Fe–N/C catalysts with tunable mesoporous structures and carbon layer numbers reveal the role of interlayer O2 activation
- Title
- Fe–N/C catalysts with tunable mesoporous structures and carbon layer numbers reveal the role of interlayer O2 activation
- Authors
- Woo, Jinwoo; Lim, June Sung; Lim, Taejung; Baek, Du San; Kim, Jae Hyung; Lee, Jong Hoon; Jeong, Hu Young; Choi, Chang Hyuck; Joo, Sang Hoon
- Date Issued
- 2023-01
- Publisher
- The Royal Society of Chemistry
- Abstract
- A class of Fe,N-codoped carbon (Fe–N/C) electrocatalysts has made remarkable advances as highly promising non-Pt group metal catalysts for the oxygen reduction reaction (ORR). However, the design of Fe–N/C catalysts whose active site structure and O2 activation mode mimic those of an enzymatic ORR catalyst still remains a challenge. Herein, we report the preparation of mesoporous Fe–N/C catalysts with tunable tube- or rod-like frameworks and carbon layer numbers via solid-state nanocasting of mesoporous silica with an iron–phenanthroline complex. The tube-type Fe–N/C exhibited a larger surface area and active site density than the rod-type Fe–N/C. Unexpectedly, the rod-type Fe–N/C showed superior ORR activity to the tube-type Fe–N/C, with a smaller overpotential, greater turnover frequency (TOF), and lower Tafel slope. Temperature-programmed desorption studies revealed a weaker binding strength of the rod-type Fe–N/C with O2. The rod-type Fe–N/C consisting of multiple carbon layers is likely to activate O2 in the interlayer between the Fe–Nx-containing carbon layers, reminiscent of the enzymatic catalyst, whereas in the tube-type Fe–N/C with 3–4 carbon layers, O2 is mostly activated at a single Fe center on the external carbon layer. As a result, the TOF of the rod-type Fe–N/C exceeded those of reported catalysts. We envisage that our work can provide a new insight into the design of highly active Fe–N/C catalysts.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/115465
- DOI
- 10.1039/d2ey00055e
- ISSN
- 2753-801X
- Article Type
- Article
- Citation
- EES Catalysis, vol. 1, no. 1, page. 62 - 73, 2023-01
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