Highly efficient removal of 2,4‐dichlorophenal over a novel dual Z‐scheme heterojunction of Bi7O9I3/BiOIO3/g‐C3N4 under visible‐light irradiation: performance and mechanism

摘要

Abstract BACKGROUND 2,4‐Dichlorophenol (2,4‐DCP) is widely used as a preservative, pesticide, germicide, etc. However, it is very damaging to organisms and the environment, and it is difficult to decompose because of its high stability. To improve the photocatalytic ability of photocatalysts for degrading hazardous substances, like 2,4‐DCP, constructing heterojunction is an effective strategy because of its restraint of electron–hole recombination and extension of light absorption spectra. RESULTS A novel photocatalyst Bi7O9I3/BiOIO3/g‐C3N4 was successfully synthesized by one‐step in‐situ co‐crystallization method. The formation of Bi7O9I3/BiOIO3/g‐C3N4 composite was confirmed by X‐ray diffractometer (XRD), X‐ray photoelectron spectroscopy (XPS), fourier transform infrared spectrometer (FTIR spectrometer) and transmission electron microscope (TEM). The obtained optimal composite exhibited an excellent photocatalytic performance of degrading 2,4‐DCP with an efficiency of 95 under visible‐light irradiation. The trapping experiments indicated that superoxide radicals, electrons, and singlet oxygen played vital roles in 2,4‐DCP decomposition and confirmed the dual Z‐scheme heterojunction structure of Bi7O9I3/BiOIO3/g‐C3N4. Furthermore, the possible reaction pathway was deduced based on the trapping experiments and the intermediate products detected by liquid chromatography tandem mass spectrometry. CONCLUSION The photocatalytic performance of Bi7O9I3/BiOIO3/g‐C3N4 was enhanced because the more efficient separation and transfer of photogenerated charge carriers was achieved due to the formation of dual Z‐scheme heterojunction. This work presented a simple and feasible synthesis method to prepare a ternary photocatalyst for improving the photocatalytic ability, and it can assist in further understanding the reaction mechanism of 2,4‐DCP degradation. © 2022 Society of Chemical Industry (SCI).