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Title: Impacts of Imidazolate Ligand on Performance of Zeolitic-Imidazolate Framework-Derived Oxygen Reduction Catalysts

Journal Article · · ACS Energy Letters

Carbon-hosted Fe-N-coordinated (Fe/N/C) materials, especially those derived from thermolysis of iron-added zinc-based zeoliteimidazolate frameworks (ZIFs), have emerged as the most promising platinum group metal-free (PGM-free) oxygen reduction reaction (ORR) catalysts. However, the impacts of the precursory ZIF structure and their conversion chemistry during thermal activation to the final catalytic activity remain to be further explored in the process of continuously refining the catalyst performance. In this work, we synthesized a series of Fe-doped ZIFs with different imidazolate ligands and systematically studied the correlation between the crystal structures with the final ORR catalytic activity in an alkaline electrolyte. We also investigated the ZIF decomposition chemistry during pyrolysis using a thermogravimetric mass-spectroscopic analysis. We demonstrated that imidazole side-chain substitution alters the ZIF's decomposition during pyrolysis, influencing the elemental compositions, surface properties, graphitization levels, and ultimately the catalytic performance. The Zn(mIm)2TPIBP catalyst affords the highest ORR activity with a half-wave potential of 0.93 V vs RHE, representing the best among all PGM-free catalysts studied.

Research Organization:
Argonne National Lab. (ANL), Argonne, IL (United States). Center for Nanoscale Materials
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Transportation Office. Fuel Cell Technologies Office; USDOE Office of Science (SC)
Grant/Contract Number:
AC02-06CH11357
OSTI ID:
1574899
Journal Information:
ACS Energy Letters, Vol. 4, Issue 10; ISSN 2380-8195
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 24 works
Citation information provided by
Web of Science