A gel-limiting strategy for large-scale fabrication of Fe-N-C single-atom ORR catalysts

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 9; no. 11; pp. 7137 - 7142
• Main Authors: Wang, Youpeng, Li, Qiulin, Zhang, Long-cheng, Wu, Yuanke, Chen, Hao, Li, Tianhao, Xu, Maowen, Bao, Shu-Juan
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 23.03.2021
• Subjects: Activated carbon; Catalysts; Constraining; Electrocatalysts; Fabrication; Immobilization; Metal air batteries; Open circuit voltage; Photoelectron spectroscopy; Photoelectrons; Scanning transmission electron microscopy; Single atom catalysts; Stability; Transition metals; Transmission electron microscopy; X ray photoelectron spectroscopy; Zinc-oxygen batteries
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d0ta09228b

Although transition metal single atom site catalysts (SASCs) show great potential for electrocatalysis, their large-scale controllable and flexible preparation remains a great challenge. In this article, we report a simple gel-limiting strategy for fabricating Fe-N-C single-atom catalysts and evaluate its feasibility in large-scale applications. The results show that the production of Fe-SASCs can be controlled by the limiting immobilization of a hydroxyl-rich temperature-controlled gel combined with simple centrifugal treatment, even if the amount of Fe-feeding fluctuates within a certain range. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray photoelectron spectroscopy (XPS) confirmed the formation of Fe-N single-atom sites and the uniform distribution of Fe on commercial activated carbon. As an ORR electrocatalyst, the Fe-SASC delivered a higher limiting diffusion current, and more positive onset potential and half-wave potential ( E onset = 1.00 V, E 1/2 = 0.87 V), and excellent methanol resistance compared to commercial Pt/C ( E onset = 0.97 V, E 1/2 = 0.85 V). Using the prepared Fe-SASCs, a homemade Zn-air battery was assembled which demonstrated a higher open circuit voltage, power density, and stability, further proving the practical application value of our proposed method and as-prepared catalyst. More importantly, our reported strategy can be further developed and extended to the future preparation of more transition metal SASCs. Although transition metal single atom site catalysts (SASCs) show great potential for electrocatalysis, their large-scale controllable and flexible preparation remains a great challenge.