CeO2 Nanoparticles Boosted Fe‐N‐C Sites Derived from Dual Metal Organic Frameworks toward Highly Active and Durable Oxygen Reduction Reaction. Issue 24 (27th July 2022)

• Record Type: Journal Article
• Authors: Qiu, Chenxi; Gao, Rui; Guo, Yizheng; Qin, Jiaqi; Zhang, Guanghui; Song, Yujiang
• Is Part Of: Advanced materials interfaces. Volume 9:Issue 24(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-07-27
• Subjects: dual metal organic frameworks -- durability of Fe‐N‐C -- oxygen reduction reaction; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.202200852
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: The durability improvement of Fe‐N‐C electrocatalysts toward acidic oxygen reduction reaction (ORR) remains a grand challenge. H2 O2 seriously degrades Fe‐N‐C sites, which account for a major origin of the low durability. Herein, the growth of hemin decorated zeolitic imidazole framework (hemin‐ZIF 8) on preformed Ce‐1, 3, 5‐benzenecarboxylic acid (Ce‐BTC) metal organic frameworks (MOFs) is reported. Interestingly, the resultant dual MOFs appear to be Ce‐BTC nanorods decorated with many hemin‐ZIF 8 dodecahedral nanocrystals, well resembling rice panicles. After pyrolysis, CeO2 nanoparticles are evenly distributed in carbonized nanorods and abundant Fe‐N‐C sites are embedded in shrunk dodecahedra, labeled as Fe‐N‐C‐CeO2 . Fe‐N‐C‐CeO2 exhibits a high ORR activity in terms of a half wave potential (E1/2 ) of 0.800 V (vs RHE). The high ORR activity is closely correlated with the well exposure of Fe‐N‐C sites. In addition, the presence of CeO2 leads to a low H2 O2 yield of Fe‐N‐C‐CeO2 (2.3%), much lower than that of Fe‐N‐C (4.3%) by itself in the absence of CeO2 . After 5000 potential cycling, the E1/2 of Fe‐N‐C‐CeO2 degrades 15 mV superior to that of Fe‐N‐C (42 mV). Moreover, a single cell with Fe‐N‐C‐CeO2 as cathode degrades much slower than that of Fe‐N‐C (28 000 s vs 7200 s) during chronoamperometric measurements. Abstract : Hemin modified ZIF‐8 nanocrystals are selectively grown on Ce‐1, 3, 5‐benzenecarboxylic acid nanorods to obtain "rice panicles" like dual metal organic frameworks (MOFs). CeO2 nanoparticles modified Fe‐N‐C ORR electrocatalyst is prepared by pyrolysis of the dual MOFs. The high Ce 3+ content of CeO2 is contributed to scavenge H2 O2, so as to significantly improve the durability of Fe‐N‐C electrocatalyst in rotating disk electrode and single cell tests.