An anion exchange strategy to synthesize BiPO4/BiOCl heterojunction at room temperature with efficient photocatalytic performance

Abstract

Photocatalytic degradation efficiency largely depends on the oxidation capacity of semiconductors. Among various kinds of alternative semiconductors, BiPO4 has a strong photooxidation ability. However, the synthesis of BiPO4 or BiPO4-based composites always requires high temperature due to the unique structure of BiPO4. Herein, BiPO4/BiOCl heterojunction photocatalysts were successfully fabricated by an anion exchange strategy at room temperature. BiOCl precursor was converted to BiPO4/BiOCl under a PO43+-rich environment. BiPO4/BiOCl showed enhanced photocatalytic performance of phenol degradation than BiOCl. The conversion process, crystal structure and chemical properties of BiPO4/BiOCl heterojunctions were analyzed and characterized by XRD, SEM, TEM, UV–Vis DRS, XPS and FT-IR. Results displayed that hexagonal BiPO4 rods appeared and grew when adding PO43− anions to tetragonal BiOCl nanosheets suspension solution, which formed intimate p–n heterojunction interface between BiOCl and BiPO4. This paper provides a new strategy to synthesize BiPO4-based heterojunction photocatalysts at room temperature.