Photocatalytic performance of dual Z-scheme CoFe2O4/α-Fe2O3/Co3O4 ternary heterojunction composite synthesized by Pechini method

Abstract

This work presents the synthesis of a dual Z-scheme CoFe2O4/α-Fe2O3/Co3O4 ternary heterojunction composite (THC), as well as CoFe2O4 (CFO) nanoparticles (NPs) by the Pechini method and their solar-driven photocatalytic performance for the degradation of methylene blue (MB) dye. FT-IR spectroscopy, X-ray diffraction analysis, and Raman spectroscopy were used to confirm the presence of the respective phases in the THC and CFO NPs. Morphology analysis revealed that the THC consisted of disk-shaped and octahedron-shaped particles, while the CFO NPs comprised octahedral and icosahedral particles. After 120 min of sunlight irradiation, the THC system demonstrated superior photocatalytic performance with degradation efficiencies of 68.7 %, 82.3 %, and 88.5 % in aqueous media containing 20, 10, and 5 mg/L of MB, respectively. The enhanced photocatalytic performance of THC is attributed to both α-Fe2O3 and Co3O4 acting as electron mediators in a dual Z-scheme heterojunction mechanism. Besides, the THC demonstrated to have higher first-order kinetics constants than CFO NPs and excellent stability and reusability over four cycles. Finally, the experiments of radical scavengers demonstrated that the main active species for decomposing MB in this system were ·OH and ·O2− active radicals.