Preparation of Bi2O2CO3/BiOBr0.9I0.1 photocatalyst and its degradation performance for 2,4-dichlorophenoxyacetic acid

Abstract

Pesticide pollution has caused serious harm to the ecological environment and presents a major risk to human health due to drinking water resource contamination. 2,4-dichlorophenoxyacetic acid (2,4-D), as a class II toxic compound, can cause human health hazards, including neurotoxicity, hepatotoxicity, nephrotoxicity, reproductive defects and abortion. In this study, pure Bi2O2CO3/BiOBr0.9I0.1 photocatalyst material was prepared for the degradation of pesticides using a solvothermal method. The structure, morphology, and optical properties of the photocatalyst were characterized through X-ray diffraction (XRD), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra (DRS), Steady-state photoluminescence (PL), and Electrochemical Impedance Spectroscopy (EIS). The Bi2O2CO3/BiOBr0.9I0.1 catalyst could degrade 89.1% of 2,4-D within 120 min under visible light. After four cycles of reuse, Bi2O2CO3/BiOBr0.9I0.1 retained a high degradation performance for 2,4-D. The results of active substance capture experiments and ESR, showed that ·O2- and h+ were the main active substances. Under the synergistic effects of heterojunction and the solid solution, 10 wt%Bi2O2CO3/BiOBr0.9I0.1 was able to efficiently photocatalyze 2,4-D degradation. The use of the double modification method of solid solution and heterojunction construction regulates the band structure of BiOBr, resulting in a high photogenerated carrier separation efficiency and good light response capability. The Z-type heterojunction provides the photogenerated carriers with a high redox capacity. The synergistic effect of the two modification strategies results in the BiOBr based composite photocatalyst exhibiting excellent visible photocatalytic activity.