Aqueous Synthesis and Photocatalytic Performance of Bi5O7I Microflowers

Bi5O7I microflowers were synthesized through a simple liquid coprecipitation under alkaline condition at 75 degrees C in an open system without using autoclave or other complex equipment. The addition of NaBr was a key factor for controlling the morphology of Bi5O7I. The assembled Bi5O7I samples are constructed by elementary nanowires, which were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis diffuse reflection spectroscopy (UV-Vis DRS) methods. The photocatalytic performance of Bi5O7I samples on rhodamine B (RhB), methylene blue (MB) and ciprofloxacin (CIP) was evaluated under 350 W xenon lamp irradiation. On comparison with the blank Bi5O7I microflowers, Bi5O7I microflowers with NaBr addition exhibited better photocatalytic performance, and the photocatalytic activity enhanced with the increase of NaBr amount. The photocatalytic efficiency reached 81.1% in 150 min for RhB, 42.5% in 210 min for MB and 56.3% in 210 min for CIP in the degradation system at pH = 7 without any assistant agent. Trapping experiments were performed to reveal the degradation mechanism of Bi5O7I samples. It was proposed that valid separation of photogenerated electrons and holes in Bi5O7I microflowers led to good catalytic properties.