Carbon 200 mesh copper grid

UV/vis spectrophotometry analysis was performed using a Cary 60 UV/vis spectrophotometer (Agilent). For transmission electron microscopy (TEM) analysis, 5 μL of nanoparticle solution (1 mg/mL) were drop cast onto a carbon 200-mesh copper grid (Ted Pella) and the grids were covered and air-dried overnight, prior to imaging. TEM imaging was performed with a JEOL 2100 field thermionic emission TEM equipped with a silicon-drifted detector-based energy dispersive x-ray spectroscopy (EDS) system. ImageJ software was utilized to determine nanoparticle yields. Selected area electron diffraction (SAED) patterns were obtained using the field-limiting aperture, and fast Fourier transforms (FFT) were obtained in high-resolution mode. Determination of the 3D structure of the nanoparticles was obtained using tilt tomography and a tilt angle of 30°. DigitalMicrograph (Gatan) was used to analyze diffraction patterns, for FFT, to measure d-spacing, and to determine particle sizes.

To synthesize AgNPs, 4 mL of each DI extract was added to 16 mL of 1 mM silver nitrate solution. The mixture was allowed to react at room temperature for 24 h. AgNP formation was monitored by measuring the UV–Vis spectrum of each reaction solution using a SpectraMax i3X microplate reader (Molecular Devices, Sunnyvale, CA, USA) from 300–700 nm. The formed AgNPs were collected by centrifugation at 3000× g for 20 min and were washed with DW using a 10 kDa weight cut-off filter (Amicon Ultra-15 MWCO, Merck Millipore, Burlington, MA, USA). The obtained AgNPs were resuspended in 4 mL of DW. The surface charge and size distribution of the synthesized AgNPs were measured by DLS using a Zetasizer Nano ZS90 instrument (Malvern Instruments, Malvern, Worcestershire, UK). The structure of the synthesized AgNPs was determined by high-resolution powder XRD using an Empyrean instrument (PANalytical, Almelo, The Netherlands) in the 10°–80° 2θ range with Cu Kα radiation. The AgNP morphology was determined by TEM using an H-7650 electron microscope (Hitachi, Tokyo, Japan). Each sample was drop-casted onto a carbon 200 mesh copper grid (Ted Pella, Redding, CA, USA) and dried in a vacuum desiccator overnight.

The morphology of the prepared sol-gel-coated AAO membrane was investigated by SEM (JSM-6710F, JEOL, Tokyo, Japan). After post-gelation, the samples were dried overnight in a vacuum chamber to eliminate water from the sol-gel matrix and thereafter transferred to the carbon tape on the SEM specimen stub. Subsequently, the prepared samples were coated with platinum to reduce the charging effects during SEM analysis. The structure of sol-gel nanocolumn defined by the AAO membrane was also observed by TEM (H-7650, Hitachi, Japan) after dissolving the AAO template using a 1 M NaOH solution for 3 h at 30 °C. The white precipitate upon completing the AAO dissolution reaction in the sample tube was collected by mild centrifugation with a washing step using filtered distilled water. Finally, the acquired sol-gel nanocolumn was dispersed by mild pipetting and drop-casted onto a carbon 200 mesh copper grid (Ted Pella, Redding, CA, USA). The prepared samples were dried overnight in a vacuum desiccator and observed by TEM under optimized conditions.