Preparation of high-performance α-Bi₂O₃ photocatalysts and their photocatalytic activity

In the present work, α-bismuth (III) oxide (α-Bi₂O₃) photocatalysts with a porous and nanosheet structure were prepared by using the biomimetic-synthesis-assisted hydrothermal method. l-Arginine (C₆H₁₄N₄O₂) was used as the biomimetic template, and the pH value range of the precursor solution was 3–12. The as-obtained samples were characterized by X-ray diffraction, field-emission scanning electron microscopy and ultraviolet–visible diffuse reflectance spectroscopy. The photocatalytic activity of photocatalysts was evaluated by using rhodamine B (RhB; C₂₈H₃₁ClN₂O₃), tetracycline hydrochloride (TC-HCl; C₂₂H₂₄N₂O₈·HCl) and methyl orange (MO) as the targeted degradants under visible light irradiation. The results show that α-bismuth (III) oxide exhibits a high photocatalytic activity when the pH value of the precursor is 3 and the l-arginine content is 0.03 mol/l. Under the co-catalysis of hydrogen peroxide (H₂O₂), the degradation efficiencies of RhB, TC-HCl and MO are 75.3, 68.1 and 63.8%, respectively. The degradation rate of α-bismuth (III) oxide as prepared by using l-arginine for RhB degradation is about 2·09 times faster than that of template-free α-bismuth (III) oxide. The high photocatalytic activity is mainly attributed to the porous structure and high visible light response range of the α-bismuth (III) oxide photocatalyst.