期刊
ADVANCED SCIENCE
卷 9, 期 20, 页码 -出版社
WILEY
DOI: 10.1002/advs.202200592
关键词
carbon dissolution; environmental transmission electron microscope; molten nanoparticles; single-atom catalyst; structure evolution
资金
- National Natural Science Foundation of China [92161124, 52002165]
- National Key Research and Development Program of China [2021YFA0717400]
- Beijing National Laboratory for Molecular Sciences [BNLMS202013]
- Shenzhen Basic Research Project [JCYJ20210324104808022]
- Guangdong Provincial Natural Science Foundation [2021A1515010229]
- Guangdong Provincial Innovation Project [2019KTSCX155]
- SUSTech
- Shenzhen Nobel Prize Scientists Laboratory Project [C17783101, C17213101]
- Guangdong Provincial Key Laboratory of Energy Materials for Electric Power [2018B030322001]
- Key Research Plan of Shenzhen
- Post-doctorate Scientific Research Fund [K21217502]
- Guangdong Provincial Key Laboratory of Catalysis [2020B121201002]
The evolution process of Co single-atom catalysts during pyrolysis is studied in this paper. The results show that carbon dissolution and melting/sublimation-driven structural dynamics have a significant impact on the catalyst performance, and a highly selective catalyst for the oxidation of aromatic alkanes is obtained.
Transition metal single-atom catalysts (SACs) are of immense interest, but how exactly they are evolved upon pyrolysis of the corresponding precursors remains unclear as transition metal ions in the complex precursor undergo a series of morphological changes accompanied with changes in oxidation state as a result of the interactions with the carbon support. Herein, the authors record the complete evolution process of Co SAC during the pyrolysis a Co/Zn-containing zeolitic imidazolate framework. Aberration-corrected environmental TEM coupled with in-situ EELS is used for direct visualization of the evolution process at 200-1000 degrees C. Dissolution of carbon into the nanoparticles of Co is found to be key to modulating the wetting behavior of nanoparticles on the carbon support; melting of Co nanoparticles and their motion within the zeolitic architecture leads to the etching of the framework structure, yielding porous C/N support onto which Co-single atoms reside. This uniquely structured Co SAC is found to be effective for the oxidation of a series of aromatic alkanes to produce selective ketones among other possible products. The carbon dissolution and melting/sublimation-driven structural dynamics of transition metal revealed here will expand the methodology in synthesizing SACs and other high-temperature processes.
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