Cobalt Nanoparticles Embedded in N‐Doped Porous Carbon Derived from Bimetallic Zeolitic Imidazolate Frameworks for One‐Pot Selective Oxidative Depolymerization of Lignin

• Published in: ChemCatChem Vol. 11; no. 4; pp. 1264 - 1271
• Main Authors: Sun, Kangkang, Chen, Shujie, Zhang, Jiawei, Lu, Guo‐Ping, Cai, Chun
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 20.02.2019
• Subjects: Bimetallic zeolitic imidazolate frameworks; Bimetals; Carbon; Catalysis; Catalysts; Cobalt; Cobalt nanoparticles; Depolymerization; Electron transfer; Heterogeneous catalysis; Lignin; Magnetic fields; Metal-organic frameworks; Nanoparticles; Nitrogen; Oxidation depolymerization; Pressure; Pyrolysis; Substrates
• DOI: 10.1002/cctc.201801752
• ISSN: 1867-3880

Cobalt nanoparticles embedded in N‐doped porous carbon (Co@CN) were prepared by the pyrolysis of bimetallic zeolitic imidazolate frameworks (BMZIFs) based on ZIF‐8 and ZIF‐67. The catalyst shows excellent catalytic efficiency in one‐pot selective oxidative cleavage of different linkages like β‐O‐4, a‐O‐4 and β‐1 in organosolv lignin and lignin model compounds in the presence of oxygen (ambient pressure) under mild conditions (383 K). Compared with traditional supported catalyst, the catalyst gives a highly hollow structure, which favored the adsorption of substrates and oxygen. The uniform cobalt nanoparticles surrounded by N‐doped graphitic structures and the strong electron transfer from graphitic nitrogen to Co NPs make it hard to be oxidized prior to use and higher catalytic reactivity. Moreover, the catalyst can be easily recovered by magnetic force after the reaction, and reused after reduction for five times without an obvious change in yields. Selective oxidative dissociation of lignin: One‐pot Co@CN catalyzed selective oxidative dissociation of lignin and lignin model compounds with different linkages like β‐O‐4, α‐O‐4 and β‐1 under mild conditions without the assistance of any acid, base, ligand or noble metal has been reported.