Fig. 1 X-ray diffraction pattern of Ag–ZnO nanocomposites showing reflections of metallic

Fig. 2 SEM images of Ag–ZnO with 15 mm a, 5 mm b working distance (accelerating voltage 20 kV, current 20 μA)

Fig. 3 SEM–EDS spectrum of the Ag–ZnO nanocomposite

Fig. 4 UV–Vis reflectance spectra of Ag–ZnO

Fig. 5 PL spectra of Ag–ZnO in acetone when excited at 350 nm

Fig. 6 PL spectra of Ag–ZnO in acetone when excited at 450 nm

Fig. 7 Typical plot for Langmuir isotherm a, Freundlich isotherm b in the presence of Ag/ZnO

Fig. 8 Typical plot for: a change in the absorption spectrum of methyl violet 6B by ZnO, b change in the absorption spectrum of methyl violet 6B by Ag/ZnO, c comparison of change in absorbance (absorbance after irradiation, A and absorbance before irradiation, A0) vs. irradiation time for methyl violet 6B by ZnO and Ag/ZnO, d comparison of degradation percent vs. irradiation time for methyl violet 6B in the presence and absence of ZnO, e comparison of degradation percent vs. irradiation time for methyl violet 6B and methyl orange in the presence and absence of Ag/ZnO, f comparison of degradation percent vs. irradiation time at different pH values in the presence of Ag/ZnO nanomaterials (0.5 g/L) containing methyl violet 6B

Fig. 9 Natural logarithms of absorbance of methyl violet 6B plotted as a function of UV-irradiation time

Fig. 10 Percent of decolourization vs. irradiation time for industrial effluent

Fig. 11 Comparison of percentage degradation of methyl violet 6B under different advance oxidation processes (experimental conditions: dye concentration is 5 ppm; H2O2 concentration is 5 mmol; T = 303 K; V = 100 mL; irradiation time is 2 h; Photocatalyst: Ag–ZnO = 50 mg)

Fig. 12 Effect of Ag/ZnO reuse on photocatalytic decolorization (after 210 min irradiation) (Run 1 fresh Ag/ZnO; Run 2 first reuse; Run 3 second reuse; Run 4 third reuse)