Green Synthesis of Luminescent Gold-Zinc Oxide Nanocomposites: Cell Imaging and Visible Light–Induced Dye Degradation

Abstract

Green synthesis of gold-zinc oxide (Au-ZnO) nanocomposite was successfully attempted under organic solvent–free conditions at room temperature. Prolonged stirring of the reaction mixture introduced crystallinity in the ZnO phase of Au-ZnO nanocomposites. Luminescence properties were observed in these crystalline Au-ZnO nanocomposites due to in situ embedding of gold nanoparticles (AuNP) of 5–6 nm diameter on the surface. This efficient strategy involved the reduction of Au(III) by Zn(0) powder in aqueous medium, where sodium citrate (NaCt) was the stabilizing agent. Reaction time and variation of reagent concentrations were investigated to control the Au:Zn ratio within the nanocomposites. The reaction with the least amount of NaCt for a long duration resulted in Au-ZnO/Zn(OH)2 nanocomposite. X-ray photoelectron spectroscopy (XPS) confirmed the formation of Zn(OH)2 and ZnO in the same nanocomposite. These nanocomposites were reconnoitered as bioimaging materials in human cells and applied for visible light–induced photodegradation of rhodamine-B dye.

Solar light induced photocatalytic degradation of tetracycline in the presence of ZnO/NiFe2O4/Co3O4 as a new and highly efficient magnetically separable photocatalyst

“…As presented in Figure 4B , the high-resolution X-ray photoelectron spectroscopy (XPS) spectrum of Zn 2p is resolved into four peaks located at 1019.8 and 1021.3 eV for Zn 2p 3/2 , and 1042.9 and 1044.2 eV for Zn 2p 1/2 . These peaks are related to the zinc lattice in ZnO ( Srivastava et al, 2018 ; Bharti et al, 2021 ; Kohantorabi et al, 2021 ). In addition, the observed spin-orbital split of Zn (between Zn 2p 1/2 and Zn 2p 3/2 ) is about 23 eV, which is in agreement with the reference value of ZnO ( Liu et al, 2019 ; Kohantorabi et al, 2021 ).…”

Three-Dimensional Assemblages of Metal Silicate for Catalytic CO2 Conversion to Methanol and Adsorptive Pollutant Removal

“…The O 1s peak of ZnSiO can be deconvoluted into three peaks: 532.0, 532.4, and 532.7 eV, which are assigned to Zn–O–Si, O–H, and Si–O–Si bonds, respectively, reminiscent of the published values for zinc silicate nanosheets. , Since there are two main deconvoluted O 1s peaks, without a clear majority in either silica form (i.e., SiO 2 ) or the metal oxide (i.e., ZnO), it is suggestive and as expected for a zinc silicate material. The small peak located at about 532.4 eV could have resulted from the O–H bonds, possibly due to a small amount of hydroxyl group (e.g., Zn–O–H) , present on the surface of the ZnSiO substrate.…”

“…43,44 Since there are two main deconvoluted O 1s peaks, without a clear majority in either silica form (i.e., SiO 2 ) or the metal oxide (i.e., ZnO), it is suggestive and as expected for a zinc silicate material. The small peak located at about 532.4 eV could have resulted from the O−H bonds, possibly due to a small amount of hydroxyl group (e.g., Zn− O−H) 45,46 present on the surface of the ZnSiO substrate.…”

Origin of luminescence properties and synthetic methods for gold- and bimetallic gold-based nanomaterials

“…19A) in aqueous medium from the growth of AuNPs as seeds, sodium citrate as the stabilizing agent and Zn powder as the reducing agent for Au 3+ ions added to the growth solution. 199 The broad emission (Fig. 19B) is due to the presence of ZnO and freshly generated 5–6 nm AuNPs on the surface of the nanocomposite.…”