Identifying key mononuclear Fe species for low-temperature methane oxidation
| Autor: | Chengwu Qiu, Aiqin Wang, Hongyu An, Daniela M. Farmer, Tao Yu, Bert M. Weckhuysen, Yuanshuai Liu, Wilm Jones, Pengfei Du, Weiyu Song, Andrew M. Beale, Wenhao Luo, Qian He, Zhi Li, Bing Yang |
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| Přispěvatelé: | Sub Inorganic Chemistry and Catalysis, Inorganic Chemistry and Catalysis |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Chemical Science Chemical Science, 12(9), 3152. Royal Society of Chemistry |
| ISSN: | 2041-6520 |
| Popis: | The direct functionalization of methane into platform chemicals is arguably one of the holy grails in chemistry. The actual active sites for methane activation are intensively debated. By correlating a wide variety of characterization results with catalytic performance data we have been able to identify mononuclear Fe species as the active site in the Fe/ZSM-5 zeolites for the mild oxidation of methane with H2O2 at 50 °C. The 0.1% Fe/ZSM-5 catalyst with dominant mononuclear Fe species possess an excellent turnover rate (TOR) of 66 molMeOH molFe−1 h−1, approximately 4 times higher compared to the state-of-the-art dimer-containing Fe/ZSM-5 catalysts. Based on a series of advanced in situ spectroscopic studies and 1H- and 13C- nuclear magnetic resonance (NMR), we found that methane activation initially proceeds on the Fe site of mononuclear Fe species. With the aid of adjacent Brønsted acid sites (BAS), methane can be first oxidized to CH3OOH and CH3OH, and then subsequently converted into HOCH2OOH and consecutively into HCOOH. These findings will facilitate the search towards new metal-zeolite combinations for the activation of C–H bonds in various hydrocarbons, for light alkanes and beyond. The monomeric Fe species in Fe/ZSM-5 have been identified as the intrinsic active sites for the low-temperature methane oxidation. |
| Databáze: | OpenAIRE |
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