Room-temperature controllable synthesis of Bi5O7I nanostrips for improved photocatalytic activity

Abstract

Photocatalysis is recognized as one of the most promising technologies to purify environmental pollutants. As a member of the bismuth oxyhalogen family, Bi-rich Bi5O7I photocatalyst has drawn intense attention due to its unique layered structure and visible-light absorption. In previous work, Bi5O7I is mainly prepared through the hydrothermal or solid-state reactions, which suffer from the drawbacks of high temperature, high-pressure and long reaction time. Herein, a simple room-temperature hydrolysis method was developed to prepare the uniform Bi5O7I nanostrips by using BiOI as the precursor. With addition of different surfactants, including CTAB, SDBS and PVP, the as-obtained Bi5O7I nanostrips display different length/diameter ratio. The photocatalytic degradation experiments showed that PVP-Bi5O7I with the largest aspect ratio exhibits the most efficient photocatalytic activity for degradation of tetracycline hydrochloride, which is attributed to the highest charge separation efficiency and largest specific surface area of PVP-Bi5O7I derived from its unique microstructure. In addition, the quantitative determination of superoxide radicals (O2−) generated in the photocatalytic process was conducted to clarify the degradation mechanism. This study provides a reference for facile and scalable preparation of nanostructured photocatalysts for future practical applications.