Atomically dispersed FeN4 and Fe2P nanoparticles anchored in N, P-codoped hollow porous carbon for efficient oxygen reduction reaction

• Published in: Fuel (Guildford) 2025-01, Vol.380, p.133072, Article 133072
• Main Authors: Wang, Yinghua, Wu, Lingmin, Qu, Konggang, Li, Baitao
• Format: Article
• Language: English
• Subjects: Fe-N4 single atomic sites; Fe2P nanoparticles; Microbial fuel cell; Oxygen reduction reaction; Zinc-air battery
• ISSN: 0016-2361
• DOI: 10.1016/j.fuel.2024.133072

A feasible assembling-trapping-bonding engineering strategy is proposed to guide the synthesis of the catalyst by introducing phosphorus functional groups and iron into a three-dimensional hollow layered porous carbon structure derived from a metal–organic framework. Due to this unique structure and the synergistic effect between Fe2P nanoparticle and single atomic FeN4, the catalyst exhibits excellent ORR catalytic activity and outstanding stability. In addition, the catalyst has demonstrated good practical applications in zinc-air battery (ZAB) and microbial fuel cell (MFC). [Display omitted] •Workable assembling-trapping-bonding engineering strategy.•Fe-N4 single-atom sites and Fe2P nanoparticles encapsulated in N, P-codoped carbon.•High oxygen reduction reaction activity in alkaline condition with half-wave potential of 0.91 V.•Power densities of 526 mW cm−2 and 3122 ± 102 mW m−2 in ZAB and MFC. The combination of single atoms and nanoparticles has shown promising activity toward oxygen reduction reaction (ORR). Herein, one workable assembling-trapping-bonding engineering strategy is proposed to introduce phosphorus functional groups and iron into hollow hierarchical porous carbon structure derived from Zeolitic imidazolate framework-8. The fabricated Fe2P/FeNPC catalyst contains Fe2P nanoparticles encapsulated in N, P-codoped carbon and abundant Fe-N4 single-atom sites, which presents exceptional ORR catalytic activity and outstanding stability. This feature is attributable to the unique mesoporous architecture, high nitrogen doping level, large specific surface area and the synergistic effect between Fe2P and Fe-N4 components. As expected, the optimized Fe2P/FeNPC displays half-wave potentials of 0.91, 0.78, and 0.70 V in alkaline, acidic, and neutral solutions, sequentially, as well as better four-electron pathway, superior methanol tolerance, and great long-term stability. The Zn-air battery (ZAB) with the Fe2P/FeNPC as the cathode catalyst deliver high capacity of 797 mAh gzn-1, superior power density of 526 mW cm−2 and excellent charge/discharge cycle stability of more than 150 h at 10 mA cm−2. Similarly, Fe2P/FeNPC reveals notable catalytic activity in microbial fuel cell (MFC), which exhibits an ultra-high open circuit voltage of 1018 ± 15 mV with a remarkable power density of 3122 ± 102 mW m−2. This work provides an effective method to introduce different components in effective pH-universal ORR catalyst to improve the catalytic activity and s