Study on highly efficient p-n heterojunction Bi2MoO6/Cu2O: Synthesis, characterization and visible-light photocatalytic activity toward antibiotics degradation

Water pollution has reached alarming levels due to the overuse of antibiotics, and photocatalysis is considered to be a green and efficient degradation technology for the treatment of water pollution caused by antibiotics. In this paper, a series of p-n heterojunction Bi 2 MoO 6 /Cu 2 O composite photocatalysts were synthesized by hydrothermal method . The samples were characterized by XRD, SEM, XPS, UV–Vis-DRS, PL , and EIS . The photocatalytic activities of the photocatalysts were analyzed based on the degradation of two antibiotics under visible light illumination. Results showed a removal rate of 88% and 94% for chlortetracycline (CTC) and tetracycline (TC), respectively. The corresponding first-order kinetic curves indicated that the reaction rates were 4.2 and 7.9 times higher than those of the Bi 2 MoO 6 and Cu 2 O monomers . The enhanced removal efficiency of antibiotics is ascribed to the improved light absorption and electron-hole pair transport channels, facilitated by the formation of p-n heterojunction within the catalyst. Further, a possible degradation mechanism was proposed. Finally, the intermediate products were analyzed using liquid chromatography-mass spectrometry (LC-MS), and a possible photocatalytic degradation pathway of CTC was proposed. Based on the present study and experimental observations, Bi 2 MoO 6 /Cu 2 O as a visible-light-driven photocatalyst is suggested to be a promising candidate for the removal of antibiotics.