This book consists of synthesis and characterization of ZnO and Mn-doped ZnO nanoparticles for photocatalyst process. The work contains synthesis (co- precipitation), Characterization (TEM, SEM, EDX, FTIR, XRD, BET, UV-visible NIR) and application of ZnO and Mn-doped ZnO nanoparticles. The application included photodegradation of m-, o- and p-cresol that was carried out under UV and visible irradiation at room temperature, atmospheric pressure, and different PH by batch photoreactors. The intermediates were identified by UPLC and mineralization was confirmed by TOC measurement. As a result,...