Molecular architectures of iron complexes for oxygen reduction catalysis—Activity enhancement by hydroxide ions coupling
Poe Ei Phyu Win1, Jiahui Yang1, Shuwang Ning2, Xiang Huang3,*, Gengtao Fu2, Qiming Sun1,4, Xing-Hua Xia5,*, and Jiong Wang1,4,*
1 Soochow Univ, Coll Chem, Innovat Ctr Chem Sci, Chem Engn & Mat Sci, Suzhou 215006, Peoples R China
2 Nanjing Normal Univ, Jiangsu Collaborat Innovat Ctr Biomed Funct Mat, Sch Chem & Mat Sci, Jiangsu Key Lab New Power Batteries, Nanjing 210023, Peoples R China
3 Southern Univ Sci & Technol, Dept Phys, Shenzhen 518055, Peoples R China
4 Soochow Univ, Jiangsu Key Lab Adv Negat Carbon Technol, Suzhou 215123, Jiangsu, Peoples R China
5 Nanjing Univ, Sch Chem & Chem Engn, State Key Lab Analyt Chem Life Sci, Nanjing 210023, Peoples R China
PNAS, 121, 11 (2024): e2316553121
Developing cost-effective and high-performance electrocatalysts for oxygen reduction reaction (ORR) is critical for clean energy generation. Here, we propose an approach to the synthesis of iron phthalocyanine nanotubes (FePc NTs) as a highly active and selective electrocatalyst for ORR. The performance is significantly superior to FePc in randomly aggregated and molecularly dispersed states, as well as the commercial Pt/C catalyst. When FePc NTs are anchored on graphene, the resulting architecture shifts the ORR potentials above the redox potentials of Fe2+/3+ sites. This does not obey the redox-mediated mechanism operative on conventional FePc with a Fe2+-N moiety serving as the active sites. Pourbaix analysis shows that the redox of Fe2+/3+ sites couples with HO- ions transfer, forming a HO-Fe3+-N moiety serving as the ORR active sites under the turnover condition. The chemisorption of ORR intermediates is appropriately weakened on the HO-Fe3+-N moiety compared to the Fe2+-N state and thus is intrinsically more ORR active.
链接：https://www.pnas.org/doi/10.1073/pnas.2316553121
