Sol–gel synthesis and enhanced photocatalytic activity of doped bismuth tungsten oxide composite

Abstract Pristine Bi 2 WO 6 and Bi 2 WO 6 /Bi 14 W 2 O 27 photocatalysts were synthesized by sol–gel method using Co(II) cation as dopant. The influence of Co dopant to the formation of Bi 2 WO 6 /Bi 14 W 2 O 27 heterostructure composite was discussed. The photocatalytic activities of as-prepared samples were evaluated sufficiently by using rhodamine B as target organic pollutants under visible light. The as-prepared Bi 2 WO 6 /Bi 14 W 2 O 27 heterostructure achieved enhanced optical absorption in the visible-light region, and exhibited much higher photocatalytic activities than that of pristine Bi 2 WO 6 . The optimum Bi/Co molar ratio and calcining temperature were also explored. The enhanced activities were attributed to the formation of heterostructure in suppressing the recombination of photo-generated carriers. The Co dopant species would participate to reduce the charge carrier recombination by acting as trapping sites for photogenerated charges. A possible photocatalytic mechanism over Bi 2 WO 6 /Bi 14 W 2 O 27 heterostructure was proposed.