Synthesis of novel ZnO nanoparticles with exceptional crystalline and photocatalytic features toward recalcitrant pollutant: Fluorescein dye

ZnO is one of the most semiconductors used in vital photocatalytic applications as water splitting to produce H2 fuel and water treatment for the degradation of various water contaminants. In current work, ZnO nanoparticles were fabricated by a facile Template-free sol-gel method and characterized by TGA, XRD, FTIR, FESEM, TEM, EDX, DRS, XPS, and nitrogen adsorption-desorption isotherm. The optical property was investigated by photoluminescence (PL) spectra. As prepared ZnO nanoparticles showed strong UV emission at 398 nm, and three low-intensity bands cover most of the visible range, 450–600 nm, which attributed to the defects in ZnO, including oxygen-vacancy and interstitial Zn defects which reflects its high catalytic activity. The photocatalytic activity of the prepared ZnO nanoparticles was investigated toward the photodegradation of photostable Fluorescein dye (Flu); at pH 7, almost 100% of Fluorescein dye has been disappeared in 150 min. The photodegradation of dye obeys 1st-order kinetics. Besides, the influenceses of various factors like pH, dye concentration, and catalyst dose on the photodegradation were investigated. The reduction in TOC of dye displayed that not only did decolorization occur, but complete mineralization of Fluorescein dye also was achieved. Reusability study showed the catalyst is stable for four times.