Photocatalytic oxidation of gas-phase Hg0 by CuO/TiO2.

A simplified approach for the fabrication of CuO/TiO 2 was demonstrated. In this study, low cost CuO/TiO 2 photocatalysts (CuO loading 0–15 wt.%) were prepared, characterized and evaluated for gas-phase Hg 0 oxidation. The obtained CuO/TiO 2 photocatalysts were used to remove gaseous elemental mercury under UV light and visible light (both xenon lamp and LED), respectively, and the optimum doping levels of CuO and optimum illumination conditions were determined. The results showed that the CuO/TiO 2 photocatalysts were highly efficient in oxidizing Hg 0 , reaching above 70% in all cases under UV light, peaking at 57.8% with 1.25 wt.% CuO under visible light and peaking at about 60% with 1.25 wt.% CuO under LED light. We have proposed that the probable mechanism by which CuO/TiO 2 photocatalysts removes gaseous elemental mercury is two-fold: the CuO not only prevents electrons and holes from recombining, but also narrows the band gap of TiO 2 . [ABSTRACT FROM AUTHOR]