Based on a dual Z-scheme heterojunction and magnetically separable CoFe2O4/g-C3N4/Bi4Ti3O12 flower-like composite for efficient visible-light photocatalytic degradation of organic pollutants

A novel magnetic CoFe2O4/g-C3N4/Bi4Ti3O12 composite photocatalyst has been successfully prepared via an ultrasonic-assisted heat treatment method for the degradation of malachite green (MG) dye in wastewater. The crystal structure, element composition, morphology, and optical properties of the as-prepared samples are investigated by a series of characterization techniques. The maximum degradation rate for MG reaches 98.05% over 40%-CoFe2O4/g-C3N4/Bi4Ti3O12 composite after optimizing the dosage and concentration, which is better photocatalytic activity than pure Bi4Ti3O12 and g-C3N4/Bi4Ti3O12. In addition, CoFe2O4/g-C3N4/Bi4Ti3O12 can be conveniently separated from the reaction system by the external magnetic field and reused multiple times. The characterization shows that the enhanced activity of CoFe2O4/g-C3N4/Bi4Ti3O12 is mainly due to the formation of heterojunction, promoting the separation efficiency of photogenerated electron-hole (e (-)/h(+)) pair. The capture experiments and EPR spectra show that the main active substances are h(+) and center dot O-2(-) for decomposing MG in the reaction system. Then, a dual Z-scheme heterojunction electron transfer mechanism is proposed. This study provides an idea for cycle stable magnetic photocatalysts for the treatment of MG solution. (c) 2022 Elsevier B.V. All rights reserved.