A 2D/2D S-scheme photo-Fenton catalyst based on ultrathin Bi2MoO6 and Fe2O3 hexagonal nanosheets for efficient tetracycline degradation

Abstract

In order to solve the increasingly serious environmental pollution and energy crisis as soon as possible, engineering of two-dimensional/two-dimensional (2D/2D) S-scheme heterojunctions is in the spotlight. Herein, two-dimensional/two-dimensional (2D/2D) S-scheme Fe₂O₃/Bi₂MoO₆ was designed and fabricated through a facile hydrothermal strategy, which constructed an advanced photocatalytic-Fenton coupling system. With the assistance of a low concentration of H₂O₂, the 2D/2D Fe₂O₃/Bi₂MoO₆ with an Fe₂O₃ weight ratio of 0.5% displayed significantly enhanced photo-Fenton catalytic activity toward tetracycline, which was 3.2 and 2.0 times that of Fe₂O₃ and Bi₂MoO₆, respectively. The markedly enhanced photo-Fenton catalytic activity was attributed to the large surface area and efficient charge transfer of 2D/2D S-scheme Fe₂O₃/Bi₂MoO₆, as well as the photo-Fenton system constructed by H₂O₂ and continuous Fe³⁺/Fe²⁺ conversion under visible light irradiation. According to the active species trapping experiments and photoluminescence spectra, a novel 2D/2D S-scheme charge transfer mechanism of Fe₂O₃/Bi₂MoO₆ was reasonably proposed. Fe₂O₃/Bi₂MoO₆ composites displayed a broad application prospect due to their recyclability demonstrated by the cycling experiments. This work provides strong evidence that 2D/2D S-scheme Fe₂O₃/Bi₂MoO₆ heterostructures are promising candidates for the photo-Fenton treatment of antibiotics.