Fabrication of AgI/BiPO4 n–n heterojunction photocatalyst for efficient degradation of organic pollutants

The AgI/BiPO 4 n–n heterojunction hybrids were favorably fabricated over amorphous particles AgI closely in contact with petty polyhedron-assembled star-like BiPO 4 by precipitation technology for the first time. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–Vis diffuse reflectance spectra (DRS), electrochemical test, etc. The degradation of tetracycline hydrochloride (TC) and methylene blue (MB) was employed to testify the performance of as-prepared composites upon exposure of simulated solar light and the AB-X composites exhibited boosted degradation efficiency in comparison with the as-prepared pure BiPO 4 and AgI. For instance, the calculated k TC of pseudo-first-order kinetics model on 24 wt% AgI/BiPO 4 sample was 36 times relative to those on pure BiPO 4 . This enhanced activity might due to increased charge transfer and separation efficiency in the formed n–n heterojunction and the dominant reaction active species were authenticated by trapping experiments. Furthermore, the internal electric field in the AgI/BiPO 4 heterojunction and the transfer path of electron–holes were tentatively deduced through graphical elucidation.