Comparison of facile synthesized N doped, B doped and undoped ZnO for the photocatalytic removal of Rhodamine B

Abstract In a solid phase, the undoped ZnO, B n -ZnO and N n -ZnO (1–5 wt%) nanoparticles were prepared by an energy saving, facile, novel and effective mechanochemical method with subsequent calcination. For the first time, their photocatalytic activities were tested for the degradation of Rhodamine B dye. To optimize the doping effect, different rates of these metal oxides were synthesized and performed for the decomposition. The structural and morphological evolution of the produced porous zinc oxides were then characterized by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and scanning electron microscope (SEM). Additionally, UV–vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL) and Brunauer–Emmett–Teller (BET) analysis were performed. The XRD patterns of samples were attributed to typical wurtzite structure of ZnO with the smallest crystallite size about 9 nm. In the SEM images of the undoped and N doped ZnO samples, “rod like” hexagonal crystals are predominant form for the agglomeration of particles, whereas cubic structure dominates the SEM image of B doped ZnO. The Kubelka-Munk transformed DRS spectra of the samples indicated that the optical band gap energies are in the range of 3.38–3.48 eV. Photocatalytic activities were performed with the use of 0.1 mg of powder catalyst for 100 mL of aqueous dye solution under simulated solar light irradiation at pH 7 and 10. Among the photocatalysts, N 4% -ZnO was found to be the most efficient on the decomposition of Rhodamine B dye owing to its modified porous nanostructure, large surface area and optical properties.