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Magnetic Halloysite/Fe3O4/AuNPs Nanocomposite as a Recyclable Efficient Catalyst for Hydrogenation of Congo Red and 4-Nitrophenol

[ Vol. 5 , Issue. 2 ]

Author(s):

Wenkai Dong, Wenbo Wang*, Yuru Kang and Aiqin Wang*   Pages 144 - 154 ( 11 )

Abstract:


Objective: A supermagnetic halloysite/Fe3O4/Au nanoparticles (HNT/Fe3O4/AuNPs) nanocomposite was fabricated by a facile non-covalent self-assembly approach and used as a recyclable catalyst for the hydrogenation of Congo Red (CR) and 4-nitrophenol (4-NP).

Method: The AuNPs were successfully decorated onto the HNT/Fe3O4 carrier using natural polymer chitosan (CTS) as a “bridge”. The formation of the nanocomposite and the uniform distribution of AuNPs on the HNT/Fe3O4 carrier were confirmed by UV-vis, FTIR, XRD, TGA and TEM analyses. Due to the successful loading of small-size AuNPs, the resulting HNT/Fe3O4/AuNPs nanocomposite showed very good catalytic activity. At a low catalyst concentration (0.25-0.5 g/L), the nanocomposite can catalyze the rapid decoloration of the 25 mg/L CR solution within 4 min and rapid reduction of 4- nitrophenol (4-NP) into 4-aminophenol (4-AP) within 5 min through a catalytic hydrogenation reaction in the presence of sodium borohydride.

Result: In the catalysis reaction process, the AuNPs acted as the “courier station” to promote the electron transfer and thus accelerated the reaction process. After reusing for 8 catalysis cycles, the catalytic activity of the nanocomposite still remained good. In addition, the nanocomposite showed the maximum magnetization rate of 33.6 emu/g, which made it easy to separate it from the solution by a magnet for recycling and reusing.

Conclusion: In a word, the nanocomposite has potential to be used as a high-efficient catalyst for the decoloration of dye and conversion of 4-NP by a hydrogenation reaction.

Keywords:

Halloysite, magnetic nanocomposite, dye, 4-nitrophenol, congo red, catalysis.

Affiliation:

Key Laboratory of Clay Mineral Applied Research of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, Key Laboratory of Clay Mineral Applied Research of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, Key Laboratory of Clay Mineral Applied Research of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, Key Laboratory of Clay Mineral Applied Research of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000

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