In situ-formed cobalt embedded into N-doped carbon as highly efficient and selective catalysts for the hydrogenation of halogenated nitrobenzenes under mild conditions

• Published in: Applied catalysis. A, General General, 2020-02, Vol.592, p.117434, Article 117434
• Main Authors: Cao, Yueling, Liu, Kangkai, Wu, Chen, Zhang, Hepeng, Zhang, Qiuyu
• Format: Article
• Language: English
• Subjects: Carbon; Catalysts; Catalytic activity; Catalytic converters; Cobalt; Halogenated nitrobenzenes; Halogenation; Hydrogen storage; Hydrogenation; Industrial applications; Melamine; N-doped carbon supported Co; Nitrobenzene; Noble metals; One-pot pyrolysis; Pyrolysis; Selective hydrogenation; Selectivity; Substrates; Tannic acid
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2020.117434

[Display omitted] •Cobalt embedded into N-doped carbon was fabricated through one-pot pyrolysis of a mixture of Co (Ⅱ)-tannic acid coordination polymers and melamine.•The dosage of tannin acid in catalyst preparation process was a crucial factor in affecting the dispersion and exposure degree of Co nanoparticles.•The Co@CN catalyst exhibited an excellent catalytic performance for the liquid-phase hydrogenation of halogenated nitrobenzenes under 1 MPa H2 at 60 °C. Inhibiting the dehalogenation is the main challenge when halogenated nitrobenzenes are hydrogenated using H2 as hydrogen source by heterogeneous catalysis. Herein, the earth-abundant cobalt embedded into N-doped carbon (Co@CN) catalysts were fabricated via one-pot pyrolysis of tannic acid, Co(NO3)2·6H2O and melamine, which can function as a highly efficient non-noble-metal-based heterogeneous catalyst for selective hydrogenation of halogenated nitrobenzenes. Chloroanilines, bromoanilines, and iodoanilines, including all regioisomers, could be obtained with excellent selectivity (typically >99 %) at 60 °C under 1 MPa H2, at almost complete conversion of the substrates. Additionally, Co@CN demonstrated excellent catalytic stability and could be reused at least five times without obvious loss of catalytic activity and selectivity. Therefore, the Co@CN catalyst exhibits vast potential for future industrial application in the selective hydrogenation of halogenated nitrobenzenes.