Enhanced photocatalytic performance of boron doped Bi₂WO₆ nanosheets under simulated solar light irradiation.

Bi₂WO6 doped with different amounts of boron atoms (0.1, 0.5, 1.0, 5.0 and 10% B) were synthesized using hydrothermal method and their photocatalytic activities to degrade rhodamine B (RhB) under simulated solar light was investigated. The successful incorporation of B atoms in Bi₂WO₆ was proved by FT-IR, Raman spectra and XPS. Doping with B could affect the pore structure and volume. 0.5% B/Bi₂WO₆ displayed more mesopores with higher total pore volume than pure Bi₂W₆; while the pores of 10% B/Bi₂WO₆ mainly distributed in microporous range with much less total pore volume. As a result, 0.5% B/Bi₂WO₆ displayed stronger adsorption capacity to RhB, favoring the photodegradation. In addition, the doped B atoms could act as electron traps and facilitate the separation of photogenerated electron-hole pairs due to its electron deficient and oxytropic characteristics. 0.5% B/Bi₂WO₆ displayed the highest photocatalytic activity under simulated solar light with rate constant (kobs) 8.8 times of that using pure Bi₂WO₆. Its photoactivity was affected by solution pH and the optimum was achieved at pH 7. At this condition, around 100% of RhB (10(-5)mol/L) was degraded in 180 min. The photogenerated holes were the main active species responsible for the photodegradation of RhB by B/Bi₂WO₆.