Bi2MoxW1-xO6 solid solutions with tunable band structure and enhanced visible-light photocatalytic activities

Abstract Semiconductor photocatalysis is an effective green way to combat water pollution. For the first time, this study reports a novel method to develop Bi 2 Mo x W 1- x O 6 solid solution with microsphere structure through anion-exchange method. All Bi 2 Mo x W 1- x O 6 samples exhibit an Aurivillius-type crystal structure without any secondary phase, confirming that in complete solid solutions as the value of x increases, the band gap energy of Bi 2 Mo x W 1- x O 6 solid solutions decreases, while the optical absorption edge moves to longer wavelength. The Raman spectra research shows an increase in orthorhombic distortion with progressive replacement of W sites in Bi 2 WO 6 with Mo 6+ ions. Compared to Bi 2 MoO 6 and Bi 2 WO 6 samples, Bi 2 Mo 0.4 W 0.6 O 6 sample displayed best photocatalytic activity and cycling stability for degradation of RhB dye. The enhanced photocatalytic activity of Bi 2 Mo 0.4 W 0.6 O 6 sample can be synergetically linked to hierarchical hollow structure, enhanced light absorbance, and high carrier-separation efficiency. Additionally, the hollow Bi 2 Mo x W 1- x O 6 microspheres formation can be attributed to the Kirkendall effect.