One-step synthesis of composite semiconductor AgBr/Ag5P3O10 heterojunctions and their photocatalytic activity, kinetic analysis, photocatalytic mechanism under visible light radiation

A composite semiconductor AgBr/Ag5P3O10 heterojunction has been synthesized by a simple one-step ion-exchange process in Br ionic liquids. All the as-obtained AgBr/Ag5P3O10 heterojunctions were characterized by X-ray powder diffraction (XRD), scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), Brunauer–Emmett–Teller (BET), UV–vis absorption spectroscopy (UV–vis), photoluminescence (PL), and surface photovoltage (SPS) techniques. The as-prepared AgBr/Ag5P3O10 heterojunctions intensively absorb in the visible light region. The effects of different conditions on the photocatalytic properties were investigated systematically. The AgBr/Ag5P3O10 heterojunctions exhibited an enhanced photocatalytic activity than the individual Ag5P3O10 did in the degradation of methylene blue (MB) under visible-light irradiation. Much more OH radicals were found in the AgBr/Ag5P3O10 system in comparison with those in Ag5P3O10 alone by analyzing the formed OH radicals under visible light radiation. The SPS measurement shows that the SPS amplitude of AgBr/Ag5P3O10 heterojunctions was higher than that of Ag5P3O10, which indicates the higher charge separation efficiency of AgBr/Ag5P3O10 heterojunctions. Based on the above experimental results, the kinetic data and the photocatalytic mechanism of the AgBr/Ag5P3O10 heterojunctions were discussed in detail.

► AgBr/Ag5P3O10 heterojunctions showed higher activity than that of Ag5P3O10.
► The high activity could be attributed to AgBr for modifying Ag5P3O10.
► More OH radicals may be significant reason to improve Ag5P3O10 activity.