Preparation of Fe-doped In2S3/In2O3 Composite for Photocatalytic Degradation of Tetracycline

Tetracycline (TC) is not only a threat to aquatic ecosystems and the health of organisms but also a crucial contributor to the drug resistance of bacteria. The photodegradation of TC is an effective strategy for overcoming antibiotic pollution in the water environment. Fe-In2O3/In2S3 composites were successfully synthesized via a hydrothermal method for the photocatalytic degradation of TC under visible light illumination. When the Fe doping content was 2%, the degradation rate of TC by the 2% Fe-In2O3/In2S3 composite under visible light irradiation reached 92.4%, which was higher than that of 41.5% for In2O3/In2S3, 86.7% for 1% Fe-In2O3/In2S3 and 79% for 3% Fe-In2O3/In2S3. The photodegradation of tetracycline on Fe-In2O3/In2S3 was a first-order reaction under visible light. The rate constant of photocatalytic tetracycline degradation was 5.12 x 10(-3) min(-1), which was 4.1 times greater than the rate constant of In2O3/In2S3. The characterization results revealed the excellent separation efficiency of the 2% Fe-In2O3/In2S3 composites for photogenerated electron-hole pairs, which increased the photodegradation efficiency. Furthermore, under the most suitable reaction conditions, the photodegradation rate of tetracycline was 92.4%. A mechanistic study revealed that the doping of Fe ions effectively improved the transfer efficiency of photoproduced charges and inhibited the combination of photoproduced electron-hole pairs, thereby improving the photocatalytic performance of the material and achieving efficient oxidative degradation of tetracycline.