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.

Automated summary

A novel magnetic CoFe2O4/g-C3N4/Bi4Ti3O12 composite photocatalyst with high activity and recyclability has been prepared for the degradation of malachite green dye in wastewater. The enhanced activity is attributed to the formation of heterojunction, promoting the separation efficiency of photogenerated electron-hole pairs.