Photoredox degradation of different water pollutants (MO, RhB, MB, and Cr(VI)) using Fe–N–S-tri-doped TiO2 nanophotocatalyst prepared by novel chemical method

• TiO2 was synthesized through simple one-step hydrothermal method.
• Photocatalytic activity for degradation of organic dyes and Cr(VI) are investigated.
• The synergistic effect is shown in coexistence of MB and Cr(VI).

Fe–N–S-tri-doped TiO2 (FeNS-TiO2) was synthesized by a simple one-step hydrothermal method. The as-synthesized samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of as-synthesized samples were tested by the oxidation of methyl orange (MO), rhodamine B (RhB), methylene blue (MB) and the reduction of aqueous Cr(VI) under visible-light (λ > 420 nm) irradiation, and compared with N-dope P25 (N-P25) and the undoped TiO2. Besides, the effects of the coexistence of MO, RhB, and MB on FeNS-TiO2-mediated photocatalytic reduction of aqueous Cr(VI) were also studied. The results indicated FeNS-TiO2 displayed higher visible-light-activated photocatalytic activity than N-P25 and the undoped TiO2. Otherwise, FeNS-TiO2 showed the coexistence of MB enhanced the photocatalytic reduction of Cr(VI), whereas the coexistence of MO and RhB retarded the photocatalytic reduction of Cr(VI) over FeNS-TiO2. Moreover, a possible photocatalytic mechanism is discussed.

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