Synthesis of novel p-n heterojunction m-Bi2O4/BiOCl nanocomposite with excellent photocatalytic activity through ion-etching method

A novel p-n heterostructure photocatalyst m-Bi 2 O 4 /BiOCl was successfully synthetized through a facile ion-etching method. Via adjusting the added volume of HCl solution, a series of different ratios of composite photocatalysts were obtained. The as-prepared samples of physical, chemical and optical characteristics were examined by X-ray diffraction, scanning electron microscope, transmission electron microscope, energy dispersive X-ray spectroscopy, selected-area electron diffraction, Fourier transform infrared absorption, Raman microscope, N 2 adsorption-desorption, X-ray photoelectron spectroscopy and UV-vis spectrum technologies. The photocatalysts showed high degradation rate and complete mineralization ability for methyl orange and tetracycline solution under visible light. The reaction rate constant of m-Bi 2 O 4 /BiOCl for methyl orange was 52.28 times higher than that of BiOCl. The characterization presented a good stability of materials. Furthermore, the photocurrent response test certified that the heterostructure effectively accelerated the separation and migration of photo-generated carries. The scavenger experiments evidenced that hole (h + ) and superoxide radical (•O 2 — ) were the primary active radicals. A possible photocatalytic mechanism was proposed. This work provided an alternative photocatalyst applied to water environmental remediation.