Bai Jirong, Fu Yang, Zhou Pin, Xu Peng, Wang Lingling, Zhang Jianping, Jiang Xiankai, Zhou Quanfa, Deng Yaoyao
Research Center of Secondary Resources and Environment, School of Chemical Engineering and Materials, Changzhou Institute of Technology, Changzhou 213022, China.
ACS Appl Mater Interfaces. 2022 Jul 6;14(26):29986-29992. doi: 10.1021/acsami.2c08572. Epub 2022 Jun 26.
PGM-free (platinum group metal) electrocatalysts are intensively investigated and used as low-cost catalysts for the oxygen reduction reaction (ORR) in the field of fuel cells, but further studying their performance improvement methods and actual reaction mechanism is still a big a challenge. In this work, a novel eletrocatalyst containing atomically dispersed Mn/Fe single atoms (SAs) and Fe nanoparticles (NPs) on N-doped carbonaceous (nanosheet/nanotube hybrids) is fabricated via a simple pyrolysis method. This high-activity ORR electrocatalyst has higher half-wave potential ( = 0.91 V) and superior long-term durability in alkaline solutions and outperforms Pt/C catalysts, which can be ascribed to the synergetic interaction between Mn/Fe SAs and Fe-NPs. Fe/MnFe-NC-25 has stronger reactant adsorption ability and a lower dissociation energy barrier than Fe/Fe-NC, which is conducive to breaking the O-O bond and accelerating ORR kinetics. This work presents a method to synthesize carbon-based electrocatalysts with high ORR activity and stability and shows that a variety of active sites encapsulated in N-doped carbonaceous materials can be a class of competitive candidates for PGM-free electrocatalysts.
不含铂族金属（PGM）的电催化剂正在被深入研究，并被用作燃料电池领域中氧还原反应（ORR）的低成本催化剂，但进一步研究其性能改进方法和实际反应机理仍是一个巨大挑战。在这项工作中，通过一种简单的热解方法制备了一种新型电催化剂，该催化剂在氮掺杂碳质（纳米片/纳米管杂化物）上含有原子分散的Mn/Fe单原子（SAs）和Fe纳米颗粒（NPs）。这种高活性的ORR电催化剂在碱性溶液中具有更高的半波电位（= 0.91 V）和优异的长期耐久性，并且性能优于Pt/C催化剂，这可归因于Mn/Fe SAs与Fe-NPs之间的协同相互作用。与Fe/Fe-NC相比，Fe/MnFe-NC-25具有更强的反应物吸附能力和更低的解离能垒，这有利于打破O-O键并加速ORR动力学。这项工作提出了一种合成具有高ORR活性和稳定性的碳基电催化剂的方法，并表明封装在氮掺杂碳质材料中的各种活性位点可以成为不含PGM的电催化剂的一类有竞争力的候选物。
