A Two‐in‐One Strategy to Simultaneously Boost the Site Density and Turnover Frequency of Fe−N−C Oxygen Reduction Catalysts

• DOI: 10.1002/ange.202425196
• Publication Date: 2025-01-14T08:39:31Z
• Authors: Jianbin Liu; Yao Liu; Bing Nan; Dashuai Wang; Christopher Allen; Zhichao Gong; Guanchao He; Kaixing Fu; Gonglan Ye; Huilong Fei
• Keywords: Turnover number

Site density and turnover frequency are the two fundamental kinetic descriptors that determine oxygen reduction activity of iron‐nitrogen‐carbon (Fe−N−C) catalysts. However, it remains a grand challenge to simultaneously optimize these parameters in single Fe−N−C catalyst. Here we show treating typical catalyst with ammonium iodine (NH4I) vapor via one‐step chemical deposition process not only increases surface area porosity (and thus enhanced exposure active sites) etching effect in‐situ released NH3, but also regulates electronic structure Fe−N4 moieties by dopants incorporated into carbon matrix. As result, NH4I‐treated possesses both high values site 2.15×1019 sites g−1 (×2 enhancement compared untreated counterpart) 3.71 electrons site−1 s−1 (×3 enhancement) correspond mass 12.78 A g−1, as determined nitrite stripping technique. Moreover, this exhibits an excellent base half‐wave potential (E1/2) 0.924 V acceptable acid E1/2 = 0.795 V, superior power 249.1 mW cm−2 zinc‐air batteries.