Solvothermal synthesis of a peony flower-like dual Z-scheme PANI/BiOBr/ZnFe2O4 photocatalyst with excellent photocatalytic redox activity for organic pollutant under visible-light

In present study, polyaniline/bismuth bromide/zinc ferrite (PANI/BiOBr/ZnFe2O4) was rationally designed and successfully prepared via a facile hydrothermal synthesis method. The crystal structure, chemical composition and morphology of the samples were analyzed by various characterization techniques. The PANI/BiOBr/ZnFe2O4 composite exhibits a higher photocatalytic activity compared with other samples under visible light irradiation. Among 611 samples, the highest degradation efficieney for RhB over 7% PANI/BiOBr/ZnFe2O4 reach 99.26%. Meanwhile, the composite exhibits an excellent catalytic activity for the reduction of nitrobenzene (NB) under visible light, the conversion efficiency can reach 87.1%. Moreover, the ternary composite still maintains a higher photocatalytic activity after three consecutive uses. Additionally, according to PL spectra and electrochemical impedance spectroscopy (EIS), the improved photocatalytic performance of PANI/BiOBr/ZnFe2O4 composite can be attributed to the rapid separation and transfer of electron-hole pairs. Finally, the dual Z-scheme electron transfer mechanism suitable for this system was proposed by UV-vis DRS spectra, M-S curves analysis, ESR spectra and free radical capture experiments. This study provides a new research idea for the design and construction of efficient photocatalysts for organic pollutants and other water treatment problems.