Room temperature synthesis of Bi4O5I2 and Bi5O7I ultrathin nanosheets with a high visible light photocatalytic performance

Abstract

Bi₄O₅I₂ and Bi₅O₇I ultrathin nanosheets are prepared via a facile route at room temperature. The composition, morphology, energy bands and photocatalytic properties of the materials are investigated systematically using different characterization techniques. The results reveal that Bi₄O₅I₂ and Bi₅O₇I can be easily obtained by adjusting the OH⁻ concentration at different pH values. Both Bi₄O₅I₂ and Bi₅O₇I have the morphology of ultrathin nanosheets and a high surface area. With the increase of the Bi content, the adsorption edge of the samples shifts towards a shorter wavelength and the valence band edge potential becomes more positive. Thus, they exhibit a superior photocatalytic efficiency for the degradation of phenol under visible light irradiation compared to BiOI.