Facile synthesis of ultra-stable Co-N-C catalysts using cobalt porphyrin and peptides as precursors for selective oxidation of ethylbenzene

Intramolecular coordination between cobalt and nitrogen in cobaltporphyrin and axial coordination between metal in porphyrin and nitrogen-enriched peptides are helpful to yield the stable Co-N-C catalysts with excellent catalytic performance. [Display omitted] •Co-N-C catalysts synthesized by heatin...

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Bibliographic Details
Published in:Molecular catalysis 2018-10, Vol.458, p.1-8
Main Authors: Jie, Shanshan, Yang, Congqiang, Chen, Yuan, Liu, Zhigang
Format: Article
Language:English
Subjects:
Co-N-C
Cobalt porphyrin
Ionic liquid
Peptides
Selective oxidation
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Summary:Intramolecular coordination between cobalt and nitrogen in cobaltporphyrin and axial coordination between metal in porphyrin and nitrogen-enriched peptides are helpful to yield the stable Co-N-C catalysts with excellent catalytic performance. [Display omitted] •Co-N-C catalysts synthesized by heating a homogenous solution of cobaltporphyrin/polypeptide/ionic liquid.•Metalloporphyrin with the metal-N4 structure preventing the aggregation of metal nanoparticles.•Axial coordination between cobalt in cobaltporphyrin and nitrogen in peptides to generate the active sites.•As-synthesized Co-N-C catalysts with remarkable stability for the oxidation of ethylbenzene. The highly dispersed active sites are desirable to optimize the atom efficiency. In this study, a series of novel cobalt grafted in N-doped carbon (Co-N-C) catalysts for selective oxidation of ethylbenzene are synthesized by heating a solution of cobalt porphyrin and peptides in ionic liquids, which are also characterized by techniques such as FT-IR, XRD, SEM-EDX, HR-TEM, and XPS. The results show that the as-prepared catalysts have an attractive catalytic performance, namely, 40% of ethylbenzene conversion and 75% of selectivity to acetophenone. Especially, the activity and selectivity of the as-prepared catalysts remain almost similar even after the 10th run. Moreover, the modified-complexometry method is verified to improve the dispersion of metal active sites. The remarkable catalytic performance of the as-prepared catalysts is attributed to the highly dispersed active sites and strong interactions between Co and N species in Co-Nx moieties.
ISSN:2468-8231
2468-8231
DOI:10.1016/j.mcat.2018.08.007