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

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.