Construction of CeO2/BiOI S-scheme heterojunction for photocatalytic removal of elemental mercury

In this work, a series of CeO2/BiOI S-scheme heterojunction photocatalysts were prepared through a simple coprecipitation and hydrothermal method. In addition, various characterization methods were adopted to confirm the successful preparation of the photocatalyst, and density functional theory (DFT) was applied to evaluate and calculate the band structure, density of states and electrostatic potential, and to further determine the construction of the S-scheme heterojunction. Furthermore, photocatalytic activity of the samples was evaluated by removing Hg0 under visible light, and the mechanism of photocatalytic mercury removal was proposed. The experimental results show that compared with single CeO2 and BiOI, the photocatalytic activity of the prepared CeO2/BiOI S-structure heterojunction has been significantly improved. Moreover, the significant enhancement of photocatalytic activity not only benefits from Ce4+/Ce3+ activation centers and oxygen vacancies, but also from the S-scheme heterojunction. This work provides effective guidance for exploring the effective construction of Bibased composite photocatalysts with S-scheme heterojunctions.