Efficient Removal of Tetracycline Hydrochloride Under Visible-Light Irradiation with Novel Fe/Biobr/Bioi Photocatalyst Prepared by Dual Modification Strategy

Abstract

Abstracts Bismuth oxyhalide (BiOX, X=Cl, Br, I) species with tunable microstructures, abundant surface active centres, excellent electrical conductivity, and good photocatalytic properties have become important basic materials in the field of photocatalysis. However, pure BiOX and BiOX materials modified with a single strategy have limited photocatalytic performance due to the rapid recombination of photogenerated electron-hole pairs. Therefore, combining two different modification strategies to synergistically improve the photocatalyst activity of BiOX should be investigated. In this manuscript, iron-doped BiOBr/BiOI heterojunctions were synthesised using a one-pot solvothermal method for the photocatalytic degradation of tetracycline hydrochloride (TCH) in water. The synergistic effect between iron ion doping and BiOBr/BiOI heterojunction formation was elucidated by combining photocatalytic experiments and material characterisation. The Fe/BiOBr/BiOI composite photocatalyst possessed a good bandgap structure, which enhanced its visible light response and effectively suppressed the recombination of photogenerated electron-hole pairs. Thus, photocatalytic activity was improved. Photocatalytic degradation experiments showed that Fe/BiOBr/BiOI effectively removed TCH from aqueous solution under visible light irradiation, with the removal rate reaching 99% after 60 min of visible light irradiation. In addition, Fe/BiOBr/BiOI still possessed good photocatalytic activity after six recovery-cycling experiments, demonstrating its stability. Finally, the separation of photoexcited carriers and the doping mechanism of the iron ions were determined by combining the experimental results and characterisation data. This study provides a new direction for designing efficient photocatalysts.

Keywords: Fe/BiOBr/BiOI, Fe doping, Dual strategy, Tetracycline hydrochloride, Photodegradation