Construction of Bi2WO6 with oxygen vacancies and investigation on mechanisms of significantly enhanced photocatalytic activity

Bi 2 WO 6 nanosheets with gradient oxygen vacancies were synthesized by acetic acid solvothermal and subsequent calcination. The photocatalytic activity of the calcined Bi 2 WO 6 was significantly enhanced. The calcination regulated the oxygen vacancy in Bi 2 WO 6 . Oxygen vacancy defects helped to adjust the band structure and change the surface chemical state. At the same time, the electrons were the main charge carriers of the n-type semiconductor Bi 2 WO 6 . Part of the electrons was captured by the oxygen vacancies to promote the separation of the holes. Some of the electrons reacted with oxygen to generate • O 2 – . The h + and • O 2 – were the main active species that degraded rhodamine B. Among them, Bi 2 WO 6 with 1 h of calcination at 315°C (Bi 2 WO 6 -315°C 1 h) exhibited the optimal photocatalytic activity. The degradation velocity of rhodamine B over Bi 2 WO 6 was 21.4 times that of Bi 2 WO 6 under the same reaction condition.