Catalysts (May 2024)
Highly Tuning of Sunlight-Photocatalytic Properties of SnO<sub>2</sub> Nanocatalysts: Function of Gd/Fe Dopants
Abstract
Gd/Fe-SnO2 nanopowders as novel photocatalysts for the active removal of Rose Bengal dye and methyl parathion pesticide were synthesized with a low-cost coprecipitation route. The X-ray diffraction analysis of SnO2, Sn0.96Gd0.02Fe0.02O2 and Sn0.94Gd0.02Fe0.04O2 nanopowders proved the formation of a tetragonal phase of tin oxide with average crystallite sizes in the range of 13–18 nm. The Fourier transform infrared (FTIR) spectra of all samples displayed the characteristic absorption bands of SnO2. The nanopowder of the pure SnO2 sample, as seen in its transmission electron microscope (TEM) image, contains spherical-like particles of variable sizes. The TEM images of the Sn0.96Gd0.02Fe0.02O2 and Sn0.94Gd0.02Fe0.04O2 powders revealed the synthesis of fine spherical nanoparticles. Based on the TEM images, the average particle size of the pure, (Gd, 2 wt% Fe) and (Gd, 4 wt% Fe) codoped SnO2 nanopowders was estimated to be 14, 10 and 12 nm, respectively. After the addition of (Gd, 2 wt% Fe) and (Gd, 4 wt% Fe) to the SnO2 structure, the band gap energy of SnO2 was reduced from 3.4 eV to 2.88 and 2.82 eV, respectively. Significantly, the Sn0.96Gd0.02Fe0.02O2 nanocatalyst exhibited a high removal efficiency of 98 and 96% for Rose Bengal dye and methyl parathion pesticide after activation by sunlight for 35 and 48 min, respectively. Furthermore, this catalyst has shown perfect mineralization as well as high stability properties for the treatment of Rose Bengal dye and methyl parathion pesticide. These results suggest the suitability of the Sn0.96Gd0.02Fe0.02O2 nanocatalyst for the treatment of agriculture and industrial effluent under sunlight light energy.
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