Development of oxygen vacancies and surface defects in Mn-doped ZnO nanoflowers for enhancing visible light photocatalytic activity

Pure and Mn-doped ZnO nanoflowers were successfully synthesized by the hydrothermal technique. Doping of Mn into ZnO lattice exhibits formation of oxygen vacancies and surface modifications into ZnO lattice was investigated by XPS spectra and AFM analysis. During the photocatalytic performance, vacancies create the trap centers for photogenerated electrons hence the electron-hole recombination is effectively inhibited. These formed oxygen vacancies along with enhanced surface area are due to Mn doping, resulted in effective photodegradation of methylene blue solution under solar light irradiation. The degradation efficiency for methylene blue dye exceeds 82% after 120 min under solar light irradiation, also the catalytic performance of Mn-doped ZnO nanoflowers retains even after 4 cycles.