Conformal coating of Co/N-doped carbon layers into mesoporous silica for highly efficient catalytic dehydrogenation–hydrogenation tandem reactions

Zhujun Zhang, Xiangru Wei, Yan Yao, Zhi Chen, Aijian Zhang, Wei Li, Winston Duo Wu, Zhangxiong Wu, Xiao Dong Chen, Dongyuan Zhao

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28 Citations (Scopus)

Abstract

To maximize the utilizing efficiency of cobalt (Co) and optimize its catalytic activity and stability, engineering of size and interfacial chemical properties, as well as controllable support are of ultimate importance. Here, the concept of coating uniform thin Co/N-doped carbon layers into the mesopore surfaces of mesoporous silica is proposed for heterogeneous aqueous catalysis. To approach the target, a one-step solvent-free melting-assisted coating process, i.e., heating a mixture of a cobalt salt, an amino acid (AA), and a mesoporous silica, is developed for the synthesis of mesoporous composites with thin Co/N-doped carbon layers uniformly coated within mesoporous silica, high surface areas (250–630 m2 g−1), ordered mesopores (7.0–8.4 nm), and high water dispersibility. The strong silica/AA adhesive interactions and AA cohesive interactions direct the uniform coating process. The metal/N coordinating, carbon anchoring, and mesopore confining lead to the formation of tiny Co nanoclusters. The carbon intercalation and N coordination optimize the interfacial properties of Co for catalysis. The optimized catalyst exhibits excellent catalytic performance for tandem hydrogenation of nitrobenzene and dehydrogenation of NaBH4 with well-matched reaction kinetics, 100% conversion and selectivity, high turnover frequencies, up to ≈6.06 molnitrobenzene molCo −1 min−1, the highest over transition-metal catalysts, and excellent stability and magnetic separability.

Original languageEnglish
Article number1702243
Number of pages8
JournalSmall
Volume13
Issue number42
DOIs
Publication statusPublished - 13 Nov 2017
Externally publishedYes

Keywords

  • cobalt catalysts
  • conformal coating
  • mesoporous materials
  • nitrogen-doped carbon
  • tandem dehydrogenation/hydrogenation

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