Atomically dispersed dual Fe centers on nitrogen-doped bamboo-like carbon nanotubes for efficient oxygen reduction
Ligang Ma, Junlin Li, Zhiwei Zhang, Hao Yang, Xueqin Mu, Xiangyao Gu, Huihui Jin, Ding Chen, Senlin Yan, Suli Liu, Shichun Mu
Abstract
Interfacial atomic configuration between dual-metal active species and nitrogen-carbon substrates is of great importance for improving the intrinsic activity of catalysts toward oxygen reduction reaction (ORR). Thus, from the atomic-scale engineering we develop a high intrinsic activity ORR catalyst in terms of incorporating atomically dispersed dual Fe centers (single Fe atoms and ultra-small Fe atomic clusters) into bamboo-like N-doped carbon nanotubes. Benefiting from atomically dispersed dual-Fe centers on the atomic interface of Fe-Nx/carbon nanotubes, the fabricated dual Fe centers catalyst exhibits an extremely high ORR activity (Eonset = 1.006 V; E1/2 = 0.90 V), beyond state-of-the-art Pt/C. Remarkably, this catalyst also shows a superior kinetic current density of 19.690 mA·cm−2, which is 7 times that of state-of-the-art Pt/C. Additionally, based on the excellent catalyst, the primary Zn-air battery reveals a high power density up to 137 mW·cm−2 and sufficient potential cycling stability (at least 25 h). Undoubtedly, given the unique structure-activity relationship of dual-Fe active species and metal-nitrogen-carbon substrates, the catalyst will show great prospects in highly efficient electrochemical energy conversion devices.