Enhanced visible-light photocatalytic activity of g-C3N4/LaFeO3 heterojunctions for the removal of tetracycline hydrochloride

LaFeO3 nanoparticles were synthesized with hydrothermal method and g-C3N4 nanosheets were prepared from bulk g-C3N4 in alkaline solution, and then g-C3N4/LaFeO3 nanocomposites were successfully synthesized via electrostatic self-assembly method. All samples were characterized by XRD, TEM, TGA, BET and UV-vis, which indicates that LaFeO3 nanoparticles are well-dispersed on g-C3N4 nanosheets to form g-C3N4/LaFeO3 nano-composites. The photocatalytic activity of g-C3N4/LaFeO3 nanocomposites to tetracycline hydrochloride (TC-HCl) antibiotics under visible light irradiation is investigated and optimized in detail, indicating the excellent photocatalytic activity and chemical stability. The degradation efficiency of TC-HCl with 35%CNS/LF is 13.6-fold and 2.6-fold higher than those of pristine LaFeO3 nanoparticles and g-C3N4 nanosheets. The interface of g-C3N4/LaFeO3 p-n heterojunctions effectively separates the photogenerated electrons and holes, leading to the higher photocatalytic activity. Moreover, active species trapping experiments reveal that center dot O-2(-) is the dominant radical during photodegradation process.

Automated summary

In this study, g-C3N4/LaFeO3 nanocomposites were successfully synthesized with well-dispersed LaFeO3 nanoparticles on g-C3N4 nanosheets. The g-C3N4/LaFeO3 nanocomposites exhibited excellent photocatalytic activity for the degradation of tetracycline hydrochloride (TC-HCl) antibiotics under visible light irradiation, with a degradation efficiency 13.6-fold and 2.6-fold higher than pristine LaFeO3 nanoparticles and g-C3N4 nanosheets, respectively. The p-n heterojunctions of g-C3N4/LaFeO3 effectively separated photogenerated electrons and holes, leading to the enhanced photocatalytic activity. Moreover, the dominant radical during the photodegradation process was found to be center dot O-2(-) according to active species trapping experiments.