A New Approach to Synthesis of Highly Dispersed Gold Nanoparticles via Glucose Oxidase-Immobilized Hydrogel and Usage in The Reduction of 4-Nitrophenol


ÖZAY H., Tarimeri N., Güngör Z., DEMİRBAKAN B., ÖZCAN B., SEZGİNTÜRK M. K. , ...More

CHEMISTRYSELECT, vol.5, no.29, pp.9143-9152, 2020 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 5 Issue: 29
  • Publication Date: 2020
  • Doi Number: 10.1002/slct.202002327
  • Journal Name: CHEMISTRYSELECT
  • Journal Indexes: Science Citation Index Expanded, Scopus, Academic Search Premier
  • Page Numbers: pp.9143-9152
  • Keywords: Catalytic reduction, Enzyme, Glucose Oxidase, Gold, Hydrogel, 4-Nitrophenol, REDUCED GRAPHENE OXIDE, CATALYTIC-REDUCTION, NICKEL NANOPARTICLES, ZINC PHTHALOCYANINE, SELECTIVE REDUCTION, EFFICIENT CATALYST, ACTIVE CATALYSTS, FACILE SYNTHESIS, POLYMER, SILVER

Abstract

In this study, for the first time in the literature, synthesis of Au(0) nanoparticles supported by a crosslinked gel structure was performed via enzyme-mediated reduction of Au(III) ions without using any chemical reductant. In our newly-developed method, glucose oxidase enzymes immobilized in the crosslinked gelatine structure ensured simultaneous reduction of the Au(III) ions diffused within the gel to Au(0). The Au@Gel obtained was structurally characterised with TEM (Transmission electron microscopy), EDX (Energy dispersive X-ray analysis) elemental mapping, XPS (X-Ray photoelectron spectroscopy) and XRD (X-Ray Diffraction) analyses. The catalytic activity of Au(0) particles with nearly 8 nm size in the Au@Gel was investigated for the reduction of 4-nitrophenol (4-NP) as a model compound in the presence of NaBH4 as reducing agent. The activation parameters for the reduction reaction of 4-nitrophenol in the presence of Au@Gel catalyst were determined as Ea= 30.16 kJmol, ΔH#= 27.52 kJmol and ΔS#= −197.45 JmolK. The Au@Gel catalyst system, with good catalytic activity, simultaneously has nearly perfect reusability.

In this study, for the first time in the literature, synthesis of Au(0) nanoparticles supported by a crosslinked gel structure was performed via enzyme-mediated reduction of Au(III) ions without using any chemical reductant. In our newly-developed method, glucose oxidase enzymes immobilized in the crosslinked gelatine structure ensured simultaneous reduction of the Au(III) ions diffused within the gel to Au(0). The Au@Gel obtained was structurally characterised with TEM (Transmission electron microscopy), EDX (Energy dispersive X-ray analysis) elemental mapping, XPS (X-Ray photoelectron spectroscopy) and XRD (X-Ray Diffraction) analyses. The catalytic activity of Au(0) particles with nearly 8 nm size in the Au@Gel was investigated for the reduction of 4-nitrophenol (4-NP) as a model compound in the presence of NaBH(4)as reducing agent. The activation parameters for the reduction reaction of 4-nitrophenol in the presence of Au@Gel catalyst were determined as E-a= 30.16 kJmol(-), Delta H= 27.52 kJmol(-)and Delta S= -197.45 Jmol(-)K(-). The Au@Gel catalyst system, with good catalytic activity, simultaneously has nearly perfect reusability.