Facile preparation of Ti3+ self-doped TiO2 nanoparticles and their dramatic visible photocatalytic activity for the fast treatment of highly concentrated Cr(vi) effluent

Abstract

In the present work, Ti³⁺ self-doped TiO₂ nanoparticles were prepared in a simple one-pot solvothermal process. Meanwhile, the photocatalytic activity of the as-prepared TiO₂ nanoparticles was explored under visible light irradiation for the treatment of effluent containing Cr(VI). Finally, the photocatalytic mechanism was discussed. The results show that the Ti³⁺ self-doped TiO₂ nanoparticles obtained are an efficient visible photocatalyst for the reduction of Cr(VI). When the concentration of Cr(VI) is 10 mg L⁻¹, about 95% of Cr(VI) can be removed within 1 min. More interestingly, the aforementioned TiO₂ nanoparticles are a promising candidate with remarkable visible photocatalytic activity for the fast treatment of highly concentrated Cr(VI) effluent. When the concentration of Cr(VI) is 34 mg L⁻¹, the reduction ratio of Cr(VI) is approximately 95% after 12 min of visible irradiation. Even if the concentration of Cr(VI) is very high (104 mg L⁻¹), the reduction ratio of Cr(VI) is still up to 94% after 5 h of irradiation. Our work provides a new strategy for designing an efficient visible photocatalyst which is suitable for the rapid removal of highly concentrated Cr(VI) for environmental therapy.