Three-dimensional Ag2O/Bi5O7I p–n heterojunction photocatalyst harnessing UV–vis–NIR broad spectrum for photodegradation of organic pollutants

Ag2O nanoparticles-loaded Bi5O7I microspheres forming a three dimensional Ag2O/Bi5O7I p–n heterojunction photocatalyst with wide-spectrum response were synthesized in this study. The results of transmission electron microscopy observations revealed that the Ag2O nanoparticles with the diameter of ca. 10–20 nm were distributed on the surfaces of Bi5O7I nanosheets. The as-synthesized Ag2O/Bi5O7I exhibited an excellent wide-spectrum response to wavelengths ranging from ultraviolet (UV) to near-infrared (NIR), indicating its potential for effective utilization of solar energy. Compared with pure Bi5O7I, the Ag2O/Bi5O7I composite also demonstrated excellent photocatalytic activity for the degradation of Bisphenol A and phenol in aqueous solution under visible LED light irradiation. Among samples, the 20% Ag2O/Bi5O7I composite photocatalyst showed the highest photocatalytic activity for the degradation of Bisphenol A and phenol in aqueous solution. In addition, the 20% Ag2O/Bi5O7I composite also exhibited a photocatalytic activity for the degradation of Bisphenol A under NIR light irradiation. The improved photocatalytic activity is attributed to the formation of a p-n heterojunction between Ag2O and Bi5O7I, allowing the efficient utilization of solar energy (from UV to NIR) and high separation efficiency of photogenerated electron-hole pairs. The present work is desirable to explore a possible avenue for the full utilization of solar energy.