Visible light photocatalytic activity of Fe3+-doped ZnO nanoparticle prepared via sol–gel technique

The optical properties of a ZnO photocatalyst were enhanced with various dopant concentrations of Fe3+. Doped ZnO nanoparticles were synthesized via a sol–gel method without the use of capping agents or surfactants and was then characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and ultraviolet–visible (UV–Vis) spectroscopy. The results showed that ZnO has a wurtzite, hexagonal structure and that the Fe3+ ions were well incorporated into the ZnO crystal lattice. As the Fe3+ concentration increased from 0.25 wt.% to 1 wt.%, the crystal size decreased in comparison with the undoped ZnO. The spectral absorption shifts of the visible light region (red shift) and the band gap decreases for each Fe–ZnO sample were investigated. The photocatalytic activities of the ZnO and Fe–ZnO samples were evaluated based on the degradation of 2-chlorophenol in aqueous solution under solar radiation. The samples with a small concentration of Fe3+ ions showed enhanced photocatalytic activity with an optimal maximum performance at 0.5 wt.%. The results indicated that toxicity removal of 2-chlorophenol at same line of degradation efficiency. Small crystallite size and low band gap were attributed to high activities of Fe–ZnO samples under various concentrations of Fe3+ ions compared to undoped ZnO.

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► Fe3+ doped ZnO nanoparticle was prepared by the sol gel method without capping agents.
► The strongly absorption in visible light (red shift) of Fe3+ doped ZnO samples was observed.
► The activity of the Fe3+ doped ZnO was evaluated to degradation of 2-CP under sunlight.
► The results showed that toxicity removal of 2-CP at same line of degradation efficiency.