On the role of Zn and Fe doping in nitrogen-carbon electrocatalysts for oxygen reduction  

作　　者：Yanan Zou Yuanyuan Su Yongchao Yu Jinliang Luo Xiaomin Kang Jun Zhang Linghan Lan Tianshi Wang Jun Li 

机构地区：[1]College of Mechanical Engineering, University of South China, Hengyang, 421001, China [2]Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education of China, Chongqing, 400044, China [3]College of New Energy, Zhengzhou University of Light Industry, Zhengzhou, 450002, China [4]School of Mechanical and Electrical Engineering, Guilin University of Electronic Technology, Guilin, 541004, China

出　　处：《Nano Research》2024年第11期9564-9572,共9页纳米研究（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.52306248);Natural Science Foundations of Hunan Province of China(Nos.2024JJ6387 and 2024JJ6370);Scientific Research Foundation of the University of South China(Nos.230XQD020 and 230XQD021);Natural Science Foundation of Chongqing of China(No.CSTB2023NSCQ-MSX0926).

摘　　要：Zn is a frequently used and sometimes even an inevitably involved element (when zeolitic imidazolate framework-8 (ZIF-8) is adopted as the precursor) for preparing high-performance Fe-N-C oxygen reduction reaction (ORR) catalysts. However, how the Zn element affects the physicochemical architecture of the catalysts, how it enhances the catalytic activity and whether Zn atoms serve as the active centers remain unclear. Herein, we proposed a novel route that adopted pyrrole as the precursor and flexibly controlled the addition of exogenous Zn and Fe dopants before pyrrole polymerization. In this way, a series of nitrogen-carbon catalysts with or without Zn or Fe doping were synthesized. The detailed characterization revealed the role of Zn and Fe doping in the catalyst morphology, pore structure, active site configurations, ORR catalytic activity and fuel cell performance. Importantly, the findings revealed that Zn doping has little effect on the ORR mechanism and pathway. It enhances ORR activity primarily by increasing the number of active sites via introducing more micro- and meso-pores, rather than by creating new active sites. While Fe doping participated in forming both pores and active site centers. Moreover, the catalyst that co-doped with Zn and Fe atoms (Zn-FeNC), synthesized via this simple and template-free route we proposed, presented a unique hollow and hierarchical pore structure with highly boosted ORR activity. It exhibited a 40 mV higher E 1/2 value than Pt/C in alkaline media, along with a rapid current response in air-cathode of the direct formate fuel cell. These results are valuable in guiding the synthesis of high-performance Fe-N-C catalysts.

关 键 词：oxygen reduction reaction Fe-N-C catalysts hollow porous nanocarbon Zn doping direct formate fuel cell 

分 类 号：O64[理学—物理化学]