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 Bi2WO6; 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.