Catalytically Active Co−Nx Species Stabilized on Nitrogen‐doped Porous Carbon for Efficient Hydrogenation and Dehydrogenation of N‐heteroarenes. Issue 17 (2nd July 2020)

• Record Type: Journal Article
• Authors: Xu, Dan; Zhao, Hong; Dong, Zhengping; Ma, Jiantai
• Is Part Of: ChemCatChem. Volume 12:Issue 17(2020)
• Page Start: 4406
• Page End: 4415
• Publication Date: 2020-07-02
• Subjects: Nitrogen-doped carbon -- cobalt-nitrogen sites -- bifunctional catalyst -- oxidative dehydrogenation -- transfer hydrogenation; Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.202000826
• Languages: English
• ISSNs: 1867-3880

Abstract

Abstract: The development of bifunctional, highly active and stable non‐noble‐metal catalysts is important for synthetic chemistry. In this study, a highly dispersed Co catalyst stabilized on the mesoporous N‐doped carbon layers was prepared by adsorption and pyrolysis of cobalt complex on dendritic fibrous silica nanospheres (KCC‐1@Co−N−C−T). The characterizations of HAADF‐STEM, XRD and XPS together with the KSCN poisoning tests determine the absence of Co 0 or CoOx nanoparticles and suggest that the Co−Nx species are the active sites. The formation of Co−Nx species results from the properties of N‐rich cobalt‐phenanthroline complex and dendritic fibrous silica supports, increasing the original spatial distance between Co atoms and thus preventing them from aggregation. The KCC‐1@Co−N−C‐800 catalyst showed excellent activity and selectivity for the oxidative dehydrogenation (ODH) of saturated N‐heterocycles and base‐free catalytic transfer hydrogenation (CTH) of unsaturated N‐heterocycles. Abstract : N‐heteroarene (de) hydrogenations : A highly dispersed Co catalyst stabilized on the mesoporous N‐doped carbon layers was prepared by adsorption and pyrolysis of cobalt complex on dendritic fibrous silica nanospheres. The Co‐Nx species catalyst showed excellent catalytic activities for both oxidative dehydrogenation and catalytic transfer hydrogenation reactions. The turnover frequency (TOF) of KCC‐1@C−N−C‐800 could reach 3–24 times higher values than other reported transition‐metal‐based catalysts for hydrogenation reactions.