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Fabrication of novel ternary Au/CeO2@g-C3N4 nanocomposite: kinetics and mechanism investigation of 4-nitrophenol reduction, and benzyl alcohol oxidation

Kohantorabi, M ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1007/s00339-018-1858-0
  3. Publisher: Springer Verlag , 2018
  4. Abstract:
  5. Abstract: Au nanoparticles supported on cerium oxide/graphitic carbon nitride (CeO2@g-C3N4) was synthesized and used as heterogeneous catalyst in redox reaction. The catalyst was characterized by different techniques such as FT-IR, XRD, FE-SEM, EDS, TEM, BET, TGA, and ICP. The as-prepared ternary nanocomposite was used as an effective catalyst for the reduction of toxic 4-nitrophenol to useful 4-aminophenol by NaBH4. The rate constant value of reduction reaction reached up to 0.106 s−1 by Au/CeO2@g-C3N4, which was 3.8, and 8.8 times higher than that of Au@CeO2 (0.028 s−1), and Au@g-C3N4 (0.012 s−1) nanocomposites, respectively. The superior catalytic performance of as-prepared catalyst in 4-NP reduction can be attributed to synergistic effect between Au nanoparticles and CeO2@g-C3N4 support, and efficient electron transfer. The reduction reaction was carried out at different temperatures, and the energy of activation (Ea), and thermodynamic parameters including, activation of entropy (Δ S≠), enthalpy (Δ H≠), and Gibbs free energy (Δ G≠) were determined. Additionally, the mechanism of reaction was studied in details, and equilibrium constants of 4-NP (K4-NP), and BH4- (KBH4-) were calculated using Langmuir–Hinshelwood model. Furthermore, this nanocomposite exhibited excellent catalytic activity in oxidation of benzyl alcohol by molecular oxygen as a green oxidant. This study revealed that the ternary Au/CeO2@g-C3N4 nanocomposite is an attractive candidate for catalytic applications. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature
  6. Keywords:
  7. Activation energy ; Catalyst activity ; Catalytic oxidation ; Cerium oxide ; Equilibrium constants ; Free energy ; Gibbs free energy ; Gold ; Molecular oxygen ; Nanocomposites ; Nanoparticles ; Rate constants ; Redox reactions ; Sodium Borohydride ; Synthesis (chemical) ; 4-Nitrophenol reductions ; Benzyl alcohol oxidation ; Catalytic applications ; Catalytic performance ; Heterogeneous catalyst ; Kinetics and mechanism ; Ternary nanocomposites ; Thermodynamic parameter ; Gold nanoparticles
  8. Source: Applied Physics A: Materials Science and Processing ; Volume 124, Issue 6 , 2018 ; 09478396 (ISSN)
  9. URL: https://link.springer.com/article/10.1007/s00339-018-1858-0