Effect of N₂/Ar plasma treatment on the visible light photocatalytic activity of CuO/TiO₂

The effect of N₂/Ar dielectric barrier discharge plasma on the photocatalytic activity of CuO/TiO₂ under visible light irradiation was studied. The photocatalysts were characterized by X-ray diffraction, ultraviolet-visible spectrophotometry, transmission electron microscopy, X-ray photoelectron spectroscopy, and electron paramagnetic resonance spectroscopy. The plasma parameters including gas composition, treatment time, and plasma power were investigated. The activities of the plasma-treated photocatalysts were evaluated by the photodegradation of methyl orange under visible light illumination. The optimal operation conditions were N₂:Ar = 8:2, treatment time of 20 min, and a discharge current of 1.0 A. Simulated mercury-containing wastewater was treated by the photocatalysts.