Direct Z-Scheme CoFe₂O₄-Loaded g-C₃N₄ Photocatalyst with High Degradation Efficiency of Methylene Blue under Visible-Light Irradiation

Abstract

Magnetically recyclable direct Z-scheme CoFe₂O₄-loaded g-C₃N₄ photocatalyst material was fabricated using a facile hydrothermal technique and subsequently characterized by XRD, VSM, PL, FT-IR, EDX, DRS, SEM, and BET techniques. The characterization results confirmed that nanoparticles of CoFe₂O₄ are loaded on the surface of g-C₃N₄ sheets. The optical band gap of g-C₃N₄ has been decreased from 2.65 eV to 1.30 eV by means of the loading of CoFe₂O₄ nanoparticles onto the nanosheets of g-C₃N₄. This has enhanced the separation process of electron-hole. Under visible light irradiation, the photocatalytic activity of the developed direct Z-scheme CoFe₂O₄-loaded g-C₃N₄ photocatalyst was evaluated for the photodegradation of methylene blue (MB); during this process the MB decomposed by up to 98.86% in 140 min. Meanwhile, under the same irradiation and time conditions, the g-C₃N₄ and CoFe₂O₄ themselves degraded MB up to 74.92% and 51.53%, respectively. The direct Z-scheme CoFe₂O₄-loaded g-C₃N₄ material was recovered from the solution after the photocatalytic activity using an external magnet and studied to determine its stability. It was shown that the photoactivity did not change significantly after five consecutive cycles.