494. doi: 10.1016/j.fmre.2022.07.014. eCollection 2025 Jul.
As potential alternatives to Pt-based catalysts for oxygen reduction reaction (ORR), iron (Fe)-based single-atomic site catalysts (SACs) have shown superior performances compared with others. For Fe SACs, the effect of directly coordinating N atoms has received intensive discussion, yet by contrast, the effect of secondary coordinating atoms has been left largely unexplored. Here, we developed a route to tuning externally doped N around Fe SACs to boost ORR activity. Density functional theory (DFT) calculations established the four different models for FeN for ORR, indicating that the FeN-PR-GN (pyrrolic-N for the first coordination shell and graphitic-N for the second coordination shell) can effectively improve the ORR performance. On the basis of theoretical calculations, we developed a two-step strategy including interior encapsulation and surface adsorption, which helped to regulate the different external coordination N of Fe SACs. The best-performing catalyst, FeN-PR-GN, displays excellent ORR performances in alkaline electrolytes; in particular, the catalyst gives a half-wave potential of 0.92 V ( RHE) and high stability, which is much better than those of commercial Pt/C. Our work here not only demonstrates an efficient catalyst to boost ORR performances, but also develops a facile strategy for the preparation of SACs for advanced fuel cells.
作为氧还原反应（ORR）中基于铂的催化剂的潜在替代品，铁（Fe）基单原子位点催化剂（SACs）已显示出优于其他催化剂的性能。对于铁单原子位点催化剂，直接配位氮原子的作用已得到深入讨论，然而相比之下，二级配位原子的作用在很大程度上尚未得到探索。在此，我们开发了一种调节铁单原子位点催化剂周围外部掺杂氮的方法，以提高氧还原反应活性。密度泛函理论（DFT）计算建立了用于氧还原反应的四种不同的铁氮模型，表明FeN-PR-GN（第一配位层为吡咯氮，第二配位层为石墨氮）可以有效提高氧还原反应性能。基于理论计算，我们开发了一种包括内部封装和表面吸附的两步策略，有助于调节铁单原子位点催化剂不同的外部配位氮。性能最佳的催化剂FeN-PR-GN在碱性电解质中表现出优异的氧还原反应性能；特别是，该催化剂的半波电位为0.92 V（相对于可逆氢电极）且具有高稳定性，远优于商业铂碳催化剂。我们在此的工作不仅展示了一种提高氧还原反应性能的高效催化剂，还开发了一种制备用于先进燃料电池的单原子位点催化剂的简便策略。
