Enhanced Photocatalytic Degradation of Organic Dyes via Defect-Rich TiO Prepared by Dielectric Barrier Discharge Plasma.

The dye wastewater produced in the printing and dyeing industry causes serious harm to the natural environment. TiO usually shows photocatalytic degradation of dye under the irradiation ultravilet light rather than visible light. In this work, a large number of oxygen vacancies and Ti defects were generated on the surface of the TiO nanoparticles via Ar plasma. Compared with pristine TiO nanoparticles, the as-obtained Ar plasma-treated TiO (Ar-TiO) nanoparticles make the energy band gap reduce from 3.21 eV to 3.17 eV and exhibit enhanced photocatalytic degradation of organic dyes. The Ar-TiO obtained exhibited excellent degradation properties of methyl orange (MO); the degradation rate under sunlight irradiation was 99.6% in 30 min, and the photocatalytic performance was about twice that of the original TiO nanoparticles (49%). The degradation rate under visible light (λ > 400 nm) irradiation was 89% in 150 min, and the photocatalytic performance of the Ar-TiO was approaching ~4 times higher than that of the original TiO nanoparticles (23%). Ar-TiO also showed good degradation performance in degrading rhodamine B (Rho B) and methylene blue (MB). We believe that this plasma strategy provides a new method for improving the photocatalytic activity of other metal oxides.