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. , ...Daha Fazla

CHEMISTRYSELECT, cilt.5, ss.9143-9152, 2020 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 5 Konu: 29
  • Basım Tarihi: 2020
  • Doi Numarası: 10.1002/slct.202002327
  • Dergi Adı: CHEMISTRYSELECT
  • Sayfa Sayıları: ss.9143-9152

Özet

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.

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.