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. 10-20nm 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.