Preparation of CuFe2O4/In2S3 composite for photocatalytic degradation of tetracycline under visible light irradiation

The CuFe 2 O 4 /In 2 S 3 composite was prepared by a simple mechanical grinding process and used for the photocatalytic degradation of tetracycline (TC) under visible light irradiation. The results showed that the photocatalytic degradation activity for tetracycline on the CuFe 2 O 4 /In 2 S 3 composite photocatalyst with a mass ratio of 1:3 was 95.2%, which was higher than that of 12 and 63% on pure CuFe 2 O 4 and In 2 S 3 alone, as well as 89% on CuFe 2 O 4 /In 2 S 3 (1:1) and 79% on CuFe 2 O 4 /In 2 S 3 (3:1). Tetracycline photodegradation on CuFe 2 O 4 /In 2 S 3 was a first-order reaction, and the rate constant of the tetracycline degradation reaction under visible light irradiation was 0.02162 min −1 , which was 38 and 3.1 times higher than that of CuFe 2 O 4 and In 2 S 3 alone, respectively. This characterization results showed that CuFe 2 O 4 /In 2 S 3 (1:3) composites showed the high photodegradation efficiency and the highest photogenerated carrier separation efficiency. In addition, on the optimal reaction condition, an optimal photodegradation of 95.2% for tetracycline would achieved. The stable construction of the CuFe 2 O 4 /In 2 S 3 heterojunction and the narrow band gap of CuFe 2 O 4 or In 2 S 3 enhance the light absorption capacity of the catalyst. The mechanism study shows that CuFe 2 O 4 and In 2 S 3 are excited by visible light to produce electrons, which transfer to the conduction band of CuFe 2 O 4 and In 2 S 3 . Subsequently, the separation and transfer of photogenerated holes and photogenerated electrons are effectively improved by the Z-scheme photogenerated carrier transfer mechanism. The photogenerated electrons can reduce O 2 to produce ·O 2 − , which together with h + on the valence band becomes the main oxidation active species in the reaction system, and efficient oxidative degradation of tetracycline can be achieved.