D8 advance

The chemical compositions were determined using an electron probe micro-analyzer (EPMA) (S-4800, Hitachi, Japan) with an accuracy of >97%.
The structural analysis of the powders was made by powder X-ray diffractometer (D8 Advance) operating at 50 kV and 40 mA at Cu Kα radiation (λ = 0.15406 nm) in the 2θ range from 10° to 110° with a step size of 0.02°, and a X'Pert Pro, PANalytical code was used to do the Rietveld refinement of the XRD patterns with a step size of 0.01° using the same operating voltage and current. The lattice constants a and c were directly obtained from the refinement of the XRD patterns using Jade software (Highscore (plus) Software version 4.0 by PANalytical B.V; Almelo, The Netherlands)^{32 (link)} with an error less than 10%.
Differential Scanning calorimeter (DSC) and thermogravimetry (TG) were conducted in a Netzch STA 449 F3 Jupiter equipped with a TASC414/4 controller. The instrument was calibrated from a standard list. The sample of the powder (x = 0) was loaded into an open alumina crucible. The measurement was performed after the samples were heated up to ∼850 K with a heating rate of 5 K min⁻¹ in Ar atmosphere.

The average diameter of the spheres, expressed as mean ± standard deviation, was obtained from the photographs taken by random sampling of approximately 50 individual particles to minimize selection bias. X-ray diffraction (XRD, D8 Advance, PANalytical X’PERT PRO) patterns were obtained at room temperature using Cu K-α radiation (λ=1.5406 Å) with a range of 2θ=20° to 80°, and a scanning rate of 0.05 s⁻¹. The FTIR spectra were recorded with a Spectrum RXI FTIR Spectrometer, using KBr pellets, in the range of 400 to 4,000 cm⁻¹, with a resolution of 4 cm⁻¹. The micromorphology of the silver nanoparticles–chitosan composite spheres was analyzed using a SEM (S-2700, Hitachi Ltd., Tolyo, Japan) equipped with an energy dispersive spectrometer. The characterization of the silver nanoparticles was carried out using TEM (FEI Tecnai G² 20 S-Twin) and a UV-Vis absorbance spectrophotometer (Thermo Scientific Spectrascan UV 2700). The silver nanoparticles solution was prepared by adding 20 μL CH₃COOH solution and 1 mL dd-H₂O to ten silver nanoparticles–chitosan composite spheres, and then vortexing for 3–5 minutes. The silver nanoparticles–chitosan solution was dropped to grid by a micropipette for TEM analysis report.