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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]

[Display omitted] • The different morphologies of BiOI and Bi modified Bi 4 O 5 I 2 catalysts were successfully synthesized by three methods. • The synergistic effect of oxygen vacancies and built-in electric field promotes the separation of photogenerated electron-holes. • The 3D Bi/Bi 4 O 5 I 2 microspheres with rich oxygen vacancies exhibits an excellent photocatalytic activity and durability. • Possible photo-induced charges transfer mechanism and photocatalytic reaction mechanism were proposed. A 3D hierarchical metallic Bi modified Bi 4 O 5 I 2 microspheres with rich oxygen vacancies (Vos) was successfully prepared via a one-pot solvothermal method. In this work, the different morphologies of BiOI and Bi modified Bi 4 O 5 I 2 were prepared by precipitation, hydrothermal and solvothermal methods. It was discovered that using the solvothermal method with ethylene glycol as the solvent could not only prepare microspheres Bi 4 O 5 I 2 with rich oxygen vacancies but also control the content of Bi by changing the reaction duration. The doping of metallic Bi created a built-in electric field between Bi and Bi 4 O 5 I 2 , which is helpful to improve the efficiency of carrier separation. Benefited from the synergistic effect of oxygen vacancies and built-in electric field, the as-prepared Bi/Bi 4 O 5 I 2 exhibits an excellent mercury removal efficiency, high-performance stability, and satisfactory sulfur resistance as well as nitric oxide resistance. Finally, the mechanism of catalytic oxidation reaction was proposed, photo-generated holes and superoxide radicals were predominant in the photocatalytic reaction. [ABSTRACT FROM AUTHOR]

The carbon modified BiOI/BiOIO 3 (CSs-BiOI/BiOIO 3 ) composites with heterostructures have been prepared via a facile hydrothermal method, using carbon spheres, bismuth nitrate and potassium iodate as precursors. Moreover, a new synthesis mechanism has been proposed. The photocatalytic activities of as-prepared catalysts are evaluated by oxidation of gaseous elemental mercury under visible light irradiation. It is found that the CSs-BiOI/BiOIO 3 exhibits highly enhanced visible photocatalytic activity, compared with that of pure BiOIO 3 . The results show that the Hg 0 removal efficiency of CSs-BiOI/BiOIO 3 reach up to 92.9% and 83.0% under LED light irradiation and simulated sunlight irradiation respectively. The improved photocatalytic activity can be ascribed to the increased the absorption of visible light, enhanced charge separation and transfer and the surface properties. This work points to CSs-BiOI/BiOIO 3 nanocomposites as new and efficient visible light photocatalysts for environmental remediation applications. [ABSTRACT FROM AUTHOR]