Constructing 3D Bi/Bi4O5I2 microspheres with rich oxygen vacancies by one-pot solvothermal method for enhancing photocatalytic activity on mercury removal

A 3D hierarchical metallic Bi modified Bi4O5I2 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 Bi4O5I2 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 Bi4O5I2 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 Bi4O5I2, 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/Bi4O5I2 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.