Preparation of Bi_3.64Mo_0.36O_6.55 by reflux method and its application in photodegradation of organic pollution

Bismuth molybdate (γ-Bi₂MoO₆) photocatalyst has garnered huge attention in the field of photocatalysis because of its band gap (2.5–2.8 eV) and good visible-light response (420 ≤ λ ≤ 500 nm). However, as a kind of bismuth molybdates, there are only few studies on Bi_3.64Mo_0.36O_6.55 (BMO), thus further exploration is needed. Herein, a simple reflux method was developed to synthesize the cubic phase of BMO. This method is simple and easy to operate under atmospheric pressure, showing great potential for large-scale production. In contrast with the nanosheet structure of Bi₂MoO₆, the morphology of BMO is a mixture of nanorod and nanoparticle-like structure. The band structures showed that the band gap, conduction band position and the valence band position of BMO was 2.77 eV, − 0.33 eV and 2.44 eV, respectively. A new mixed phase of 3Bi₂O₃·2MoO₃ appeared in BMO crystal, showing that the phase transition of BMO began at 400 °C. When BMO was calcined at 300 °C, photocatalytic degradation rate was up to maximum. The photocatalytic activity of visible-light range was tested and compared with γ-Bi₂MoO₆. BMO had better photodegradation activity than that of the Aurivillius phase γ-Bi₂MoO₆ due to its larger band gap and strong oxidation ability.