Shape-dependent photocatalytic activity of Bi5O7I caused by facets synergetic and internal electric field effects

Abstract

Bi₅O₇I rods and Bi₅O₇I sheets based photocatalytic materials were synthesized by a hydrothermal method and solid phase conversion, respectively. They were characterized by X-ray diffraction patterns (XRD), selected area electron diffraction (SAED), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and UV-vis diffuse reflectance spectroscopy (DRS). The photocatalytic results showed that Bi₅O₇I had shape-dependent photocatalytic activity. Bi₅O₇I rods showed considerably higher photocatalytic activity than Bi₅O₇I sheets for the degradation of dyes. Photoluminescence (PL) spectra, active species trapping and theoretical calculations were studied to analyze the photocatalytic mechanisms of the shape-dependent photocatalytic activity. It revealed that Bi₅O₇I rods with {001} and {100} facets exposure resulted in synergetic and internal electric field effects. Higher separation efficiency of photogenerated carriers and photocatalytic activity were observed for the Bi₅O₇I rods.