Enhanced UV Light–Driven Photocatalytic Degradation of Methylene Blue by Fe-Doped SnO2 Nanoparticles

In this work, a series of pure and doped SnO2 nanoparticles (SF0, SF5, and SF10 NPs) are successfully synthesized by the sol-gel method. The structural, optical, functional, morphological, and magnetic behaviors were distinguished by the XRD, UV, PL, FTIR, SEM with EDAX and HR-TEM techniques respectively. From the XRD analysis, the tetragonal SnO2 nanostructures were identified with an observed crystallite size from 7.4 to 15.2 nm. The UV-visible absorption spectra of SF0, SF5, and SF10 nanoparticles were observed around 331, 339, and 343 nm and their energy gap values were calculated to be 3.74, 3.65, and 3.61 eV. The PL emission peaks that appeared at 366 and 485 nm were attributed to the free of charge exciton electron-hole recombination and the surface defects of O2 vacancy in these SnO2 nanoparticles, respectively. The vibration properties of SF0, SF5 and SF10 nanoparticles were recognized using FTIR spectra. The strong Sn = O vibration modes observed at 1083 cm−1 was characterized to the external surface cation- oxygen (Sn and O) bonds. SEM images revealed that the indefinite and spongy cluster for both SF0 and SF5 and the agglomerated spherical-like morphologies of SF10 EDAX analyses confirmed the Sn, O, and Fe contents in all doped samples. The HR-TEM image of the SnO2 NPs contains with a d-spacing which corresponds to the interplaner distance of planes of SnO2. The photocatalytic performance of SF0, SF5, and SF10 nanoparticles were tested through the degradation of methylene blue (MB) dye in UV light irradiation, and the results reveal 85% degradation effectiveness of MB by SF10 over a period of 180 min.