Why do I have extra peaks in the XRD pattern of ZnO nanoparticles?

I have prepared ZnO nanoparticles by biological method (with bacterial supernatant and extract). unfortunately, the XRD showed some extra peaks at 8.64, 11.9, 14.96, 17.28, 21.36, 24.7, 25.78,...

15 November 2021 299 17 View