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

Abstract

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.

Efficient Removal of Methylene Blue and Ciprofloxacin from Aqueous Solution Using Flower-like, Nanostructured ZnO Coating under UV Irradiation

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“…The lattice parameters a, and c for wurtzite ZnS nanowires were calculated using the following formula 23 , 24 . …”

Photoluminescent and photocatalytic properties of Cu2+ and Mg2+‐doped ZnO nanoparticles obtained by a facile sonochemical method

“…When there is a decrease in lattice defects, the higher degree of crystallinity promotes less recombination between photogenerated electrons and holes. 10,45,47 The band gap of samples was obtained through the diffuse reflectance spectroscopy in the ultraviolet visible region and the obtained data were converted for absorption. The values were calculated by extrapolating the x-axis from the straight line from absorbance curves, as shown in Figure 2.…”

“…The zinc oxide (ZnO) inherent characteristics such as wide band gap (3.3 eV), high excitation binding energy (60 meV), 6,7 abundance in nature, 8 low cost, 9,10 absence of toxicity, and chemical stability 11,12 . This semiconductor can be obtained by several methods 13,14 such as sonochemical, 15,16 hydrothermal, 17,18 coprecipitation, 19–21 and spray pyrolysis 22,23 .…”