Rational construction of α-Fe2O3/g-C3N4 heterojunction for effective photo-Fenton-like degradation of tetracycline

A novel α-Fe2O3/g-C3N4 composite was successfully designed by loading α-Fe2O3 hexagonal flakes on the spherical surface of g-C3N4 to enhance visible light absorption and manipulate the directed transfer of electrons and holes. The results of UV–vis DRS, XPS valence band, and Mott-Schottky calculations indicated that the g-C3N4 microspheres obtained after morphology modulation have improved absorption of visible light and the band gap structure has been changed. The catalyst achieved 90.7% removal of tetracycline in 120 min under visible light irradiation and hydrogen peroxide, which was 58.2 and 37.6% higher relative to the photocatalytic and Fenton-like systems alone, respectively. It was shown that the significantly enhanced catalytic activity was attributed to the synergistic effect of α-Fe2O3 and g-C3N4. In addition, the possible degradation pathways of tetracycline were investigated by HPLC-MS to identify intermediates. This work provided insight into the construction of Z-scheme heterojunction photo-Fenton catalysts for environmental remediation.