Z-scheme Bi2MoO6 nanoplate-decorated flower-like Bi12SiO20 for efficient photocatalytic degradation of organic pollutants

A novel Z-scheme Bi2MoO6/Bi12SiO20 (MS) heterojunction, with 2D nanoplates of Bi2MoO6 anchored on the surface of flower-shaped Bi12SiO20 particles, was synthesized via simple solvothermal process for the first time. A series of techniques including XRD, XPS, SEM, TEM, BET, UV–vis DRS and Mott–Schottky were used for characterizing the photocatalysts. The MS0.6 (the heterojunction with a Bi2MoO6/MS mass ratio of 0.6:1) exhibited optimal photocatalytic activity for degrading RhB, and the reaction rate constant achieved 0.041 min−1, which was 41 and 4.6 times that of Bi12SiO20 and Bi2MoO6, respectively. The MS0.6 also presents outstanding activity for the degradation of BPA (0.014 min−1), which was 3.5 and 14 times that of Bi12SiO20 and Bi2MoO6, respectively. Furthermore, the UV–vis absorption spectrum and TOC test confirmed that the mineralization capacity of Bi2MoO6 was significantly enhanced after coupling with Bi12SiO20. The enhanced performance was attributed to the improved light absorption and excellent separation efficiency of photo-induced carriers. Trapping and ESR experiments indicated that h+ and •O2− jointly dominated the degradation of RhB. Therefore, a reliable Z-scheme mechanism was proposed. Additionally, MS0.6 presented a good stability and durability in four catalytic runs. This study provides an insight for designing highly efficient Z-scheme Bi12SiO20-based photocatalysts for the practical sewage disposal.