In FGO/Ag-9 (pH = 9.51, without addition of NaOH) the intensity of the SPR peak is weak and broad, evidence of the slow and incom- plete reduction of silver ions. When the solution’s pH was in- creased by the addition of NaOH, the intensity of the peak increased and a shift in the kmax was observed, suggesting an accel- eration in the reaction rate and decreased particle size, as was also evident from the decreasing FWHM in the UV-visible spectrum with increasing pH from 9.51 to 11.40, i.e., the FWHM of FGO/ Ag-9, FGO/Ag-10 and FGO/Ag-11 were 113, 91.68 and 74.36, respectively. The sharp and low FWHM of FGO/Ag-11 suggests