Boosting the activity for organic pollutants removal of In₂O₃ by loading Ag particles under natural sunlight...

A novel photocatalyst In₂O₃ with loading Ag particles is prepared via a facile one-step annealing method in air atmosphere. The Ag/In₂O₃ exhibits considerable photoactivity for decomposing sulfisoxazole (SOX), tetracycline hydrochloride (TC), and rhodamine B (RhB) under natural sunlight irradiation, which is much higher than that of pristine In₂O₃ and Ag species. After natural sunlight irradiation for 100 min, 70.6% of SOX, 65.6% of TC, and 81.9% of RhB are degraded over Ag/In₂O₃, and their corresponding chemical oxygen demand (COD) removal ratio achieve 95.4%, 38.4%, and 93.6%, respectively. A batch of experiments for degrading SOX with adjusting pollutant solution pH and adding coexisting anions over Ag/In₂O₃ are carried out to estimate its practical application prospect. Particularly, the as-prepared Ag/In₂O₃ possesses a superior stability, which exhibits no noticeable deactivation in decomposing SOX after eight cycles' reactions. In addition, the Ag/In₂O₃ coated on a frosted glass plate, also possesses a superior activity and stability for SOX removal, which solve the possible second pollution of residual powdered catalyst in water. Ag particles on In₂O₃ working as electron accepter improve charge separation and transfer efficiency, as well as the photo-absorption and organic pollutants affinity, leading to the boosted photoactivity of Ag/In₂O₃. The photocatalytic mechanism for degrading SOX and degradation process over Ag/In₂O₃ has been systemically investigated and proposed. This work offers an archetype for the rational design of highly efficient photocatalysts by metal loading.