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 MS_0.6 (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 MS_0.6 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, MS_0.6 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. Graphical abstract: [Figure not available: see fulltext.].