Electrospinning Machine| Molecular engineering and channel structure modulation for single-atom iron-embedded high-porosity carbon fibers with enhanced oxygen reduction reaction and zinc-air battery performance

Iron-based electrocatalysts demonstrate great potential to replace precious metal materials in the oxygen reduction reaction (ORR) catalytic systems of zinc-air batteries (ZABs), owing to their unique electronic structures and abundant reserves. Particularly, Fe-N4 single-atom catalysts (SACs) have broken through the performance limitations of traditional catalysts with their atomically dispersed active sites and well-defined coordination structures. However, precisely controlling the coordination configuration of Fe-N4 SACs remains challenging, while conventional Fe-N-C catalysts also suffer from mass transfer limitations and low active site utilization due to dense carbon matrices.

To address these challenges, Associate Professor Shen Mengxia's research group from the Academician Innovation Team of "Biomass Chemistry and Materials" at Shaanxi University of Science and Technology published a research paper titled "Molecular engineering and channel structure modulation for single-atom iron-embedded high-porosity carbon fibers with enhanced oxygen reduction reaction and zinc-air battery performance" in the Journal of Colloid and Interface Science.The study innovatively proposed an electrospinning strategy integrating molecular engineering with directional hollow-channel pore structure modulation, successfully constructing a single-atom iron-anchored highly porous carbon fiber catalyst (FeSA@HPCF). The core design concept of this system lies in two key aspects

Benefiting from these distinctive structural advantages, the FeSA@HPCF catalyst demonstrates exceptional ORR activity (E1/2 = 0.87 V) and four-electron selectivity. Furthermore, liquid ZABs assembled with FeSA@HPCF exhibit outstanding maximum power density (186 mW cm-2) and cycling durability lasting 275 hours, while the assembled all-solid-state ZABs also display superior electrochemical performance.

Fig. 1. Structural and compositional characterization of FeSA@HPCF.

Fig. 2. Structural analysis of FeSA@HPCF.

Fig. 3. ORR performance evaluation.

Fig. 4. Liquid ZAB performance with FeSA@HPCF.

Fig. 5. All-solid-state ZAB performance with FeSA@HPCF.

In summary, through an electrospinning strategy combining molecular engineering with directional hollow-channel pore structure modulation, we successfully constructed a single-atom iron-anchored highly porous carbon fiber catalyst (FeSA@HPCF). This approach achieves both precise replication of the Fe-N4 active center structure and hierarchical regulation of pore architectures. Benefiting from these unique structural advantages, the FeSA@HPCF catalyst demonstrates exceptional ORR activity (E1/2 = 0.87 V) and four-electron selectivity.This study has accomplished molecular-level precision control that not only enables customizable construction of Fe-N4 catalyst microstructures, but more importantly overcomes the inherent dense carbon matrix limitations of conventional iron-based catalysts. The work establishes a versatile design platform with both flexibility and universality for optimizing oxygen reduction reaction (ORR) performance.

These research findings have been published in the Journal of Colloid and Interface Science under the title "Molecular engineering and channel structure modulation for single-atom iron-embedded high-porosity carbon fibers with enhanced oxygen reduction reaction and zinc-air battery performance". Associate Professor Shen Mengxia from Shaanxi University of Science and Technology serves as the corresponding author, with Master's student Xie Liangjiao as the primary contributor. Professor Yonghao Ni from the University of New Brunswick, Canada and Yujun Liu from Shaanxi Yuanfeng New Materials Technology Co., Ltd. participated as collaborating researchers.This work was supported by the National Natural Science Foundation of China (No. 22108164), Shaanxi Key Research and Development Program (No. 2024GX-YBXM-339, No. 2025CY-YBXM-387), and Shaanxi High-Level Talent Program.

Article link:https://doi.org/10.1016/j.jcis.2025.138230