In this study, silver, zinc and copper nanoparticles, AgNPs, ZnNPs and CuNPs, were tested on photodegradation using phenol as a model contaminant. The nanoparticles were phytosynthesized from an aqueous extract of Eichhornia crassipes leaves, and were characterized by UV-visible spectroscopy, EDS (Dispersive Energy X-ray Spectroscopy), SEM (Scanning Electron Microscopy), and TEM (Transmission Electron Microscopy). The AgNPs, ZnNPs and CuNPs showed a characteristic plasmon determined by UV-Vis; in the case of the EDS analyses Ag, Zn and Cu were detected as the main components. The detected composition by TEM corresponded to a metallic oxide for the three nanoparticles. Finally, for the photocatalytic performance on the phenol degradation under UV radiation, they showed about 50%, 52% and 34% with a 10 mg/L phenol solution that was achieved within 200 min using AgNPs, ZnNPs and CuNPs, respectively.